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TDMA User Manual - MicroBee Systems

1. 0x0D82 0x0D85 OxOF 41 OxOF73 OXOFFF EEPROM write command example If e the Delimiter on the local radio where the command is issued is set to 0x77 which will appear in the TDMA Menu as 119 e we need to store 0x20 in the OxOF2E location then the command will be 0x770x000x050x000x310x010x0F0x2E0x20 Output format 0xDD 0x00 0x05 0x00 0x31 0x01 0xMSB Address 0xLSB Address data N 0x01 Write operation Cid NY OxMSB Address The MSB of the EEPROM address where the data will be o o o o o 51 TDMA User Manual Appendix ed data Data hex value to be loaded starting from Address specified above one byte OxLSB Address The LSB of the EEPROM address where the data will be No stored Output string example at the local radio If e the Delimiter on the local radio where the command is issued is set to 0x77 which will appear in the TDMA Menu as 119 e 0x20 was stored at the address OxOF2E then the command will be 0x770x000x050x000x310x010x0F0x2E0x20 52 TDMA User Manual Appendix EEPROM read command format 0xDD 0x00 0x05 0x00 0x31 0x00 0xMSB Address 0xLSB Address data Meaning format User adjustable Delimiter hex value Command length s s s OxLSB Address The LSB of the EEPROM address which we want to read the data from iHi data Dummy data hex value one byte only Yes N N N the data from wh
2. He Char Dee He Char Dee Hex ena o o nu j e o Je is so jw fo i o sa je a fa Jj uz Je j jJ rs ja 2 o sx e e fB mo Js te Jo j s o Jex j e a Je fii fs jmes o a o eor jos a p uo ss P me Po s o eo amp j e as Je fis s v jue Jes 6 o fax j vo fe Je us s fis o J 7 Jor ee n a fe fes Js J m o y s Jo fess v us Jau is pue p fo fco o9 Jo res z Je fi J us s J ot c io foa ir 74 Ja y J fis sa 22 CA u os w j s Jk p juo s 203 sc cc o c 5 j Lug o o 1j 2 j __ _ 2 mE 2 foc frre ss face fi o s foo i5 o fcr j 7 Jm Juin so yq 4 J so 5 vs w uo e j s is for fa Pj v e Jo us ese 207 Lis io poe so s Je m o J qj 2 u foa J gu s Jo us fo fo as bez _ se fs Jr p m o j fno pig 1 fes J s s Js ju os ts o 20 i oa s s Jr is o or oa a fis wac J ss fs Ju m pos fos s 22 ie sn se s v w E Bo Fs pa is tg et 3 so a 2 f us 72 fe j us 2 j o2
3. No additional characters or control commands are included with the data Control of the packet size is not necessary because the radio will automatically parse the data into packets before it is transmitted Packetized mode does require control of the packet size The data that is received from the RS 232 must contain a header packet which contains a delimiter 3 byte address byte count and the data This header packet size can vary depending on the type of action is required The CTS clear to send line can be used to synchronize data transfer to the radio over the RS 232 port It will remain asserted high until the beginning of a scheduled transmitting slot At the beginning of the slot the CTS line is de asserted low and remains de asserted for the duration of the slot It is asserted high at the end of the slot To prevent fragmentation of data packets it is recommended to trigger the data transfer to the modem on the rising edge of the CTS The CTS line will de assert when the internal 1KByte buffer gets full The CTS line will stay de asserted until the internal buffer starts to empty The CD carrier detect line is de asserted when the radio has power Once the slave syncs the CD light on the radio modem turns solid green For all radios other than the master the CD light will stay green as long as the slave radios are synchronized with the network Table 3 CD Light and Line States CDLight S Green Insyncwith networ
4. es OxMSB Address The MSB of the RAM address where the data will be stored C OxLSB Address The LSB of the RAM address where the data will be stored C it data Data hex value to be written to the specified RAM location one byte only Note The address could be one from the range below 5800 5900 TDMA Frame Table RAM write command example If e the Delimiter on the local radio where the command is issued is set to 0x77 which will appear in the TDMA Menu as 119 e we need to store 0x20 in the Ox58FE location then the command will be 0x770x000x050x000x320x010x580xFE0x20 Output format 0xDD 0x00 0x05 0x00 0x32 0x01 0xMSB Address 0xLSB Address data N 0x01 Write operation CN OxMSB Address The MSB of the RAM address where the data will be stored o o o o o 55 TDMA User Manual Appendix ee OxLSB Address The LSB of the RAM address where the data will be stored data Data hex value to be written to the specified RAM location one byte onl Output string example at the local radio If e the Delimiter on the local radio where the command is issued is set to 0x77 which will appear in the TDMA Menu as 119 e 0x20 was stored at the address Ox58FE then the command will be 0x770x000x050x000x310x010x580xFE0x20 56 TDMA User Manual Appendix RAM read command format 0xDD 0x00 0x05 0x00 0x32 0x00 0xMSB Address 0xLSB Addr
5. 13 472488ms A master slot would take master packet size 69 444us 2 917ms 100 69 444us 2 917ms 9 8614ms Step 4 The Number of SubMasters and the Number of Slave Repeaters per Frame are the next parameters to consider From the description above we know that one of the radios Radio C in our example is going to be a repeater The radio which repeats the master s signal is labeled as a SubMaster In our case Radio C will be our only submaster in the system Due to the fact that signals from radios B D and E cannot be heard directly by the master the number of repeaters in the system would only be one 1 Radio C can hear and be heard by the master and the slaves Therefore the Number of SubMasters should be set to one 1 and the Number of Slave Hepeater per Frame should be set to one 1 as well Step 5 Number of Slave Frames per Master Frame is the next parameter to set Referring back to our example we know that radios B C D and E have GPS receivers connected to them We also know that Radio C is going to be a SubMaster and a Repeater for the network Although Radio C has been designated as a SubMaster and a Repeater it will also operate as a slave Therefore the number of slaves in the system per master frame will be four 4 Step 6 The next parameter we needed to set is Number of Master Frames in Epoch As you recall an Epoch is a period of time that combines 1 or more frame casings In our case we have fo
6. 255 are valid entries Delimiter in the command must match Packet Delimiter Character settings Otherwise the command will be discarded without evaluation The command must contain at least 5 bytes The first four bytes of any command should not be included in the Command length calculations For example the length of the command OxDD 0x00 0x02 0x00 0x44 0x00 is 2 bytes The command string must not include lt LF gt CR or any other symbols unless specified in the command format Comas listed in the command format only for easier to read purpose Comas must not be included when issuing the command to the radio Replies returned back by the radio do not include lt LF gt CR or any other symbols unless specified in the return string format Comas listed in the radio replies formats are for easier to read purpose only and will not be a part of an actual radio s reply In this document Yes under the column labeled User adjustable means that the corresponding byte within the command may need some user adjustments Respectively No under the same column means that this value should stay the same as specified in the command format or can not be adjusted because it is a part of radio s response For example the Delimiter for all commands will need to be chosen by the user according to Packet Delimiter Character settings However the user can adjust no bytes within the response sent back by the
7. 472488ms 2 26 9450ms 1 Master frame time 6 8614ms 1 Number of submasters 6 3892ms 2 12 7784ms Time for all Slaves in 1 frame casing 26 945ms Number of slave frames per master frame 26 945ms 2 53 89ms An epoch time will be TDMA User Manual Examples of TDMA Networks 1 frame casing time without system sit 12 7784ms 53 89ms 66 6684ms 1 frame casing time with the system slot 66 6684ms 0 833328ms 67 5017ms Epoch time 1 frame casing time Number of master frames in epoch 67 5017 ms 2 135 0035ms Comparing to what we had in the Example 1 Epoch time from the Example 3 Epoch time from the Example 1 135 0035ms 128 336ms 1 052 The new epoch time is about 5 longer than what we had before Obviously this increment is due to the fact that there is one extra System Slot and one extra header in the beginning of the master frame But in some cases it might be beneficial Following table shows master transmission time calculations 10 seconds period of time was used for comparison Table 6 Example 3 Timing Comparison NEL oo Ee ms mI C EM ms 1 1MasterSlotttime Slot time 96814 6814 63892 3892 LT ULTIO ERR RD OR RR Total master frame time perepoch 19 7228 255568 Epoch time d 128336 1350035 L 28 wA Jd l Number of epochs within 10 sec period Total Master transmission time in 10sec period 1 538 4 1 891
8. Percentage of packets sent from the master which were successfully decoded by addressee during the frame 00 slot 0 DataByte3 Average signal level measured by the addressee during master s transmission during the frame 00 slot 0 DataByte 2 i 2 Percentage of packets sent from submaster i which were successfully decoded by the addressee during the frame 00 slot i DataByte 2 i 3 Average signal level measured by the addressee during submaster s i transmission during the frame 00 slot i Output string example at the master radio the Delimiter on the addressee is set to 0x77 which will appear in the TDMA menu as 119 the addressee has serial number 900 1234 0x890x590x1 2 the addressee is a slave there are no submasters in the system Number of SubMaster in the TDMA menu is set to 0 RadioStatistics Menu on the addressee reads 29 for average noise level Please note that actual average noise value returned by the addressee will be greater than shown in the RadioStatistics by 16 29 16 45 or Ox1D 0x10 Ox2D e the percentage of master packets successfully decoded by the addressee is 95 Ox5F TI TDMA User Manual Appendix the average signal level measured by the addressee during master s transmission frame 00 slot 0 is 87 0x57 Then the output string will be 0x770x000x070x000x370x890x590x120x2D0x5F0x57 the delimiter on the addre
9. Xmit Rcv Frames A Transparent Data Operation B FrameTable Reset on Disconnect te Disconnect Message D End of Data Character 0 255 E Overwrite Assigned Buffer F Time Delay 0 238 Esc Exit to Main Menu Enter Choice TDMA User Manual TDMA Setup Parameters Following is a brief description of the TDMA parameters 0 TDMA Data Communication Mode 0 1 Note This parameter can be mixed across the radio network 0 Transparent Mode Data is transferred to and from the RS 232 port without a header packet This mode allows relatively dumb devices to transfer data to and from the radio without the need to compile or de compile the header information 1 Packetized Mode All data to and from the radio begins with a header that contains delimiter addressing and or a command and the data Therefore the device connected to the radio in packetized mode must be capable of compiling or de compiling a header packet which is associated with the data In general there are two types of information that can be sent to the radio in a packetized mode command or data A command can be addressed to a local radio or to a remote radio The data can be broadcast or can be sent to a specific remote radio Moreover the data can be sent in the packetized mode as an assigned data or as an immediate data Please refer to the Appendix A for more details on the command data sending in the packetized mode 1 Slave Data P
10. Yes length data Data packet in hex format Yes Command example If e the local radio serial number is 900 1234 0x890x590x12 e one of the remote radio s serial number is 900 5678 Ox890x6A0x6E then the command will be Send 123456789A data packet to the remote radio with serial number 900 5678 as immediate data 0x770x890x6A0x6E0x0A0x010x020x030x040x050x060x070x080x090x0A 91 TDMA User Manual Appendix The string on output of the 900 5678 radio s RS232 port if it was listening during the frame picked up by local radio for the transmission will be 0x770x890x6A0x6E0x0A0x010x020x030x040x050x060x070x080x090x0A Broadcast 123456789A data packet to all remote radios and send it as assigned data 0x770x890x590x120x0A0x010x020x030x040x050x060x070x080x090x0A The string on output of one of the remote radio which heard this message during the frame assigned to the local radio will be 0x770x890x590x120x0A0x010x020x030x040x050x060x070x080x090x0A Broadcast 123456789A data packet to all remote radios and send it as immediate data 0x770xFFOxFFOxFFOx0A0x010x020x030x040x050x060x070x080x090x0A The string on the output of the RS232 port of all of the radios which heard this message will be 0x770xFFOxFFOxFF0x0A0x010x020x030x040x050x060x070x080x090x0A 92 TDMA User Manual Appendix Appendix B ASCII Table dec hex char Table 11 ASCII Hex Dec Table De Hex Char Dee
11. be 0x770x000x030x000x630x360x38 7A TDMA User Manual Appendix Note The output may only have one return value and there is a lookup table available from FreeWave Here is the current table as of the writing of this manual In this case the output will be given firmware of 5 85 0x770x000x020x000x630x69 Firmware Ver TDMA Command value TDMA Command value RENE NEN a RN 563 O a e i emm om 56 685 Jq 45 J 587g 0 0 0 0 0 71 0 47 se 78 s o AB 875 99 8 Ll 5e p M f SE y Ol Be SENT o O O IE SE J 580 0 98 L 88 3 S 58 10 A4 66 584 10 68 Firmware Ver TDMA Command value TDMA Command value Decimal Hexadecimal 75 TDMA User Manual Appendix 10 7 Tell remote radio to respond with its signal quality packet on specified frame Command general description Addressee is a local radio or a remote radio Remote Command restrictions Can be issued only from the master Terminology used Remote radio of interest will be called addressee Command format 0xDD 0x00 0x05 0x00 0x37 0x Ox 0x 0xNN Meaning format User adjustable Delimiter byte hex value Yes O Command length No O OxiHt Oxdiit OXHH Addressee s 3 byte address Yes Frame number in hex format Ye N N Ye e S o o S S Command exa
12. in the TDMA Menu as 119 e 0x20 was stored at the address 0x5801 frame 01 then the command will be 0x770x000x050x000x610x010x580x010x20 68 TDMA User Manual Appendix 69 TDMA User Manual Appendix Read command format OxDD 0x00 0x6 0x00 0x61 0x00 0xStart MSB address OxStart LSB address 0OxEnd MSB address 0xEnd LSB address es e Address Address Read command example i OxStart MSB Start reading at this address MSB of this address Ye Address E Ye e o o o S S S S i OxStart LSB Start reading at this address LSB of this address Address i 0 If e the Delimiter on the local radio is set to 0x77 which will appear in the TDMA Menu as 119 e we need to read frames 01 at the address 0x5801 through 03 at the address 0x5803 then the command will be 0x770x000x060x000x610x000x580x010x580x03 Note maximum allowable EEPROM read length is 140 EEPROM locations Output format OxDD 0x00 0x4 data size 0x00 0x61 0x00 0xMSB Address 0xLSB Address data Output string read command example If e the Delimiter on the local radio is set to 0x77 which will appear in the TDMA Menu as 119 e we read from 0x5801 frame 01 to 0x5803 frame 03 e the data read was 0x00 0x20 and 0x21 then the command will be 0x770x000x070x000x610x000x580x010x000x200x021 Reading or Writing to invalid EEPROM locat
13. of radio s temperature measurements Note use given below formulas to convert this Hex value into deg C OxRD Byte of data that corresponds to the status of RTS and DTR N inputs on the radio Bit 7 MSB is the RTS line and Bit 4 is 79 TDMA User Manual Appendix the DTR line 1 corresponds to a low level on these pins Output string example at the local radio If the Delimiter on the local radio is set to 0x77 which will appear in the TDMA Menu as 119 the remote radio s serial number is 900 1234 0x890x590x1 2 the input DC voltage measured by the radio is 12VDC OxCC the radio s temperature 25 deg C 0x80 RTS is low and DTR is high 0x10 then the output string will be 0x770x000x070x000x420x890x590x120xCC0x800x10 Use listed below algorithm to convert OxTp value into deg Centigrade e Convert OxTp readings from the radio into an integer number Temp e Make sure that the value of OxTp after conversion is between 6 and 255 e Calculate the result as follows Temp Temp 256 Temp Temp 22 1 Temp 256 25 Temp 0 0196 SQR 0 0196 2 4 LOG10 Temp 0 000057 Temp Temp 2 0 000057 Temp 25 Temp Note Does not work for local radio 80 TDMA User Manual Appendix 12 F Special Data Packet command Sends data to a specific radio or radios on a specified frame Command general description Ignores delim
14. radio J 49 TDMA User Manual Appendix TDMA Packetized Commands 1 0 Tell local radio to return its radio ID Command general description Addressee is a local radio or a remote radio Local Command format OxDD 0x00 0x01 0x00 0x30 Meaning format User adjustable Delimiter byte hex value Command length Command example 0x770x000x010x000x30 Output format at the local radio 0xDD 0x00 0x04 0x00 0x30 0x 0x 0x Field name Meaning format User adjustable OxDD Delimiter byte hex value 0x04 Command length 0x30 Ox t OXHH OXHH Local radio s 3 byte ID number Output string example at the local radio 0x770x000x040x000x300x890x590x12 50 TDMA User Manual Appendix 2 17 EEPROM individual address write and read command EEPROM write command format Command general description Addressee is a local radio or a remote radio Local Radio will reset after reception of the program command and will re acquire the network assuming no network sensitive parameters were changed EEPROM write command format 0xDD 0x00 0x05 0x00 0x31 0x01 0xMSB Address 0xLSB Address data 0x05 Commandiength CN O31 Commandcode CN 0x01 Write operation TN No No No stored The LSB of the EEPROM address where the data will be stored it data Data hex value to be loaded starting from Address specified above one byte Note The address could be one from the list below 0x0D81
15. radio the radio creates an exact copy of the original frame table in the RAM This copy is named a temporary frame table and will be used by the radio from that moment until the next power on off cycle The temporary frame table can not be edited from the TDMA menu but the whole table or any part of it can be changed and edited by using special commands if the radio is in the packetized mode Moreover this frame table can be reset back to the original frame table or can be kept after radio looses synch to a master depending on the FrameTable Reset on Disconnect settings CRC Cyclical Redundancy Check The FreeWave Radios implement a 32 bit CRC check on all data packets to guarantee correct data TDMA User Manual TDMA Setup Parameters TDMA Setup Parameters The TDMA mode is activated by entering the radio s setup mode and selecting option zero from the menu Once in the Operation Mode menu enter 8 for TDMA Escape back to the Main menu and enter 6 for TDMA parameter menu Refer to Table 1 for an example TDMA parameter table Table 1 TDMA Parameters List TDMA Parameters FreeW ave HyperT erminal 0 TDMA DataCommunications Mode t1 Slave Data Packet Size 8 240 2 MasterData Packet Size 8 240 3 Number of SubMasters 0 15 4 Slave Frames per Master Frame 1 15 5 Slave Repeaters per Frame 0 15 6 Master Frames in Epoch 1 85 7 Packet Delimiter Character 0 255 8 System Slot Length 0 255 9 Edit
16. radio to be idle on specified frame 82 16 R Tell remote radio to become a repeater submaster 83 17 T Tell remote radio to transmit on specified frame 85 18 m Gather routing information from source radio to destination radio 86 19 Send data packet to a specified radio or broadcast 88 Appendix B ASCII Table dec hex char 90 Appendix C Firmware Tables 92 TDMA User Manual FreeWave TDMA general description FreeWave TDMA general description The FreeWave Time Division Multiple Access TDMA protocol is an enhanced and sophisticated version of point to multipoint communications The TDMA protocol provides timing and other parameters which in turn allow large networks of radios to work in a non polled environment This would be useful for example in a network of GPS stations If the GPS receivers report in an un polled manner numerous packet collisions would occur if a standard multipoint network was used The TDMA protocol provides the timing parameters to allow each radio to report in at a predetermined time The basic concept of the TDMA protocol is that each radio within a network is assigned a specific time slot to transmit a message receive a message repeat another radio s message or do nothing 1 to 16 slots can be assigned to either a s ave frame or a master frame A single master frame and 1 to 15 slave frames can be assigned to a frame casing A number of frame casings are assigned to an epoch An epoch is
17. show the previous value and its packet decode success will drop to zero e Does not work for local radio TDMA User Manual Appendix 11 B Tell remote radio to transmit a status packet on specified frame Command general description Addressee is a local radio or a remote radio Echoed out at all radios that are programmed to listen in the frame table except queried radio Command format 0xDD 0x00 0x05 0x00 0x42 0x Ox 0x 0xNN User adjustable Delimiter byte hex value Command length Ox Ox Ox Destination radio s 3 byte address Frame number in hex format Command example If e the Delimiter on the local radio is set to 0x77 which will appear in the TDMA Menu as 119 e the remote radio s serial number is 900 1234 0x890x590x12 e the frame number will need to used for the 900 1234 radio s response is 05 then the command will be 0x770x000x050x000x420x890x590x1 20x05 After this command will be received by the radio 900 1234 it will send its status packet on the frame 05 Output format at the local radio 0xDD 0x00 0x07 0x00 0x42 0x Ox 0x 0xVt 0xTp 0xRD Meaning format User adjustable Delimiter byte hex value Command length Ox t OXHH OXHH Destination radio s 3 byte address No o OxVt Byte of data that corresponds to the sample of radio s input DC voltage measurements with 15VDC being a full scale OxTp Byte of data that corresponds to the sample
18. transparent to the user All packets transferred to or from the radio to the RS 232 port are strictly data with no header attached Each RF packet transmitted contains a 5 byte header packet which includes the delimiter character the three byte serial number of the radio and the number of characters within the data message A radio in transparent mode that receives a transparent or packetized packet strips off the header packet before it is transferred out to the RS 232 port of the radio A radio in packetized mode that receives a message from a transparent mode radio transfers the header packet along with the data message out the RS 232 port of the radio TDMA User Manual Definitions Local radio Local radio is a radio which is connected through the RS232 port to equipment that generated a command or data to be evaluated by the radio Remote radio Remote radio is a radio which is a part of the same TDMA network with the local radio and which potentially can hear transmissions from the local radio directly or through a repeater s submaster s Original and temporary frame tables Each radio in the TDMA operation mode stores its frame table in two different memory blocks The original frame table is stored in the EEPROM and can be viewed and edited from the TDMA menu This table is a hard copy of the frame table which assures that the radio will return to a known state after each power on off cycle When the DC power is applied to the
19. will include zeros in the position of the radio whose signal quality packet was requested e The average signal level from x radio is only updated when x radio is heard Therefore if x radio is turned off the average signal level will still show the previous average and its packet decode success will drop to zero TDMA User Manual Appendix 9 c Get radio s firmware version number Command general description Addressee is a local radio or a remote radio Local Command format OxDD 0x00 0x01 0x00 0x63 Meaning format User adjustable Delimiter hex value S Command length Command example If e the Delimiter on the local radio is set to 0x77 which will appear in the TDMA Menu as 119 then the command will be 0x770x000x010x000x63 Output format at the local radio 0xDD 0x00 0x03 0x00 0x63 0x 0x Meaning format User adjustable Delimiter hex value No Command length No No Ox Ox F w version extension For example if the radio has 5 58 No version of f w it will return 0x350x38 Output string example at the local radio e the Delimiter on the local radio where the command is issued is set to 0x77 which will appear in the TDMA Menu as 119 e the local radio has 5 58 version of the fw e the output characters are the ASCII codes of the decimal places of the firmware version 0x36 is the ASCII code for 6 and 0x38 is the ASCII code for 8 then the output string will
20. your settings All of the setting in these menus define the radio functionality in the TDMA network in the same manner as they do so in other network types Peer to Peer Point to Point or Point to Multipoint Please refer to the User Manual for more details Point to Multipoint Menu 1 Master Packet Repeat TDMA User Manual TDMA Related Parameters Setting this parameter to a number greater than zero 0 will allow each message data packet or command sent from the master slave or slave repeater radio in the TDMA network being repeated by sending radio an appropriate number of times The message is repeated in the following assigned frames 6 Network ID This parameter adds exactly the same functionality to the TDMA network as it does to the Point to Multipoint network In general only radios with the same Network ID settings will be able to communicate with each other in the TDMA mode Note The NetworklD contains 2 bytes but in the TDMA system only the least significant byte LSB is used by the radio Therefore if the NetworklD is set to 269 0x010D for example the radio can potentially communicate with another TDMA network which has NetworklD set to 13 0x000D 8 MultiMasterSynch In the TDMA mode this parameter allows synchronization between a few co located TDMA masters When MultiMasterSync is set to one 1 the co located TDMA masters will be synchronized to each other in a manner similar to Point to Poin
21. 00 00 oo oo 00 oo 00 oo oo 00 00 oo oo oo oo 00 c Slave refer to Radio B 0 1 2 3 4 5 6 7 8 9 A B C D E F 00 32 oo oo 20 21 oo oo oo 00 oo oo oo 00 oo oo 00 10 o0 oo oo oo oo oo co oo oo oo oo foo oo oo 00 foo 20 o0 00 oo oo 00 oo 00 oo oo 00 00 oo oo oo oo 00 d Submaster Repeater and Slave refer to Radio D 0 1 2 3 4 5 6 7 8 9 A B C D E F 00 10 00 00 oo 20 oo oo oo oo oo oo oo 00 00 oo 00 10 o0 oo foo oo oo oo co oo oo oo oo foo OO oo 00 OO 20 o0 00 oo oo 00 oo 00 oo oo 00 00 oo oo oo oo 00 e Slave refer to Radio E Radio A On the Master radio the master frame frame 00 is set to 20 the other four frames are set to 10 This assures that the Radio A will listen to all of the remote radios transmissions Improvement note Due to the fact that the master radio can hear only Radio C it is possible to setup the master s frame table with 20 in the frame 00 10 in the frame 01 and 00 in the rest of the frames As a matter of fact this frame table configuration will allow a slight reduction in master radio power consumption 41 TDMA User Manual Examples of TDMA Networks because during the frames 02 through 04 master will be idle instead of being in the receive mode Radio B There are no changes being made to the frame table of this radio C
22. 0x0890x590x120x050x000x020x05 TDMA User Manual Appendix 19 Send data packet to a specified radio or broadcast Command general description Addressee is a local radio or a remote radio Remote Ignores delimiter characters in the data packet This command is suitable for random binary data Command format Send data packet to a specified radio as immediate data 0xDD 0x 0x 0x 0xdata packet length data where Ox 0x 0x is different from local radio serial number and it is not OXFFOxFFOXxFF broadcast data packet and send it as assigned data 0xDD 0x 0x 0x 0xdata packet length data where Ox 0x 0x is local s radio serial number or broadcast a data packet and send it as immediate data OxDD OxFFOxFFOXxFF 0xdata packet length data User adjustable Yes Ox Ox Ox Destination radio s 3 byte address There are three options Yes available e This address is something different from local radio serial number and it is not OxFFOxFFOXxFF In this case the command will be sent as immediate data and will be addressed to a specified remote radio only This address is local s radio serial number In this case the command will be sent as assigned data and will be addressed to all remote radios broadcast This address is OxFFOxFFOXxFF In this case the command will be sent as immediate data and will be addressed to all remote radios broadcast Oxdata packet Number of data bytes to be sent
23. 1 frame casing time without system sio Calculations in Example 1 we know that the duration of epoch Time for 1 epoch 1 frame casing time without system so System slot time If the System Slot Length is set to eight 8 then the system slot time will be 1 System slot time System Slot Length 4 69 444us 833 328us Therefore the epoch time 1 frame casing per epoch will be Time for 1 epoch 127 5027ms 833 328ys 128 336ms So the master in Example 1 can send up to 100 bytes refer to Master Data Packet Size settings every 128 336ms The number of slaves we currently have is four 4 For explanation purposes we can divide these slaves into two groups two slaves per group Each group will need to have its own master frame with the system slot before it Therefore the following changes should be made in the TDMA Parameters menu e Master Data Packet Size set to 50 instead of 100 e Master Frames in Epoch set to 2 instead of 1 e Slave Frames per Master Frame set to 2 instead of 1 Please note that the frame table on all of the radios does not need to be changed To find what effect on the radio performances these changes will have let s make timing calculations similar to the ones given in the Example 1 1 Slave slot time 152 69 444us 2 917ms 13 472488ms 1 Master slot time 50 69 444us 2 917ms 6 3892ms 1 Slave frame time 13 472488ms 1 Number of repeaters 13
24. 2 P Timing comparison of the original system configuration Example 1 and after an additional master frame has been added to the epoch with no other settings changed Example 3 So adding one extra master frame per epoch to our original setup increases master transmission time by about 23 if the rest of system parameters have not being changed This means that the remote radios will have 23 higher chance to synchronize to the master than before for the price of about 5 system s throughput degradation and some minimal power consumption increase on the master radio Note The data in the Table 5 was calculated based on assumption that the master in both examples transmits continuos data If the master will transmit no data but the header packets only the difference between Example 1 and Example 3 configurations will be even higher In conclusion adding an extra master frame per epoch might be beneficial in applications where primary synchronization between the radios is an issue But to 45 TDMA User Manual Examples of TDMA Networks achieve the highest slave to master data throughput the number of master frames per epoch should be as low as possible TDMA User Manual Examples of TDMA Networks Example 4 Note The purpose of this example is to show how to set up the radios when they are setup to have more than one Master Frame per Epoch For this example the radios were set up with the following parameters Slave Frame
25. 799ms 127 5027 ms From our experience in some applications it 5 beneficial to have a TDMA radio network synchronized to the GPS data dumping timing Let s consider a case when slave radios generate GPS data every 150 msec Going back to our 1 frame casing time without system slot calculations it is obvious that in order to synchronize the radio system to the GPS timing the TDMA system epoch duration has to be increased by about 22 5 msec or so As mentioned before the system slot may help us to do this The following shows the calculations for determining the system slot length 150ms 1 frame casing time without system sit System slot time 150ms 127 5027ms System slot time System slot time 150ms 127 5027ms 22 4973ms Replacing System slot time with System Slot length 4 69 444us we get System Slot length 4 69 444us 22 4973ms System Slot length 22 4973ms 0 277776ms 69 444us System Slot length 31 9982 Therefore the System Slot Length needs to be 32 for an epoch timing being 150 msec 36 TDMA User Manual Examples of TDMA Networks Step 8 The next parameters Packet Delimiter Character Transparent Operation Frame Table Reset on Disconnect Disconnect Message End of Data Character and Overwrite Assign all need to be set The Packet Delimiter Character can range from 0 to 255 It does not make any difference on the functionality of the radi
26. Manual Examples of TDMA Networks Figure 10 shows a listing of the master table slave table and the slave repeater submaster tables 0 1 2 3 4 5 6 7 8 9 A B C D E F 20 10 10 10 10 oo oo oo ooj ooj OO oo oo oof OO OO 00 oof oo oo oof oof ooj oo oof oo oof oo oof OO OO OO 00 ooj oo oo oo oof ooj oo ooj oo oof oo oof oof oo 00 a Master stations radio frame table setup Master slot 00 0 c Slave refer to Radio B e Slave Refer to Radio E Figure 11 Example 1 Frame Table In a the master frame table 00 0 is set to 20 the other 4 frames are set to 10 This assures the radio will hear what is broadcasted in these frames and will be sent to the serial port In b shows the frame table of Radio C In the frame O slot 1 00 1 the radio retransmits what it heard in slot O and outputs it to the serial port In frame 00 1 the 38 TDMA User Manual Examples of TDMA Networks radio is a slave and should send its data in this frame The frames 00 2 00 4 acts as repeater frames and the data which it hears is repeated on slot 1 Since the upper nibble is a 2 the data is not sent out to the serial port In c the slave is told to listen and output what it hears on 00 0 do nothing for frame 00 1 00 3 and 00 4 In frame 00 2 the radio is to transmit the data In d the slave is told to listen and send what it hears to the serial port in frame 00 0 For frames 00 1 00 2 and 00 4 the radio is tol
27. TDMA User Manual Revision 3 0U Feb 13 2004 FreeWave Technologies Inc 1880 South Flatiron Court Boulder CO 80301 USA Ph 303 444 3862 TDMA User Manual Needs discussion of frame table size set to 109 to satisfy fcc requirements at 112 with an even frame table you end up with an aliasing effect where the radio actually only hops on 56 frequencies With either an odd hop table or an odd frame table things shift in time and fcc requirements are met TDMA User Manual About this document About this document General information This document covers the TDMA protocol available with the FreeWave spread spectrum transceivers Revision History Table 1 shows revision history of this document T able 1 Revision H istory 30m 300 NoviS 200 fo 300 Sep1L200 00000000 000000 3o ooo ooo O Dec3 2002 Aug 4 2003 Addition of special packet command parameters 3 0s Oct 28 2003 Fixed total frames in epoch discussion Added mention of RF data rate in setup parameters Dec 9 2003 Added firmware version table 3 0U Feb 13 2004 Added note of no local operation to signal quality and status packets Added description of retry timeout Dec 3 2002 Misc in examples frame table commands How to contact us We can be reached at FreeWave Technologies Inc 1880 S Flatiron Court Suite F Boulder CO 80301 Ph 303 444 3862 Fax 303 786 9948 WWW freewave com TDMA User Manual About
28. a slave repeater during a slave frame Submaster A submaster is a radio that repeats a master in a master frame A submaster does not need to hear the master directly as long as it hears one submaster before it in the same master frame A submaster will obtain its synchronization only from the master or a preceding submaster A network can have a maximum of 15 submasters Slave A slave is a radio which originates messages and synchronizes itself with a submaster or the master A slave radio can act as a repeater for other slaves in any frame which is not the originating radio Slave repeater A slave repeater is a radio that repeats a slave transmission within a slave s frame Repeaters are assigned a specific slot within the slave frame to repeat any messages heard in a preceding slot A radio cannot transmit an originating message and then repeat it in the same frame The repeater does not need to hear the original message from the slave as long as it hears one repeater before the assigned transmission slot Note that a slave can be and often is a repeater in any frame that is not the originating radio A repeater will obtain its synchronization and must periodically hear from a master or one of the submasters TDMA User Manual Definitions Assigned data and immediate data When the data packet is received from the RS232 port radio will process it during the system slot time and may transmit it as assigned data or as immediate data
29. acket Size in bytes 8 240 This allows the user to assign the maximum number of data bytes in a packet which can be sent within one slot The minimum packet size is 8 and the maximum size is 240 While TDMA timing is all based on a RF Data Rate of 3 the TDMA protocol can be run at a RF Data Rate of 2 When at 2 the packet sizes change from a maximum of 240 bytes down to a maximum of 180 bytes Note Firmware versions up through 900 MHz 5 85 2 4 GHz 1 85 and 225 MHz 1 07 only support Slave Data Packet sizes up to 239 bytes Note The radio will break data up into packets by two methods the first is a break in the data stream and the second is at the set data packet size 2 Master Data Packet Size in bytes 8 240 This allows the user to assign the maximum number of data bytes in a packet which can be sent within one master slot TDMA User Manual TDMA Setup Parameters While TDMA timing is all based on a RF Data Rate of 3 the TDMA protocol can be run at a RF Data Rate of 2 When at 2 the packet sizes change from a maximum of 240 bytes down to a maximum of 180 bytes Note The radio will break data up into packets by two methods the first is a break in the data stream and the second is at the set data packet size 3 Number of Submasters 0 15 This parameter assigns the number of submasters master repeaters within each master frame The maximum number of submasters allowed in the network is fifteen An entry of
30. adio within 200 msec after its corresponding 1 PPS These only have to be sent during the radio acquisition phase but more than one may be needed until the radio has synched up Time Stamp format 0xDD 0x00 0x04 0x00 0x45 0xMSB of TimeStamp OxLSB of TimeStamp SecondsPerEpoch OxMSB of TimeStamp TimeStamp is a 16 bit number which is the number of and seconds within an arbitrarily defined GPS epoch If the OxLSB of TimeStamp GPS epoch is defined as one hour then the range of TimeStamp will be 0 3 600 A better epoch may be 7 hours giving a range from 0 25 200 SecondsPerEpoch SecondsPerEpoch is defined as the number of seconds for a TDMA Epoch The minimum allowed is 1 Any other value must divide into the defined GPS Epoch If this Epoch length is 3600 seconds 1 HR then the allowed values of SecondsPerEpoch is 1 2 3 4 5 6 8 9 10 12 15 etc An epoch length of 7 hrs will allow a value of 7 for SecondsPerEpoch to be used 3 The TDMA parameters MUST be set up so that a TDMA Epoch lasts exactly the number of seconds in SecondsPerEpoch The SystemSlot parameter is useful to fine tune the Epoch length 4 A slave radio will try to synchronize through the RF while waiting for the TimeStamp packet 5 When synched up all radios must continue to get the 1 PPS If a PPS is missed the radio will return to acquisition mode 21 TDMA User Manual TDMA Related Parameters 22 TDMA User Manual Programming the Frame Table Progra
31. allowed in a network The master frame is the heartbeat of the network It transmits synchronization and timing data to every radio within the network either directly or indirectly through submasters Figure 7 Master Frame Frame 00 0 the first frame in the frame table Figure 7 is special and represents the action of the radio during all master frames No other frame can be set as a master frame All master frames must be identical unlike slave frames that can change after each master frame within an epoch All successive master frames as specified by the parameter Master Frames per Epoch DO NOT show up in the frame table they have the same settings as the 00 0 frame In other words the master frame shows up only once in the frame table at 00 0 but in time there is one master frame per frame casing Master s Frame Table 0 1 2 3 4 5 6 oo 20 10 10 20 10 10 00 OO Slave 1 Frame Table 0 1 2 3 4 5 6 SURGE MEE ave rrames per aster Frame oo 21 20 10 21 20 10 oo 00 a Masia Praes rer E podi Slave 2 Frame Table 0 1 2 3 4 5 6 oo 10 10 20 10 10 20 00 00 Implicit master frame that is exactly the same as frame 00 0 Figure 8 Implicit Master Frames TDMA User Manual Operation Modes Operation Modes There are two modes of operation in TDMA Transparent Mode and Packetized Mode When the radio operates in transparent mode all characters transferred to and from the RS 232 port are treated as data only
32. and general description Addressee is a local radio or a remote radio Local Command format 0xDD 0x00 0x05 0xx0 0x6D 0x 0x 0x 0xFF Ox Ox Ox Destination radio s 3 byte address Frame number to send the command on Command example If e the Delimiter on the local radio is set to 0x77 which will appear in the TDMA Menu as 119 e the remote radio s serial number is 900 1234 0x890x590x12 e the command has to be sent on the frame 05 0x05 then the command will be 0x770x000x050x000x6D0x890x590x120x05 Output format at the local radio 0xDD 0x00 0x05 number of slots 0x00 0x6D 0x 0x 0x 0xFF 0xSS Meaning format User adjustable Delimiter hex value slots numbers sent on N N 0xD Commandcode CN Frame number to send the command on o o o OxiHt Oxit t Ox Destination radio s 3 byte address o 0xSS slot numbers sent on example 0x00 0x01 0x03 would refer No to slot 0 slot 1 and slot3 is the route the command took Output string example at the local radio If e the Delimiter on the local radio where the command is issued is set to 0x77 which will appear in the TDMA Menu as 119 89 TDMA User Manual Appendix e the remote radio s serial number is 900 1234 0x890x590x12 e the frame used to send the command on was 05 e the command travel through slot 0 gt slot 2 gt slot 5 then the output string will be 0x770x000x080x000x6D
33. based on local radio settings Transmitting data packet as assigned data assures that the packet will be send out during radio s assigned frame as setup in the frame table The assigned data transmission mode is the most common data type for TDMA An originating message will always be transmitted on the slot number 0 of the assigned slave or master frame Immediate data means that the local radio will pick up a random slave frame within the nearest new frame casing for its transmission In this mode the packet is transmitted only one time regardless of the MasterPacketRepeat settings and can be transmitted during a slot that is assigned to a different radio since it transmits on a random slave frame Packetized mode Packetized mode allows commands to be sent and received by the radios within a TDMA network This gives the user added flexibility and the power of TDMA to solve a variety of application problems If the radio is set to packetized mode all messages transferred from the RS 232 port to the radio must be formatted into a data packet with a header All packets transferred from the radio to the RS 232 port also have a header attached so the user can utilize the information contained in the header Radios can be configured for transparent mode and packetized mode within the same network Packetized mode also allows dynamic allocation of frame configuration for each individual radio in the network Transparent mode Transparent mode is
34. cess of setting up a TDMA network Hopefully by the end of this section all questions will by eliminated and you will be ready to setup your own TDMA network Step One We have determined that five radios are needed for collecting real time data Figure 8 gives an example of the geographical location of our five radios Radio C Radio B The lines in between radios indicate that these radios can hear each other So in this figure Radio A can hear Radio C Radio C hears Radio B Radio D and Radio E Radio D hears Radio C and Radio E and Radio E hears Radio D and Radio C Figure 10 Example Network 1 Referring to Figure 8 Radio A is going to be our Master station Radio C is going be setup as a repeater station and have a GPS receiver connected to it Radios B D and E are going to have GPS receivers connected to them and will be setup as Slave stations only Step 2 The next step involves the TDMA Parameter table Figure 9 shows a default table The first parameter we need to determine is the TDMA Data Communication Mode This parameter can be select as a packetized or transparent mode The slave radios are 33 TDMA User Manual Examples of TDMA Networks connected to GPS receivers these devices cannot build packetized data Therefore these radios will be set up in transparent mode The master station can be setup in transparent or packetized mode But we want the ability to use some of the packetized commands so
35. d to do nothing Frame 00 3 the radio is told to transmit its data In e the radio is told to listen and send what it hears on frame 00 0 to it serial port not to do anything for frames 00 1 00 2 and 00 3 and to transmit its data on frame 00 4 Step 10 The radios have now been setup and are ready to go Make sure that the other parameters are setup correctly Now the system is ready to go make sure the radios have the same Network ID f you are not using the Network ID then it is imperative that the Call Books are properly programmed 39 TDMA User Manual Examples of TDMA Networks Example 2 Note The purpose of this example is to show how the frame table from the Example 1 will need to be changed if the network topology described above will be slightly different Therefore in this example we will not review all of the steps taken in the Example 1 and will concentrate on the changes in the frame table settings only Consider the same network topology as in the Example 1 but the Radio E can not hear the Radio C Figure 11 below reflects this change Radio C Radio B The lines in between each pair of radios indicate that these radios can hear each other So in this figure Radio A can hear Radio C Radio C hears Radio B and Radio D Radio D hears Radio C and Radio E and Radio E hears Radio D Figure 12 Example 2 Referring to Figure 11 Radio D will need to be programmed now to function as a submaster during the maste
36. e 1 causes a message to be transferred out through the RS 232 port The format of the message is defined by the Disconnect and Connect status message command refer to the Appendix A for more details TDMA User Manual TDMA Setup Parameters The radio must be in packetized mode for this option to have any effect D End of Data Character 0 255 This parameter assigns an ASCII character as the end of the data packet The radio looks for this character in the data it receives If the radio sees this end of data character the data is parsed into two different packets and sent at different times Note This ASCII character is in hexadecimal E Overwrite Assigned Buffer 0 1 This only applies to assigned buffer This parameter determines if the assigned buffer will be overwritten by data being received The setting of a zero 0 does not allow the assign buffer to be overwritten A setting of one 1 allows the assign buffer to be overwritten This parameter allows incoming data on the RS232 port to overwrite data already in the buffer For GPS data and such where only the current data is of importance F Time Delay 0 238 This parameter allows for a time delay to be inserted into the network The time delay is necessary for links of greater than 20 miles and absolutely critical for links exceeding 80 miles The value of the parameter should be incremented by 1 for every 10 miles over a 20 mile link For example a 50 m
37. e command format Command general description Addressee is a local radio or a remote radio Local Frame table reset on disconnect is of special interest with this command If the frame table reset option is set then any time the radio loses the link the frame table will default back to that stored in EEprom If the frame table reset option is not set then the radio will keep the frame table in RAM until loss of power upon which the radio will default back to the frame table stored in EEprom OxDD 0x00 0x4 data size 0x00 0x61 0x01 0xMSB Address 0xLSB Address data Field name OxDD 0x04 data size 0x61 OxMSB Address Start writing at this address MSB of this address OxLSB Address Start writing at this address LSB of this address data Data hex value to be loaded starting from Address specified above 0x01 Note The address could be one from the list below 5800 5900 Temporary TDMA frame table Write command example If e the Delimiter on the local radio is set to 0x77 which will appear in the TDMA Menu as 119 e we need to store 0x20 in the frame 01 on the radio then the command will be 0x770x000x050x000x610x010x580x010x20 Output format at the local radio 0xDD 0x00 0x4 data size 0x00 0x61 0x01 0xMSB Address 0xLSB Address data Output string example at the local radio If e the Delimiter on the local radio is set to 0x77 which will appear
38. e command is issued is set to 0x77 which will appear in the TDMA Menu as 119 0x770x000x050x000x4C0x890x590x120x02 After this command will be received by the radio 900 1234 its RAM copy of the frame table will have a new entry in the frame number 02 which is 10 Note after the power will be recycled on the radio 900 1234 the contents of the frame number 02 will be re stored back to the value viewable from the TDMA Menu option Edit Xmit Rcv Frames TDMA User Manual Appendix 15 N Tell remote radio to be idle on specified frame Command general description Addressee is a local radio or a remote radio Remote Command format 0xDD 0x00 0x05 0x00 0x4E 0x 0x 0x 0xNN Ox Ox Ox Destination radio s 3 byte address Frame number in hex format Command example If e The Delimiter on the local radio is set to 0x77 which will appear in the TDMA Menu as 119 e f remote radio s serial number is 900 1234 0x890x590x12 then the command will be 0x770x000x050x000x4E0x890x590x120x02 After this command will be received by the radio 900 1234 its RAM copy of the frame table will have a new entry in the frame number 02 which is 00 Note after the power will be recycled on the radio 900 1234 the contents of the frame number 02 will be re stored back to the value viewable from the TDMA Menu option Edit Xmit Rcv Frames 85 TDMA User Manual A
39. e next slave frames 30 TDMA User Manual Network Acquisition Network Acquisition A radio operating in TDMA mode will acquire the network the same way as in a standard point to multipoint mode If the radio is not the master the radio will search for any master or submaster which is in its call book If the call book is not used the Network Id must be used The radios in the network must have the same setup as far as the Radio Transmission Parameters and Multipoint Parameters There are some parameters which are not used by the TDMA mode In the Radio Transmission Parameters Max Packet size and Min Packet size are not used In the Multipoint Parameters Number of Repeaters Max Slave Retry Retry Odds DTR connect MultiMasterSync and 1PPS are not used Even though the items listed are not used it is good practice to ensure that all radios in the network have the same setting Epoch Timing The TDMA protocol allocates specific and fixed time slots to radios within the network The FreeWave Time Division Multiple Access TDMA protocol is basically for real time data collection Table 4 gives the items and a description of each that are used to calculate the transmission time of one epoch 31 TDMA User Manual Network Acquisition Transmission Timing Figure 9 Epoch Time Calculations 32 TDMA User Manual Examples of TDMA Networks Examples of TDMA Networks Example 1 This section will walk through the pro
40. e to Frequency Calculations for more details OxStart MSB Start reading at this address MSB of this address Ye Address Ye e o o o S S S S i i OxStart LSB Start reading at this address LSB of this address Address i i C Read command example If e the Delimiter on the local radio is set to 0x77 which will appear in the TDMA Menu as 119 e we need to read from 0x0E30 to 0xE32 then the command will be 0x770x000x060x000x600x000x0E0x300x0E0x32 Output format 0xDD 0x00 0x4 data size 0x00 0x60 0x00 0xStart MSB Address 0xStart LSB Address data Meaning format User adjustable Delimiter hex value No 0x04 data size Number of data bytes plus 4 No N N N N N o o o o o o Start reading at this address MSB of this address EIE Address Start reading at this address LSB of this address Address TDMA User Manual Appendix Output string read command example If e the Delimiter on the local radio is set to 0x77 which will appear in the TDMA Menu as 119 e we read from OxOE30 to OxE32 e the data read was 0x01 0xOD and OxFE then the command will be 0x770x000x070x000x600x000x0E0x300x0E0x320x010x0D0xFE Reading or Writing to invalid EEPROM locations will have the Output string OxDD 0x00 0x02 0x00 0x60 0x01 67 TDMA User Manual Appendix 7 a Bulk load of frame table into RAM Writ
41. eans to anybody Randomizing factor FF is 100 response Command example S o o o S If e the Delimiter on the local radio where the command is issued is set to 0x77 which will appear in the TDMA Menu as 119 0x770x000x050x000x480xFFOxFFOxFFOxFO Output format at the local radio 0xDD 0x00 0x04 0x00 0x48 0x Ox 0x Field name Meaning format User adjustable OxDD Delimiter byte hex value 0x04 Command length N o o 0x48 o Ox t OXHH OXHH Responding radio 3 bytes ID number Output string example at the local radio 0x770x000x040x000x480x890x590x12 Note When this command is transmitted all radios that are listening will randomly transmit an acknowledgement over the next epoch Every response will appear on RS232 output of the local radio in the order it was received In the case of no collisions the number of responses can be equal to the number of listening radios in the network Repeating this command over should eventually result in a response from all radios in the network 83 TDMA User Manual Appendix 14 L Tell remote radio to listen to all packets on specified frame Command general description Addressee is a local radio or a remote radio Remote Command format 0xDD 0x00 0x05 0x00 0x4C 0x 0x 0x 0xNN Ox Ox Ox Destination radio s 3 byte address Frame number in hex format Command example If e the Delimiter on the local radio where th
42. ess data Meaning format User adjustable Delimiter hex value Command length s s s OxLSB Address The LSB of the RAM address which we need to read the D data from iHi data Dummy data hex value one byte only Yes N N i N data from i Ye Ye Note The address could be one from the range below 5800 5900 TDMA Frame Table RAM read command example If e the Delimiter on the local radio where the command is issued is set to 0x77 which will appear in the TDMA Menu as 119 e we need to read 0x58FE location contents e FF being dummy data byte then the command will be 0x770x000x050x000x310x000x580xFEOxFF Output format 0xDD 0x00 0x05 0x00 0x32 0x00 0xMSB Address 0xLSB Address data i whi N o o o o o o o data from mum edad data from Data hex value read form the specified RAM location one byte only Output string example at the local radio If 57 TDMA User Manual Appendix e the Delimiter on the local radio where the command is issued is set to 0x77 which will appear in the TDMA Menu as 119 e 0x20 was stored at the address 0x58FE then the command will be 0x770x000x050x000x310x000x580xFE0x20 58 TDMA User Manual Appendix Network ID and Frequency Key RAM write command format Allows a radio to switch between two networks that have similar settings The radio will receive the command
43. i Ye Ye Note The address could be one from the list below 0x0D81 0x0D82 0x0D85 OxOF 40 OxOF73 OXOFFF EEPROM read command example If e the Delimiter on the local radio where the command is issued is set to 0x77 which will appear in the TDMA Menu as 119 e we need to read OxOF2E location contents e FF being dummy data byte then the command will be 0x770x000x050x000x310x000x0F0x2EO0xFF Output format 0xDD 0x00 0x05 0x00 0x31 0x00 0xMSB Address 0xLSB Address data N o o o o o o o the data from mer up ee wo the data from one byte onl Output string example at the local radio If 53 TDMA User Manual Appendix e the Delimiter on the local radio where the command is issued is set to 0x77 which will appear in the TDMA Menu as 119 e 0x20 was stored at the address OxOF2E then the command will be 0x770x000x050x000x310x000x0F0x2E0x20 Reading or Writing to invalid EEPROM locations will have the Output string OxDD 0x00 0x02 0x00 0x31 0x01 54 TDMA User Manual Appendix 3 2 RAM individual address write and read command RAM write command format Command general description Addressee is a local radio or a remote radio Local RAM write command format 0xDD 0x00 0x05 0x00 0x32 0x01 0xMSB Address 0xLSB Address data Meaning format User adjustable Delimiter hex value Command length Write operation Yes
44. ies what slot the function will occur within a specified frame M Upper Nibble Lower Nibble Figure 6 Frame Nibble Explanation 23 TDMA User Manual Programming the Frame Table Note The frame table is laid out in a square fashion because it displays better on the screen The frame table in time is sequential 00 01 02 OE OF 10 11 1F 20 21 etc Upper Nibble Settings 0 A setting of zero 0 assigns the radio to be idle during this frame It is effectively doing nothing but listening in the background The lower nibble is irrelevant and is ignored However any RF commands or data directed to that radio from a radio in packetized mode is received and transferred out the RS 232 output Data broadcast to all is ignored and data received from transparent mode radios is ignored When this is set to one 1 the radio will listen for any radios that transmit within that particular frame The radio will receive the data and send this data to the RS 232 port However if the data is from a packetized radio and the data is addressed to another radio the data is not sent to the RS 232 port A setting of two 2 in a master radio or a slave radio will transmit any data received on the RS 232 port during the assigned frame as long as the lower nibble is set to zero 0 If the radio is to be a submaster master repeater or a repeater slave repeater a setting of two 2 in the upper nibble must be accompanied wi
45. ile link would require a setting of 3 in the Time Delay parameter Adds 2 clock ticks per slot per increment This setting effectively adds two bytes per slot per increment Time for 2 bytes 138us times the speed of light gives a distance of 25 89 miles Since this is round trip dividing by 2 gives 13 miles TDMA User Manual TDMA Related Parameters TDMA Related Parameters Following is a list of user selectable options in other than TDMA menu which define TDMA system operation and functionality Set Baud Rate Manu Radio Parameters Menu 3 RF Data Rate The RF Data Rate parameter should be set to 3 All factory testing specs and timing are based on an RF data rate of 3 Note A network will work at an RF data rate of 2 but the timing changes and the maximum data packet size changes from 240 to approximately 180 bytes 8 Retry Timeout The value entered here is used to determine how long a radio can not hear the network before dropping the link to the network This parameter is the number of master frames that can be missed before the radio drops the link For example when you leave the coverage area and the radio can no longer hear the master or a submaster then it starts counting the master frames or frame casings When it reaches the number set here the radio drops the link and tries to re aquire the network The default is 255 Note This can cause delays of 1 minute and more easily depending upon
46. imiter on the local radio where the command is issued is set to 0x77 which will appear in the TDMA Menu as 119 e the remote radio s serial number is 900 1234 0x890x590x1 2 then the output string will be 0x770x890x590x120x0A0x010x020x030x040x050x060x070x080x090x0A Note When the destination radio is addressed the radio will receive the message even if it was programmed to do nothing for that frame If the destination address is all radios hex address FF FF FF only the radios programmed to listen will receive the message if there is a good link Note When the fourth byte is set to zero the frame number specified in byte 9 is the index into the epoch A further discussion is coming soon When the fourth byte is set to one the frame number specified in byte 9 is the index into the frame casing Allowable entries are 1 slave frames per master frame setting Sending zero will result in nothing and sending a value higher than slave frames per master frame will lock up the local port indefinitely 82 TDMA User Manual Appendix 13 H Who s out there command Command general description Each radio echoes the response out the local port as well as across the TDMA network back to the requesting unit Addressee is a local radio or a remote radio Remote Command format 0xDD 0x00 0x05 0x00 0x48 0xFFOxFFOxFF 0xFO N e OxFFOxFFOxFF Destination radio s 3 byte address OXFFOxFFOxFF m
47. ings TDMA Frame Table and Frequency table 7 Bulk load of frame table Tell local radio to respond with its signal quality packet 19 0x63 Getradio s firmware version Commands executed on the remote radio only Commandcode Acton Sd Tell remote radio to respond with its signal quality packet on specified frame E Tell remote radio to transmit a status packet on specified frame radios on a specified frame 19 OxDD Ox 0x 0x 0x00 d Send data packet to a specified radio or broadcast ata packet length data 29 TDMA User Manual Operation Modes Note Refer to the Appendix A for detailed commands descriptions There are two types of data messages assigned and immediate If the address field of the message is set to the sending radio s address the message is called an assigned message An assigned message is stored by the radio until a new assigned message is received on its serial port An assigned message is then broadcast by the radio during the frame that is designated for transmitting However if the radio has other messages to broadcast those messages are transmitted instead The second type of data message is an immediate message An immediate message is broadcast in a frame selected by the radio If the radio is a master radio the data is broadcast in the next master frame slot If the radio is a slave radio the data is broadcast on a randomly selected slave frame between th
48. io Local Note Disconnect message is not available on the master Output format at the local radio Disconnect 0xDD 0x00 0x02 0x00 0x44 0x o Ox If this location has 00 in it then the radio has being just N turned on or the radio lost sync to the master for the first time If there is a number in this location that is the number of times the slave or submaster has lost sync and disconnected from the network to require a sync signal Output string example at the local radio If e the Delimiter on the local radio where the command is issued is set to 0x77 which will appear in the TDMA Menu as 119 e the local radio just power up then the output string will be 0x770x000x020x000x440x00 If e the Delimiter on the local radio where the command is issued is set to 0x77 which will appear in the TDMA Menu as 119 e the local radio has been powered up for a long time and had 20 0x14 disconnects during this time then the output string will be 0x770x000x020x000x440x14 Output format at the local radio Connect OxDD 0x00 0x01 0x00 0x45 Meaning format User adjustable Delimiter hex value 61 TDMA User Manual Appendix Command length 0x45 Command code the submaster or slave has found a synch No signal from the master and has connected to the network Output string example at the local radio If e the Delimiter on the local radio where the command is issued
49. ions Definitions Slot A slot is a period of time in which a single message is transmitted received or repeated by a particular radio The duration of this message is a user defined setting and may range from 8 to 240 bytes A radio which is assigned a particular slot will always transmit at least a header packet regardless of data It takes 1 to 16 slots to make a frame refer to Figure 1 There are two types of slots master slot and slave slot All slave slots are the same size The master slot and slave slot byte sizes do not need to be identical Master slot The Master slot occurs as the very first slot of a master frame The maximum number of data bytes within this slot can be set differently than a slave s slot The number of bytes can range from 8 to 240 bytes A master radio will always transmit at least a header packet regardless of data present in the first slot of a master frame System slot A system slot is a special slot that occurs before the master frame It is transparent to the user and is only used by the system to allow the radios to finish processing before proceeding to the next frame casing The system slot can also be used to insert a small amount of dead time to make the overall timing within the network match some external clock f used to extend the time for timing issues there will not be any radios transmitting during this slot Frame A frame is a grouping of 1 to 16 slots All slots within a frame a
50. ions will have the Output string 0xDD 0x00 0x02 0x00 0x61 0x01 70 TDMA User Manual Appendix 8 b Tell local radio to respond with its signal quality packet Command general description Addressee is a local radio or a remote radio Local Command format OxDD 0x00 0x01 0x00 0x62 Meaning format User adjustable OXdd Delimiter byte hex value S Command length Command example If e the Delimiter on the local radio is set to 0x77 which will appear in the TDMA Menu as 119 then the command will be 0x770x000x010x000x62 Output format at the local radio OxDD 0x00 0x01 quality packet length 0x00 0x62 data Meaning format User adjustable Delimiter byte hex value of the local radio 1 plus number of bytes in the quality packet in hex format packet length For example if the quality packet includes 4 bytes of data then this location will be 0x05 No o 0x62 1 Commandcode 0 M iHHHiE data The actual quality packet data in hex format Please see N Note below for more information about this item Note The quality packet always consists of n 2 submasters 1 1 bytes of data The format of these data bytes is as follow e ifthere are no submasters in the network DataByte1 DataByte2 DataByte3 e if there are one or more submasters in the network DataByte1 DataByte2 DataByte3 DataByte 2 i 2 DataByte 2 i 3 71 TDMA U
51. is set to 0x77 which will appear in the TDMA Menu as 119 e the local radio just power up then the output string will be 0x770x000x010x000x45 62 TDMA User Manual Appendix 5 S Tell local radio to go into the setup mode Command general description Addressee is a local radio or a remote radio Local Command format OxDD 0x00 0x01 0x00 0x53 Meaning format User adjustable Delimiter byte hex value es Command length Note After the command will be executed the RS232 baud rate in setup mode will be the same as it was before the setup Command example 0x770x000x010x000x53 Output format at the local radio Radio returns its Main Menu text 63 TDMA User Manual Appendix 6 Bulk load of EEPROM TDMA Settings TDMA Frame Table and Frequency table Write command format Command general description Addressee is a local radio or a remote radio Local After reception of program command the radio will reset and assuming no network sensitive parameters were changed re acquire the network Write command format OxDD 0x00 0x4 data size 0x00 0x60 0x01 0xMSB Address 0xLSB Address data Field name Meaning format User adjustable OxDD Delimiter hex value 0x04 data size 0x60 0x01 OxMSB Address OxLSB Address it data data hex value to be loaded starting from Address specified above Note The address could be one from the list below E25 F2E TDMA
52. iter characters inside the data packet This command is suitable for random binary data Command format 0xDD 0x00 0x05 data size OxEC 0x46 0x 0x 0x 0xNN data Meaning format User adjustable Delimiter hex value 0x05 0xdata size Number of data bytes plus 5 in hex format For example if the command includes 4 bytes of data in the end then this location should be 0x09 Ox Ox Ox Destination radio s 3 byte address Frame number to send command on data The actual data being sent in hex format See note Command example e the Delimiter on the local radio is set to 0x77 which will appear in the TDMA Menu as 119 e the remote radio s serial number is 900 1234 0x890x590x1 2 e the frame number will need to used to send data is 05 e the data needs to be sent is 123456789A then the command will be 0x770x000x0E0x000x460x890x590x120x050x010x020x030x040x050x060x070x080x090x0A Output format at the remote radio OxDD Ox 0x 0x 0xdata size data Meaning format User adjustable Delimiter hex value No Ox Ox Ox Sending radio s 3 byte address No Oxdata size Number of data bytes in hex format For example if the No command includes 4 bytes of data in the end then this location should be 0x04 iHHHE data The actual data being sent in hex format No 81 TDMA User Manual Appendix Output string example at the remote radio If e the Del
53. k Red Outofsync with network CDLine i a e a o o De Asserted_ When radio is receiving data from the network Operation in Transparent Mode There are two different data types immediate and assigned If the data type is immediate the radio will transmit one time only on a random selected slave frame after the next frame casing If the data type is assigned data the radio will transmit the 28 TDMA User Manual Operation Modes message in its buffer during the assigned slot New data received from the RS 232 port will delete any previous data in the radios RS 232 buffer Operation in Packetized Mode All data sent in and out of the RS 232 port begins with a header packet All data packets must be less than or equal to the maximum data size set up initially in the TDMA setup menu for Slave Data Packet Size in Bytes and Master Data Size in Bytes The header packet is not considered part of the data See Table 3 for a listing of all of the packetized commands Note All dynamic allocations of frame function are stored in non volatile RAM Any loss of power will cause all changes to reset back to the original setup parameters set by the user Table 4 Packetized Mode Commands Commands executed on the local radio only Commandcode tion UNE 0 ual Disconnect Message needs to be set for this feature 5 0x53 Tell local radio to go into the setup mode Bulk load of TDMA Sett
54. ll slots until it hears a valid packet Setting to 11 12 has no effect and is not recommended This setting tells the radio during this frame to transmit data which was received from the RS 232 port and transmit this data on slot zero 0 of that frame The x value refers to the slot number in which data or command is repeated which was heard the slot before from a transmitting master slave or another repeater The data which is heard and repeated is not sent to the RS 232 port The x value refers to the slot number in which data or command is repeated which was heard the slot before from a transmitting master slave or another repeater The data which is heard and repeated is sent to the RS 232 port This setting is useful if a slave is needed to be used as a submaster or a repeater Table2 Frame Table Settings 1 15 A lower nibble setting of one 1 to fifteen 15 refers to the slot in which a process takes place A setting greater then zero in the lower nibble is used for radios which have been designated to repeat data that it hears Note The entries in the frame table are to be entered in hexadecimal Therefore the reference made in the lower nibble section referencing the lower nibble 1 15 should have entries in the frame table consisting of 1 2 3 4 5 6 7 8 9 A B C D E or F hexadecimal numbers Note A repeater or submaster will repeat the data from the first slot that that radio hears prior
55. me The frame table for slave 38 is shown in table 8 47 TDMA User Manual Examples of TDMA Networks Table 9 Example 4 Slave 38 Frame Table The frame table of slave 38 showing in bold the frame where it transmits and listens Listens on frame 00 0 and transmits on frame 20 6 L0 1 2 3 4 5 6 7 8 9 A B C DJj E r oo 10 oo oo oo oo oo oo OO OO OO OO OO OO OO OO OO 10 00 00 00 oo oo oo oo OO OO OO OO OO OO OO OO OO 20 00 oo oo oo oo OO 20 OO OO OO OO OO OO OO OO OO 30 oo oo oo oo oo OO OO OO OO OO OO OO OO OO OO OO Table 10 Example 4 Actual Transmission 48 TDMA User Manual Appendix Appendix A Packetized Commands Description General Rules Definitions applied to all of the commands and used in this document There are two command types local and remote The remote command is addressed to one or more remote radios The local command is addressed to a local radio If the local radio heard the command it will evaluate it and in some cases respond back to the RS232 port with a string indicating that the command took effect Any data or command in the packetized mode must begin with a Delimiter The Delimiter is a byte of data specified in the TDMA Parameters Menu under Packet Delimiter Character It could be anything from 0 to 255 Please note that 0 and
56. mming the Frame Table The frame table is used to specify the function of the radio during each frame The radio can be programmed to transmit receive repeat or do nothing The Frame Table is accessible through the TDMA parameter table By selecting item nine 9 the frame table will display see Figure 4 Each box in the frame table is a frame As you may recall a frame is made up of 1 to 16 slots Refer to Figure 5 for a visual perception 6 7 00 00 oo 007 00 Fag oo oo ooj ooj oof oo OO oof OO OO 00 oof oo 0 oo OO OQ oo oof oo oof oo oof oof oof OO 00 00 00 00 oo oof oosa oo oo oof oo OO oof OO OO 00 oo oo Yoo oo oo ooj ooj oo ooj oo oo oo OO oo oo 1 to 16 slots equals a frame i 12 3 4 Ss 7 A 15 Figure 5 Slots in the Frame Table Frame location 0x04h has been expanded to give a visual representation of the slots contained in a frame From what is seen in Figure 5 the entries in the frame table all have a value of 00 Unless we change these values the radio at this time is programmed to do nothing The values for programming the frame table for the radio modem consist of two values which are referred to as an upper nibble and a lower nibble settings The upper nibble Figure 6 sets the function of the radio within the frame and the lower nibble sets the slot position for that function to happen Upper nibble sets the radio s function and the lower nibble specif
57. mount of time necessary to process data before the beginning of the next frame casing Note While many versions of firmware will allow the system slot to be set to less than 8 the radio will not work properly unless the system slot is set to at least 8 9 Edit Xmit Receive Frames When this parameter is selected the user will get a Frame table see Figure 4 This frame table needs to be setup by the user with specific parameters which is entry into the individual frame boxes The specific parameters enter into the different frames will indicate whether the radio modem is to be a master submaster repeater a slave or do nothing Enter Frame Number esc returns to main menu __ Each frame is represented as one entry in the table To enter a value in a frame you would first enter the first value of the line number on the left row and combine it with the number on the top column For example the bold 00 value frame is accessible by typing 87 The frame below if would be 97 and so on Figure 4 TDMA Frame Table TDMA User Manual TDMA Setup Parameters A Transparent Data Operation 0 1 This parameter is valid for the transparent operation mode only This parameter assigns the type of data for the radio The type of data can be either assigned data or immediate A value of zero 0 is for assigned data and a one 1 is for immediate Assigned data is the most commonly used data type Assigned Data The radio will transmi
58. mple If e the Delimiter on the local radio master is set to 0x77 which will appear in the TDMA Menu as 119 e the addressee s serial number is 900 1234 0x890x590x12 e the frame number will need to used for the 900 1234 radio s response is 05 then the command will be 0x770x000x050x000x370x890x590x1 20x05 After this command will be received by the radio 900 1234 it will send its quality packet on the frame 05 Output format at the master radio 0xDD 0x00 0x04 quality packet length 0x00 0x37 0x Ox 0x data Meaning format User adjustable 76 TDMA User Manual Appendix Delimiter byte hex value of the addressee 0x04 quality 4 plus number of bytes in the quality packet in hex format No For example if the quality packet includes 3 bytes of data m then this location will be 0x07 Ox Ox Ox Addressee s 3 byte address data The actual quality packet data in hex format Note The quality packet always consists of n 2 submasters 1 1 bytes of data The format of these data bytes is as follow e if there are no submasters in the network DataByte1 DataByte2 DataByte3 e if there are one or more submasters in the network DataByte1 DataByte2 DataByte3 DataByte 2 i 2 DataByte 2 i 3 where i 1 2 3 4 is the number of submasters Table below shows DataBytes contents DataByte1 The average noise level at addressee radio DataByte2
59. number of slave frames The slave frame functions can vary from frame casing to frame casing as long as the total number of these frames do not vary Figure 3 shows an example of a frame casing Epoch Frame Casing 1 Frame Casing Maste Slave Slave Maste Slave Slave In Frame Frame T Frame Frame Figure 3 Epoch disection Each Frame casing starts with a master frame followed by slave frames One or more frame casing makes up an Epoch Epoch TDMA User Manual Definitions An Epoch is the period in which an integral multiple of master frames is transmitted before everything is repeated An epoch can be as little as 1 frame casing or as many as 255 frame casings There can be no more than 255 slave frames in an epoch The total number of frames in an epoch is equal to the number of master frames plus the number of master frames multiplied by the number of slave frames Alternatively the total number of frames in an epoch is equal to the number of frames during a frame casing multiplied by the number of master frames See Figure 3 for an example of an epoch consisting of two frame casings Master The master is the radio used within the TDMA network for synchronization Only one radio within the network can be assigned to be a master Every radio within the network must hear the synchronization signal either directly or through a submaster The master always transmits on the first slot of a master frame The master can also be a slave or
60. o in general This parameter does not make any difference on the functionality of the radio in general but it is very important for the packetized mode operation We will set it arbitrarily to 99 0x63 or c The Transparent Operation is going to be set to zero 0 for data to be assigned Setting this parameter to assigned means the data is sent during the assigned transmit frame The next parameter Frame Table Reset on Disconnect refers to the original frame table setup Let s say during the operation of our network we decided to change the transfer frame of one of our slave to another frame by using local or remote commands By setting Frame Table Reset on Disconnect to one 1 the table will be restored to the original setting if the radio disconnects from hearing the master directly or indirectly The End of Data Character in our example is set to 255 which means there is no end of data character The next parameter which needs to be set is Overwrite Assign Buffer f this parameter is set to zero 0 and our timing is off our data could be overwritten before we send the data For our example this setting is set to one 1 Therefore our data will not be overwritten until we have transferred it Step 9 The last parameter to be set is Edit Xmit Heceive Frames For our example Radio A is the master station Radio B C D and E are slaves and Radio B is acting as a submaster and repeater for the network 37 TDMA User
61. on frame 04 slot 00 Radio E transmission Warning note Please note that if Radio C will have 32 in its frame 00 and Radio D will have 31 in its frame 00 the system will not function because Radio D will not be able to re transmit direct master s transmissions So the Radio D and Radio E will not be able to synch up to the master in this case Changing the contents of frame 04 on Radio C from 22 to 21 and at the same time changing the contents of frame 04 on Radio D from 21 to 22 will cause Radio E messages being delivered only to Radio D Radio E There are no changes being done to the frame table of this radio 42 TDMA User Manual Examples of TDMA Networks 43 Customization note The flexibility of the frame table and TDMA system features allow the user to add one or more listeners to the system Listeners will not need to have a dedicated frame assigned to them and will simply act as control points If listener will be installed somewhere where it can hear transmission from Radio C then setting its frame table with all 10 in frames 00 through 04 will allow it to hear all of the transmissions between the radios in the system without interfering with them TDMA User Manual Examples of TDMA Networks Example 3 Note The purpose of this example is to show how to add one more frame casing to the system given in Example 1 and what effect it will have on the system performances From the
62. point Menu 19 1 Master Packet Repeat 19 6 Network ID 20 8 MultiMasterSynch 20 9 1 PPS Enable Delay 20 Programming the Frame Table 22 Upper Nibble Settings 23 Lower Nibble Settings 23 Master Frame Frame 00 0 26 Operation Modes 27 Operation in Transparent Mode 27 Operation in Packetized Mode 28 Network Acquisition 30 Epoch Timing 30 Examples of TDMA Networks 32 Example 1 32 TDMA User Manual Example 2 39 Example 3 43 Example 4 45 Appendix A Packetized Commands 47 Description 47 TDMA Packetized Commands 48 1 0 Tell local radio to return its radio ID 48 2 1 EEPROM individual address write and read command 49 3 2 RAM individual address write and read command 53 4 D Disconnect and Connect status message 59 5 S Tell local radio to go into the setup mode 61 6 Bulk load of EEPROM TDMA Settings TDMA Frame Table and Frequency table 62 7 a Bulk load of frame table into RAM 66 8 b Tell local radio to respond with its signal quality packet 68 9 c Get radio s firmware version number 71 10 7 Tell remote radio to respond with its signal quality packet on specified frame 73 11 B Tell remote radio to transmit a status packet on specified frame 76 12 F Special Data Packet command 78 13 H Who s out there command 80 14 L Tell remote radio to listen to all packets on specified frame 81 15 N Tell remote
63. ppendix 16 R Tell remote radio to become a repeater submaster Command general description Addressee is a local radio or a remote radio Remote Command format Tell remote radio to become a repeater 0xDD 0x00 0x06 0x00 0x52 0x 0x 0x 0xNN 0xSS or tell remote radio to become a submaster 0xDD 0x00 0x06 0x00 0x52 0x 0x 0x 0x00 0xSS o o Note OxNN is a frame number and OxSS is a slot number to be used by the specified radio to repeat messages is hears within OxNN frame on the slots before OxSS es es es Command example If e The Delimiter on the local radio is set to 0x77 which will appear in the TDMA Menu as 119 e f remote radio s serial number is 900 1234 0x890x590x12 Then the command will be Tell remote radio 900 1234 to become a repeater 0x770x000x060x000x520x890x590x120x020x01 After this command will be received by the radio 900 1234 its RAM copy of the frame table will have a new entry in the frame number 02 which is 21 Note after the power will be recycled on the radio 900 1234 the contents of the frame number 02 will be re stored back to the value viewable from the TDMA Menu option Edit Xmit Rcv Frames Tell remote radio 900 1234 to become a submaster 0x770x000x060x000x520x890x590x120x000x01 86 TDMA User Manual Appendix After this command will be received by the radio 900 1234 its RAM copy of the frame table will have a new ent
64. process it and drop the link Then the radio will attempt to link to a network with the new Frequency Key and Network ID This option was added in firmware versions DGR 5 85 DGMR 1 85 Frame Table Reset On Disconnect must be disabled as radio will change the parameters disconnect and re acquire the network or new network 0xDD 0x00 0x05 0x00 0x32 0x03 0x58 0xFF 0xNN 0x05 Commandiength CN 0x32 Commandcode TN No Dummy Byte NER C HEN Frequency Key Network ID No No No No Yes S Note The Frequency Key should be between 00 and 0E The Network ID should be between 00 and FF Output format 0xDD 0x00 0x05 0x00 0x32 0x03 0xFF O0xNN OxXX N o o o o o o o OxNN_ Network IDsetinRAM Y M Network ID and Frequency Key RAM write command example If e the Delimiter on the local radio where the command is issued is set to 0x77 which will appear in the TDMA Menu as 119 e The frequency key should be set to 6 e The network ID should be set to 42 then the command will be 0x770x000x050x000x320x030x580x060x2A 59 TDMA User Manual Appendix Output string example at the local radio 0x770x000x050x000x320x030x060x2A0xAA TDMA User Manual Appendix 4 D Disconnect and Connect status message The TDMA parameter Disconnect Message needs to be set for this feature Command general description Addressee is a local radio or a remote rad
65. put string will be 0x770x000x040x000x620x2D0x5F0x57 If the local radio is the master the last two bytes 0x5F and 0x57 above will be 0x00 and 0x00 72 the delimiter on the local radio is set to 0x77 which will appear in the TDMA menu as 119 there are two submasters in the system Number of SubMasters in the TDMA menu is set to 2 the local radio is the first submaster its frame table has 31 or 21 in the frame 00 RadioStatistics Menu on the local radios reads 29 for average noise level Please note that actual average noise value returned by the local radio will be greater than shown in the RadioStatistics Menu by 16 29 16 45 or Ox1D 0x10 Ox2D the percentage of master packets successfully decoded by the local radio is 95 0x5F the average signal level measured by local radio during master s transmission frame 00 slot 0 is 87 0x57 TDMA User Manual Appendix the percentage of packets sent from submaster 2 and successfully decoded by the local radio is 99 0x63 the average signal level measured by local radio during transmission of submaster 2 frame 00 slot 2 is 85 0x55 Then the output string will be 0x770x000x080x000x620x2D0x5F0x570x000x000x630x55 positions in the packet which correspond to decode success and average signal level of the radio whose signal quality packet was requested the first submaster in our case Notes 73 e The packet
66. r frame as a repeater during the frame assigned for Radio E transmission and as a slave during its own dedicated frame Therefore the Number of Submasters in this case should be set to 2 Radio C and Radio D and the S ave Repeaters per Frame will also need to be set to 2 Radio C and Radio D Skipping Steps 1 through 8 from the previous Example let s see how the frame tables will need to be changed to accommodate the network topology difference Following is analysis of the given frame tables for each radio and the ways of their improvement customization Fionre 13 Fyamnle 2 Frame Tahle TDMA User Manual Examples of TDMA Networks 0 1 2 3 4 5 6 7 8 9 A B C D E F 00 20 10 10 10 10 O0 oo oo 00 oo 00 oo 00 00 foo 00 10 00 oo foo co oo oo O0 oo oo oo oo foo OO oo oo OO 20 00 oo oo oo oo oo oo oo oo oo oo oo oo oo oo 00 a Master stations radio frame table setup Master slot 00 0 0 1 2 3 4 5 6 7 8 9 A B C D E F 00 31 20 22 22 22 oo 00 oo 00 00 00 00 00 oo oo 00 10 00 oo oo co oo oo co oo oo oo oo foo OO oo 00 OO 20 Loo 00 oo oo 00 00 oo oo 00 00 oo oo oo oo oo 00 b Submaster Repeater and Slave refer to Radio C 0 1 2 3 4 5 6 7 8 9 A B C D E F 00 10 oo 20 oo oo oo oo oo oo oo oo oo OO oo oo 00 10 00 oo oo oo oo oo oo oo oo oo oo 00 oo oo 00 oo 20
67. re the same size A master frame and a slave frame are the only type of frames Refer to Figure 2 The frame is used to assign a specific task to a radio A task can consist of telling the radio to transmit listen do nothing or repeat Figure 2 Frame Dissection TDMA User Manual Definitions Master frame The frame number 0 is a master frame During this frame there can be up to 15 repeating slots each of which is the same size as the master slot A master frame occurs every 1 to 15 frames The master and submasters use the master frame to synchronize the timing of the entire network and to send data packets Every radio within the network must be able to hear the master or any submaster to remain active within the system Slave frame A slave frame is a fixed number of slots that follows the master frame Every frame except the one master frame is termed a slave frame There can be up to 15 repeating slots within a slave frame Given the fact that all of the radios in the network synchronized to the master a radio transmitting in a repeating slot need not hear the originating slave radio as long as it hears one repeater before it Frame casing A frame casing consists of one master and one to fifteen slave frames The master frame is always the first frame of a frame casing and is always followed by at least one slave frame There can be different frame casings in the system but it must always have the same master frame and the same
68. ry in the frame number 00 which is 31 Note after the power will be recycled on the radio 900 1234 the contents of the frame number 00 will be re stored back to the value viewable from the TDMA Menu option Edit Xmit Rcv Frames 87 TDMA User Manual Appendix 17 T Tell remote radio to transmit on specified frame Command general description Addressee is a local radio or a remote radio Remote Command format 0xDD 0x00 0x05 0x00 0x54 0x 0x 0x 0xNN Meaning format User adjustable Delimiter byte hex value Yes O Command length No Ox t Oxdit OXHH Destination radio s 3 byte address Yes Frame number in hex format Ye N N Ye e S o o S S Command example If e The Delimiter on the local radio is set to 0x77 which will appear in the TDMA Menu as 119 e f remote radio s serial number is 900 1234 0x890x590x12 Then the command will be 0x770x000x050x000x540x890x590x120x02 After this command will be received by the radio 900 1234 its RAM copy of the frame table will have a new entry in the frame number 02 which is 20 Note after the power will be recycled on the radio 900 1234 the contents of the frame number 02 will be re stored back to the value viewable from the TDMA Menu option Edit Xmit Rcv Frames 88 TDMA User Manual Appendix 18 m Gather routing information from source radio to destination radio Comm
69. s per Master Frame 5 Master Frames in Epoch 10 The frame table is assigned such that 00 0 is the master frame 00 1 is slave 1 00 2 is slave 2 continuing to 30 2 being slave 50 82h 50d as shown in table 6 When set up this way the sequence will be the system slot the master frame and then five slave frames Since the Master Frames in Epoch is greater than one it will keep its place and then transmit the next 5 slave frames the next time The actual transmission sequence of the system is shown in table 9 Table 7 Example 4 Radio Frames Showing how the frames are assigned to different radios 0 q 1 E 1 E42 3s 4 s s 7 81 3g 4 1B5 cej ltg t 00 Master S1 s2 s3 s4 ss se s7 se so S10 TE siz sia sid s15 10 s16 siz s18 S19 S20 S21 S22 S23 S24 S25 S26 S27 S28 S29 S30 S31 20 S32 S33 S34 S35 S36 S37 S38 S39 S40 S41 S42 S43 S44 S45 S46 S47 30 S48 s49 S50 NA NA NA NA NA NA NA NA NA NA NA NA MA The frame table of the master radio should be set to transmit in frame 00 0 and listen in the other frames that are used This is shown in table 7 Table 8 Example 4 Master Frame Table The frame table of the master radio showing in bold the frame where it transmits Frames 30 3 through 30 F are unused Each individual radio should be set to listen to the master frame 00 0 and transmit on its specified fra
70. ser Manual Appendix where i 1 2 3 4 is the number of submasters Table below shows DataBytes contents DataByte1 The average noise level at the local radio DataByte2 Percentage of packets sent from the master which were successfully decoded by the local radio during the frame 00 slot 0 DataByte3 Average signal level measured by the local radio during master s transmission during the frame 00 slot 0 DataByte 2 i 2 Percentage of packets sent from submaster i which were successfully decoded by the local radio during the frame 00 slot i DataByte 2 i 3 Average signal level measured by local radio during submasters i transmission during the frame 00 slot i Output string example at the local radio the Delimiter on the local radio is set to 0x77 which will appear in the TDMA menu as 119 there are no submasters in the system Number of SubMaster in the TDMA menu is set to 0 the local radio is a slave RadioStatistics Menu on the local radios reads 29 for average noise level Please note that actual average noise value returned by the local radio will be greater than shown in the RadioStatistics by 16 29 16 45 or Ox1D 0x10 Ox2D the percentage of master packets successfully decoded by the local radio is 95 0x5F the average signal level measured by local radio during master s transmission frame 00 slot 0 is 87 0x57 Then the out
71. settings including TDMA frame table F74 FFD Frequency hop table Note For 225 400 MHz radios this hop table starts at F74 please refer to 225 400 MHz radios EEPROM Value to Frequency Calculations for more details Write command example If e the Delimiter on the local radio is set to 0x77 which will appear in the TDMA Menu as 119 e we need to store 0x02 at E26 and 0x12 at E27 then the command will be 0x770x000x060x000x600x010x0E0x250x020x12 Output format at the local radio 0xDD 0x00 0x4 data size 0x00 0x60 0x01 0xMSB Address 0xLSB Address data Output string example at the local radio If TDMA User Manual Appendix e the Delimiter on the local radio is set to 0x77 which will appear in the TDMA Menu as 119 e 0x02 was stored at OXOE26 and 0x12 was stared at 0x0E27 then the command will be 0x770x000x060x000x600x010x0E0x250x020x12 65 TDMA User Manual Appendix Read command format OxDD 0x00 0x6 0x00 0x60 0x00 0xStart MSB address OxStart LSB address 0OxEnd MSB address 0xEnd LSB address Ee ea 15 Address Stop reading at this address LSB of this address Address Note The address could be one from the list below E25 F2E TDMA settings including TDMA frame table F74 FFD Frequency hop table Maximum allowable length 140 EEPROM addresses Note For 225 400 MHz radios this hop table starts at F74 please refer to 225 400 MHz radios EEPROM Valu
72. si Js Js is 75 Js uo m a e tn o s2 34 4 a fe is ee fou r 53 35 5 5 fe f ue fes p pas s 54 fis 7 fv jue es 46 6e pss qa tT ue 7 fw is y1 o r se s Js J ofsa Jx Jus s jos es s7 Js fo um y fy us m J 5 229 r ss dsa m 7 z is sa 250 FA Ba 93 TDMA User Manual Appendix 94 TDMA User Manual Appendix Needs to be added e CD and CTS timings e Test commands 95 TDMA User Manual Appendix Appendix C Firmware Tables FGR Firmware 2 26 03 04 2003 Initial release 2 27 04 28 2003 Added remote LED functionality 2 30 07 28 2003 Added version of special data packet that references the frame casing instead of the epoch 09 26 2003 DGR Firmware 09 10 2002 Added version of Ram write command to load network ID and frequency key with one command 5 87 03 02 2003 5 88 08 04 2003 Added version of special data packet that references the frame casing instead of the M DGMR Firmware 1 86 11 23 2002 Added version of Ram write command to load network ID and frequency key with one command 96
73. ssee is set to 0x77 which will appear in the TDMA menu as 119 the addressee has serial number 900 1234 0x890x590x1 2 there are two submasters in the system Number of SubMasters in the TDMA menu is set to 2 the addressee is the second submaster RadioStatistics Menu on the addressee reads 29 for average noise level Please note that actual average noise value returned by the addressee will be greater than shown in the RadioStatistics Menu by 16 29 16 45 or Ox1D 0x10 Ox2D the percentage of master packets successfully decoded by the addressee is 95 0x5F the average signal level measured by addressee during master s transmission frame 00 slot 0 is 87 0x57 the percentage of packets sent from submaster 2 and successfully decoded by the addressee is 99 0x63 the average signal level measured by addressee during transmission of submaster 2 frame 00 slot 2 is 85 0x55 Then the output string will be 0x770x000x0B0x000x370x890x590x120x2D0x5F0x570x630x550x000x00 positions in the packet which correspond to decode success and average signal level of the radio whose signal quality packet was requested the second submaster in this case Notes 78 e The packet will include zeros in the position of the radio whose packet was requested e The average signal level from x radio is only updated when x radio is heard Therefore if x radio is turned off its average signal level will still
74. t a packet on the first frame in the next frame casing that has a 20 transmit mark If this radio does not have a 20 in it s frame table then it will never transmit the data Immediate Data The radio will randomly pick a frame from the next casing and transmit its data on that frame The radio does not care if any other radios are set to transmit during this frame Note Please note that in the packetized mode selection between the assigned or immediate data can be done by selecting an appropriate Send data packet to a specific radio or broadcast command format only refer to Appendix A for more details and command format B Frame Table Reset on Disconnect 0 1 This parameter controls whether or not a temporary frame table should be reset back to the original frame table if radio looses the synch to the master A setting of zero 0 will not reset back to the original setup on disconnect A setting of one 1 will reset the frame table to the original frame table when the radio disconnects Note If the radio loses power the temporary frame table will be lost due to being stored in non volatile RAM Next time radio turned on the original frame table will be copied to the temporary frame table C Disconnect Message 0 1 This parameter controls whether or not a disconnect message is transferred out of the RS 232 port whenever the radio disconnects A setting of zero 0 gives no message on disconnect A setting of a on
75. t or Point to Multipoint GrandMaster operation refer to the FreeWave Grand Master Mode document for more information However in the TDMA mode there are some additional RS232 lines wiring involved in order to assure a proper MultiMasterSync functionality A complete setup procedure for TDMA MultiMasterSynch may be found in the TDMA Networks with co located masters Setup instructions please contact FreeWave Technologies regarding this document 9 1 PPS Enable Delay Note This feature is available for the radios with the serial numbers 571 0000 and above and the f w version 5 59y and higher Note This feature is only available in packetized mode Activating this parameter allows ndependent synchronization of all radios in a TDMA network to a time stamp generated by an external device and a 1 PPS 20 TDMA User Manual TDMA Related Parameters signal generated by a GPS receiver In some applications it might be beneficial because in this case every radio in the network does not need to hear master s or submaster s transmissions This simplifies the network topology design and allows for greater mobility of all radios within the network Specifications and Limitations 1 The radio must be supplied with a one PPS pulse on the DTR pin The rising edge of the 1 PPS will be used as a one second timing reference and must have an accuracy of 500 nsec 2 A new time stamp packet has been defined and must be sent to the r
76. th a lower nibble pointing to a slot other than slot zero 0 The radio which is set to be a repeater or submaster does not output the data to the serial port A setting of three 3 in the upper nibble will repeat what radio hears on slot zero The lower nibble determines what slot the message will be repeated on This setting of three 3 also allows data which radio received to be sent out the RS 232 port This setting is useful if you need a slave to act as a repeater Lower Nibble Settings The lower nibble sets the slot position within the frame which a radio will perform a specific function The upper nibble is the main determinant in what the radio will actually do in a particular frame The following gives the rules for the lower nibble settings 2A TDMA User Manual Programming the Frame Table 0 Azero 0 nibble setting is only allowed with an upper nibble setting of a zero 0 one 1 or two 2 The zero 0 nibble varies in meaning depending on the upper nibble setting See Table 2 for different meanings Meanings of Different Frame Settings This setting tells the radio during this frame to do nothing however if the radio receives a packetized command from the master the radio will send it out the RS 232 port 10 This setting tells the radio during this frame to listen and send whatever it hears to the RS 232 port as long as this data is not addressed to another radio using packetized mode A radio will listen on a
77. the complete sequence of slots frames and frame casings that continually cycle Figure 1 illustrates this concept Master Frame 1 to 16 slots Slave Frame 1 1 to 16 slots Slave Frame 15 1 to 16 slots Figure 1 Frame Casing One Master Frame with 1 to 15 Slave Frames makes one frame casing One or more of these frame casings make an epoch I The design goal of the TDMA protocol was to give the user a maximum amount of optimization for the application This is accomplished by having a transparent mode and packetized mode Packetized mode requires the use of a header packet to direct messages or commands to a specific radio or to all radios Packetized mode can be used in a poll environment and has no limit on the number of slave radios in the network Radios specifically addressed in the header packet will send the received information TDMA User Manual FreeWave TDMA general description out the RS 232 port If all radios have been addressed by doing a broadcast all all radios listening will receive information and will transfer it to the RS 232 port Transparent mode is most commonly used with devices which are not capable of generating header packets Therefore all data received from the RS 232 port is broadcasted to every listening radio When the data is received by a radio operating in transparent mode he data sent to the RS 232 port does not have a header packet associated with the data Each slave radio has a frame assigned to
78. the master station is going to be setup in packetized mode The TDMA Data Communication Mode setting for our master station will have a setting of one 1 and the repeater and the slave radios will have a setting of zero 0 Table 5 Example 1 Settings FreeW ave HyperT erminal Dial ola ele e TDMA Parameters TDMA DataCommunications Mode 1 Slave Data Packet Size 8 240 2 MasterData Packet Size 8 240 3 Number of SubMasters 0 15 4 Slave Frames per Master Frame 1 15 5 Slave Repeaters per Frame 0 15 6 Master Frames in Epoch 1 63 CL Packet Delimiter Character 0 255 8 System Slot Length 0 255 9 Edit Xmit Rcv Frames A Transparent Data Operation B FrameTable Reset on Disconnect te Disconnect Message D End of Data Character 0 255 E Overwrite Assigned Buffer F Time Delay 0 238 Esc Exit to Main Menu Enter Choice Step 3 The next parameters consist of the Slave Data Packet Size and the Master Data Packet Size This parameter value can be any number between 8 and 240 The Slave Data Packet Size is going to be set to 152 data bytes and the Master Data Packet Size is going to be set to 100 bytes Referring back to the section Epoch Timing we know that it takes 69 444us to send one byte of data Therefore 152 bytes of data to be sent within one 1 slave frame slot would take TDMA User Manual Examples of TDMA Networks slave packet size 69 444us 2 917ms 152 69 444us 2 917ms
79. them in which they are allotted a time to transmit data Therefore the number of slave radios allowed in a transparent environment is limited to 255 However in some applications this number might be higher For example if some of the slaves in the network do not transmit data and only listen to the master A network can be a combination of transparent mode and packetized mode radios One of the most common networks consists of a master radio being setup in packetized mode and the slaves set up in transparent mode This type of setup allows the master to issue commands to the listening slaves Having the slaves in transparent mode allows the user to connect devices that cannot identify themselves by building header packets The FreeWave TDMA network provides a best effort transport meaning that delivered packets are guaranteed to be error free but packets containing errors are discarded No error correction mechanism is implemented in the TDMA network itself All packets must pass a 32 bit CRC check before the packet is sent out the RS232 port Data is guaranteed to be accurate but not guaranteed to be received RS 232 data must be sent to the radio following the state of the CTS line and must be received before the system slot to be transmitted in the following frames Even when there are multiple frames per frame casing for a particular radio all data for that frame casing must be received before the system slot TDMA User Manual Definit
80. this document General info e mail Moreinfo Q freewave com TDMA User Manual Contents About this document General information Revision History How to contact us Contents lii FreeWave TDMA general description 6 Definitions 8 Slot 8 Master slot 8 System slot 8 Frame 8 Master frame 9 Slave frame 9 Frame casing 9 Epoch 9 Master 10 Submaster 10 Slave 10 Slave repeater 10 Assigned data and immediate data 11 Packetized mode 11 Transparent mode 11 Local radio 12 Remote radio 12 Original and temporary frame tables 12 CRC 12 TDMA Setup Parameters 13 0 TDMA Data Communication Mode 0 1 14 1 Slave Data Packet Size in bytes 8 240 14 TDMA User Manual 2 Master Data Packet Size in bytes 8 240 14 3 Number of Submasters 0 15 15 4 Number of Slave Frames per Master Frame 1 15 15 5 Number of Slave Repeaters per Frame 0 15 15 6 Number of Master Frames in Epoch 1 255 15 7 Packet Delimiter Character 0 255 15 8 System Slot Length 8 255 16 9 Edit Xmit Receive Frames 16 A Transparent Data Operation 0 1 17 B Frame Table Reset on Disconnect 0 1 17 C Disconnect Message 0 1 17 D End of Data Character 0 255 18 E Overwrite Assigned Buffer 0 1 18 F Time Delay 0 238 18 TDMA Related Parameters 19 Set Baud Rate Manu 19 Radio Parameters Menu 19 3 RF Data Rate 19 8 Retry Timeout 19 Point to Multi
81. to its assigned transmit slot For example if you have a master with two submasters through which the data must flow consecutively the first submaster will repeat on slot 1 what it heard in slot 0 The second submaster TDMA User Manual Programming the Frame Table 26 who can not hear the master directly will miss the transmission on slot 0 but will hear the transmission on slot 1 and will repeat that on slot 2 However if we have a system where both submasters can hear the master then submaster 1 will repeat what it hears on slot 0 in slot 1 Submaster 2 will listen on slot 0 and if it hears the master s transmission correctly then it will repeat this message on slot 2 If it does not receive the master s transmission properly then it will listen on slot 1 for the repeated message If it receives this message correctly it will repeat this message on slot 2 TDMA User Manual Programming the Frame Table Master Frame Frame 00 0 As you recall from the definition section the master and submaster radios only use Master Frame The master and submaster radios only use the very first frame of the frame table refer to Figure 7 The actual location in the frame table is 00 0 C D E F 20 0800 a 98 904 60100 20 B oe A Es 00 00 oo oof oo oo OO 00 O0 The master frame Only the master radio and the submaster are allowed to use this frame The radio assigned to transmit in this frame is always the master Only one master is
82. ur 4 slaves and one master in our one 1 frame casing Therefore theoretically we can setup the Number of Master Frames in Epoch to be up to 63 255 number of slaves 255 4 63 Due to simplicity of the network that we are trying to configure it makes sense to keep the Number of Master Frames in Epoch at one 1 In some applications the system may require more than 1 frame casing per epoch In this case one would need to relate to the system slot in helping to tune network timing Step 7 35 TDMA User Manual Examples of TDMA Networks The System Slot Length parameter is used to elongate the frame casing timing for time sensitive applications Since we have determined all the necessary parameters for our network we can now determine the amount of time it takes to receive our data in an epoch The following is the calculations of what time it takes to transfer our real time data 1 Slave slot time 152 69 444us 2 917ms 13 472488ms 1 Master slot time 100 69 444us 2 917ms 9 8614ms 1 Slave frame time 13 472488ms 1 Number of repeaters 13 472488ms 2 26 9450ms 1 Master frame time 9 8614ms 1 Number of submasters 9 8614ms 2 19 7228ms Time for all Slaves in 1 frame casing 26 9450ms Number of slave frames per master frame 26 9450ms 4 107 7799ms Without the System Slot Length the epoch time will be 1 frame casing time without system sit 19 7228ms 107 7
83. ustomization note The contents of Radio B frame 03 and frame 04 may be changed from 00 to 10 which will allow Radio B to listen to all of the transmissions from the Radio D and Radio E Radio C During frame 00 slot 1 00 1 Radios C re transmits what it heard on slot 0 and outputs it to the serial port The frame 01 0 is assigned for the Radio C transmission value 20 in it During the frames 00 2 00 4 Radio C acts as repeater which is indicated by the value of 22 in them So during the slot 2 within the frames 01 04 Radio C will re transmit what it heard on slot 0 or slot 1 within the same frame Customization note The frame 02 and frame 03 contents on Radio C may be changed from 22 to 21 It will not effect the functionality of the system but it will allow the data from Radio B and Radio D to be re transmitted by the Radio C one slot sooner This may or may not have effect on the overall system performance but could be useful in some applications FreeWave Technologies from the frame table consistency standpoint recommends keeping frame 02 and frame 03 contents at 22 Radio D During the frame 00 slot 02 this radio re transmits what it heard on slot 0 or slot 1 within the same frame In other words during the frame 00 Radio D acts as a submaster During the frames 01 and 02 this radio is idle Frame 03 is assigned for its transmission and during the frame 04 slot 01 it re transmits what it heard
84. zero 0 means that there are no submasters in the network and the master will hear and talk to the slaves directly 4 Number of Slave Frames per Master Frame 1 15 This assigns the number of slave frames that occur between a master frame The minimum slave frame is one and the maximum slave frames allowed are fifteen 5 Number of Slave Repeaters per Frame 0 15 This parameter assigns the number of repeaters within a slave frame The maximum number of repeater allowed is fifteen A setting of zero 0 means that there are no repeaters in the network and the master hears the slaves directly 6 Number of Master Frames in Epoch 1 255 This assigns the number of master frames frame castings that occurs within an epoch This number can have a minimum number of one 1 or a maximum number of two hundred and fifty five 255 7 Packet Delimiter Character 0 255 This assigns a delimiter character in hexadecimal that is used to begin all packet transfers to and from the RS 232 port This parameter is only valid in packetized mode It is recommended that an ASCII character be used that is not commonly used It is also suggested to have the same Packet Delimiter character on all of the radios in the system TDMA User Manual TDMA Setup Parameters 8 System Slot Length 8 255 This parameter is commonly used for elongating the frame casing timing for time sensitive applications The default setting of eight 8 is the minimum a

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