ST7580 802.15.4-like MAC layer
Contents
1. 27 7 Revision history 28 ky DoclD025597 Rev 1 3 29 List of figures AN4411 List of figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 4 29 Firmware architecture iii a a haa ae 6 PSIG AIG a A A A ee de er ae eta een ce a ae 8 Fields of the MAC frames e a Gd a add aia a ace N R as 8 EVALKITST7580 1 ai nienean Waka eee eee eens 22 Bootandassociationofanewnode 23 DoclD025597 Rev 1 4 AN4411 Overview 1 Overview The 802 15 4 like communication MAC layer provides services able to build and manage a power line network with a master node referred to as network coordinator and several peer nodes called coordinators Any type of power line network may be created In order to start transmissions a coordinator node needs to join the network it performs an association procedure called active scan The protocol has been created for the STM32 family microcontrollers It assumes a serial communication line UART is used to communicate and exchange data with the ST7580 power line modem device ky DoclD025597 Rev 1 5 29 Firmware architecture AN4411 2 Firmware architecture Figure 1 shows the firmware architecture Figure 1 Firmware architecture STM32 csma ca jas Data Link ST7580 The ST7580 power line modem provides physical layer services together with s2. DoclD025597 Rev 1 ky AN4411 Service description This function checks for a confirm event after a previous scan request The MAC_MImeScanConfirm_t data structure has the following fields s MAC _PanDescriptorList_t PanDescriptorList This structure consists of an unsigned byte PanDescriptorCount which counts how many Beacon frames have been received and an array of MAC_PanDescriptor_t PanDescriptor these have the structure shown in Chapter 4 3 1 e uint8 t ErrorCode Error code of the confirm event it is always set to MAC SAP ERR NO ERROR e uint8 t Status Status of the Scan operation it may have one of the following values MAC SUCCESS successfully completed MAC SCAN IN PROGRESS another Scan sequence was already pending MAC INVALID PARAMETER a wrong Scan value was specified for the scan type and or duration MAC ADD EVENT ERROR unable to transmit the Beacon Request Command frame or any of the error codes returned by the transmission FSM listed in Chapter 4 2 2 e uint8 T ScanType Always set to MAC ACTIVE SCAN Return values e MAC SAP ERR NO ERROR the confirm data was successfully retrieved s MAC SAP ERR PREVIOUS REQUEST no confirm event available 4 3 10 MLME START request uint8 t MAC MlmeStartReq MAC MlmeStartReq L MlmeStartReq With this function a node can set the PAN ID and its role in the network coordinator PAN coordinator The parameters are found in the
3. Cr AN4411 YI o Application note ST7580 802 15 4 like MAC layer By Nunzio Dipaola Introduction The new smart grid systems and the emerging Internet of things concept require advanced web services based on the TCP IPv6 communication protocol The TCP IPv6 stack has been adapted to narrow band communication systems thanks to the work of the 6LowPAN working group of the IETF for narrow band wireless PANs based on the IEEE 802 15 4 compliant MAC layer The same concept can extended to narrow band wired power line communication networks by implementing an 802 15 4 like MAC layer on a 32 bit microcontroller of the STM32 family on top of the ST7580 multi mode power line networking SoC The ST7580 device inside the STarGRID family offers sufficient flexibility to support such protocol and even the STM32F103 MCU has been used for the first firmware release it can be ported to other devices in the STM32 family This document describes the communication protocol and the services provided to the upper layers of the protocol stack June 2014 DoclD025597 Rev 1 1 29 www st com Contents AN4411 Contents 1 A E i aa 5 2 Firmware architecture nanansa 6 3 Framing siria ee ee ee aa 8 4 Service description 11 4 1 Address structure 11 4 2 Data services 12 4 2 1 MC
4. MAC MimestartReq t structure e uint8_tCoordRole This flag controls whether the node is a PAN Coordinator set this field to DEVICE_TYPE_PAN_COORDINATOR or a Coordinator set this field to DEVICE_TYPE_COORDINATOR e uinti6 tPanld The 16 bit PAN identifier Note that although the application may choose this identifier randomly the protocol requires that it is logically and ed with OxFCFF Return value e MAC SAP ERR NO ERROR the request was issued to the MAC 4 3 11 MLME START confirm uint8 L MAC MlmeStartConfirm MAC MlmeStartConfirm_t MlmeStartConfirm When called this function checks for a confirm event relative to a previous start request DoclD025597 Rev 1 19 29 Service description AN4411 4 3 12 4 3 13 20 29 The results are stored into the MAC_MImesStartConfirm_t structure e uint8 t ErrorCode Error code from the confirm retrieval operation it is always set to MAC SAP ERR NO ERROR e Uint8 t Status Status code of the Start operation it may have the values MAC SAP ERR NO ERROR Start sequence completed successfully or MAC INVALID PARAMETER the specified PAN ID is invalid Return values s MAC SAP ERR NO ERROR a valid confirm event is present e MAC SAP ERR PREVIOUS REQUEST no request was previously issued MLME COMM STATUS indication uint8 t MAC MlmeCommStatusIndication MAC MlmeCommStatusIndication t MlmeCommStatusIndication This function checks f
5. MAC internal database PIB PAN Information Base providing the object that the function must read Fields of the MAC_MImeGetReg structure e uint32_t PIBAttribute Integer ID of the attribute to read See Appendix 3 for Attribute list e uint8_t PIBAttributelndex Index used in case of list attribute Return values e MAC SAP ERR NO ERROR the primitive was issued with no errors e MAC SAP QUEUE _ERRFULL unable to issue the event to the FSM The only list attribute managed by the MAC is the neighbor table which contains information about any known node of the network lts ID is MAC_NEIGHBORTABLE_ID 4 3 3 MLME GET confirm uint8_t MAC MlmeGetConfirm MAC MlmeGetConfirm_t MlmeGetConfirm This function checks whether a confirm event has been issued following a previous GET request and returns the attribute value DoclD025597 Rev 1 15 29 Service description AN4411 Note 4 3 4 16 29 Explanation of the MAC_MImeGetConfirm data structure e uint8 T ErrorCode Result of the operation always MAC SAP ERR NO ERROR e uint8 t State State flag of the GET operation it may have one of the following values MAC SUCCESS for a successful read MAC_UNSUPPORTED_ATTRIBUTE when the requested attribute is not found or MAC INVALID INDEX when a list attribute is specified but the wrong index is provided e uint32_t PIBAttribute ID of the attribute e uini8 L PIBAttributelndex Attribute index for a GET operation on a list att
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7. messages up to NEXT_HIGHER_LAYER_MAX_PDU_LENGTH bytes in length through segmentation The default value for NEXT_HIGHER_LAYER_MAX_PDU_LENGTH is 1280 e uint8 t Msdu Pointer to the MSDU e uint8 tMsduHandle The handle associated with the data to transmit e uint8 t TxOptions Special transmission options b0 0tx without ACK 1 tx with ACK b1 0 CAP transmission fixed b2 0 direct transmission fixed e uint8 T SecurityLevel Always zero e uint8 t QoS Requested Quality of Service 1 high 0 normal DoclD025597 Rev 1 ky AN4411 Service description Return values e MAC SAP ERR NO ERROR operation completed successfully e MAC SAP ERR IMPLEMENTATION no spare room in the event queue other operations are already being performed e MAC SAP ERR INVALID ADDR MODE invalid source address mode or destination address mode 4 2 2 MCPS DATA confirm uint8 L MAC McpsDataConfirm MAC McpsDataConfirm t McpsDataConfirm This confirm function checks for the result of the last data transmission request The input object is a pointer to a MAC_Mcps_DataConfirm_t data structure consisting of the following fields e uint8 t ErrorCode Error code of the MCPS DATA confirm operation this field is never used in the current firmware version e uint8 T MsduHandle The handle specified in the MCPS DATA request e uint8 t Status Status of the data transfer operation e uint32 t Timestamp Time at which the
8. 0 MAC_BADCRCCOUNT_ID 4 0 MAC_MAXORPHANTIMER_ID 4 0 MAC_NEIGHBORTABLE_ID 1 N A MAC_PANID_ID R W 2 OxFFFF MAC_NUMBEROFHOPS_ID R 1 0 MAC_FREQNOTCHING_ID R W 1 0 MAC_BSN_ID R 1 0 MAC_DSN_ID R 1 0 MAC_COORDINATORTYPE_ID R W 1 1 MAC_PROMISCUOUS_MODE R W 1 0 MAC_MAXFRAMERETRIES_ID R W 1 3 DoclD025597 Rev 1 25 29 PIB attributes AN4411 Table 5 List of PIB attributes continued 26 29 Identifier R W Length Default value MAC_LASTPACKETLENGTH R W 1 48 MAC_EXTENDEDADDRESS ID pointer R 4 N A DoclD025597 Rev 1 4 AN4411 References 6 References e ST7580 datasheet e UM0932 user manual e STM32F103 datasheet e STM32F103 reference manual e EVALKITST7580 1 data brief e AN4068 ky DocID025597 Rev 1 27 29 Revision history AN4411 7 28 29 Revision history Table 6 Document revision history Date 04 Jun 2014 Revision 4 Initial release Changes DoclD025597 Rev 1 2 AN4411 Please Read Carefully Information in this document is provided solely in connection with ST products STMicroelectronics NV and its subsidiaries ST reserve the right to make changes corrections modifications or improvements to this document and the products and services described herein at any time without notice All ST products are sold pursuant to ST s terms and conditions of sale Purchasers are solely responsible for the c
9. 2_bsp c h 6 29 DoclD025597 Rev 1 ky AN4411 Firmware architecture Table 1 Module details MAC MAC MacConstants h MAC MacEnumeration h MAC MacFrameCreation Handling c h MAC MacFSM c h MAC MacMessageCatalog h MAC MacNeighbourTable c h MAC MacPanDescriptorMng c h MAC MacPibAttributes c h MAC MacPIBTypes h MAC MacSapQueue c h DataLinkLayer channel_access c h DataLinkLayer csmaca c h DataLinkLayer timers c h The source files in DataLinkLayer subfolder are dedicated to the CSMA CA JAS access protocol this can be enabled at build time by declaring a special macro ENABLE_CSMA_CA default If this macro is not declared no access protocol is used MacSapInterface MAC MacSapInterface c h Applications may be built using the API these modules provide DoclD025597 Rev 1 7 29 Framing AN4411 3 8 29 Framing The adopted modulation is an X PSK and the physical frame is the typical PSK frame shown in Figure 2 Figure 2 PSK frame lt i FEE ER A Where e Preamble 32 bit this field is detected as start of frame signal by the receiver e Unique word 32 bit fixed content the receiver evaluates SNR of the medium depending on the perceived quality of this field e Mode 8 bit this field specifies the modulation scheme for the incoming payload in this protocol version it is always set to B PSK s P SDU
10. Length 8 bit length of the P SDU field in bytes e P SDU variable field from 0 up to 248 bytes this is the actual frame payload The P_SDU field contains the MAC PDU with the structure shown in figure 3 Figure 3 Fields of the MAC frame Octets 3 0 2 0 2 18 0 2 0 218 Segment Frame Src Aux Dest Dest rc gt Control Control os PAN PAN SIC security Addr Addr Payload Header Header ID ID Header The content of each field is detailed below Segment control header This field stores useful data for segmentation and reassembly routines Table 2 Table 2 Fields of the segment control header Field Byte Used bits Bit length Details RES 0 7 2 6 Reserved Channel Access Priorit S R 0 1 high 0 normal i LSF 0 0 1 Last Segment Flag 1 yes 0 no SC 1 7 2 6 Segment Count SL 9 8 1 1 0 2 Segment Length SL 7 0 2 7 0 8 Segment Length DoclD025597 Rev 1 ky AN4411 Framing Note that the SL field stores the length of a generic segment in a series not the actual segment Therefore when sending a 140 byte packet while the actual segment size is 60 bytes this field is set to 60 in segment 1 then 60 in segment 2 and 60 again in segment 3 even if this last segment only holds the last 20 bytes Frame control header This field is used for specifying the frame type and the addressing modes table 5 Table 3 Frame control header Field Byte Used b
11. MAC MlmeSetReg t MlmeSetReq DoclD025597 Rev 1 ky AN4411 Service description 4 3 5 4 3 6 This function is called when a SET request must be issued The parameter contains the attribute identifier and its new value The MAC_MlmeSetReq_t data structure fields are e uint32 t PIBAttribute The integer identifier of the attribute to be set See Appendix 3 for Attribute list e uint8 L PIBAttributelndex The index for a list attribute e union PIBAttribute Value This field has one of the following values value8 unsigned 8 bit value value16 unsigned 16 bit value value32 unsigned 32 bit value buffer a generic buffer its length is SAP_MAX_ATTRIBUTEVALUESET_LEN bytes defaulted to 4 e uint8 t PIBAttributeValueLen Length in bytes of the value stored in the PIBAttributeValue field Return values s MAC SAP ERR NO ERROR the request primitive has been successfully issued to the MAC e MAC_SAP_QUEUE_ERRFULL the FSM has no further room for a new SET request event MLME SET confirm uint8 t MAC MlmeSetConfirm MAC MlmeSetConfirm_t MlmeSetConfirm This function checks for a SET confirm event The MAC_MImeSetConfirm_t data structure has the following fields e uint8 t ErrorCode The error code returned from the confirm primitive it is always MAC_SAP_ERR_NO_ERROR e uint8 t State The state of the SET operation lt may have one of the following values MAC_SUCCESS when there are no errors
12. MAC_UNSUPPORTED_ATTRIBUTE when the attribute is not found MAC READ ONLY the requested attribute is read only e uint32_t PIBAttribute The 32 bit identifier of the specified attribute e uint8 t PIBAttributelndex The index for a list attribute Return values MAC SAP ERR NO ERROR the function call returns a valid confirm event e MAC SAP ERR PREVIOUS REQUEST no confirm event was found MLME RESET request uint8_t MAC MlmeResetReq MAC MlmeResetReq_t MlmeResetReq This function requests a reset of the MAC layer The MAC_MlmeResetReq_t data structure has a single field e uint8 t SetDefaultPIB This flag tells the engine whether or not to reset the PIB during the software reset Set it to 1 to reset or 0 to leave it with latest values DoclD025597 Rev 1 17 29 Service description AN4411 4 3 7 4 3 8 4 3 9 18 29 The reset operation always involves a hardware reset of the ST7580 modem The PANDescriptorList and the neighbor table structures are also cleaned Return values e MAC SAP ERR NO ERROR the request was successfully issued e MAC_SAP_ERR_IMPLEMENTATION the Reset FSM was unable to accept a new request MLME RESET confirm uint8 t MAC MlmeResetConfirm MAC MlmeResetConfirm_t MlmeResetConfirm This function checks for a confirm for a previous RESET request primitive The MAC_MImeResetConfirm_t data structure has the following fields e uint8 t ErrorCode Re
13. PS DATA request 12 4 2 2 MCPS DATA confirm 13 4 2 3 MCPS DATA indication 13 4 3 Management services 14 4 3 1 MLME BEACON NOTIFY indication 14 4 3 2 MLME GET request 15 4 3 3 MLME GET confirm ii Ia eee eee 15 4 3 4 MLME SET request 16 4 3 5 MLME SET confirm 17 4 3 6 MLME RESET reguest 17 4 3 7 MLME RESET confirm 18 4 3 8 MLME SCAN request 18 4 3 9 MLME SCAN CON IM ii aa aaa ee eee 18 4 3 10 MLME START request 19 4 3 11 MLME START confirm 19 4 3 12 MLME COMM STATUS indication 20 4 3 13 MLME SYNC LOSS indication 20 5 Application example 22 Appendix A Boot and join sequence 23 Appendix B Modem setup manzunanzunanzuna 24 Appendix C PiBattributes 25 2 29 DoclD025597 Rev 1 ky AN4411 Contents 6 References
14. data transfer has been completed Note this is the device internal time which counts the time in milliseconds following power on Return values e MAC SAP ERR NO ERROR confirm event retrieved successfully e MAC SAP ERR PREVIOUS REQUEST no confirm event retrieved yet The status field may be set to one of the following e MAC SUCCESS operation completed successfully e MAC INVALID ADDRESS both destination and source addresses are missing s MAC INVALID QOS a wrong value for QoS is requested only 0 1 are valid e MAC ADD EVENT ERROR unable to transmit the packet because the transmitting machine is busy e MAC CHANNEL ACCESS FAILURE unable to transmit because the channel is busy e MAC NO ACK Ack when requested is not received 4 2 3 MCPS DATA indication uint8 t MAC McpsDataIndication MAC McpsDataIndication t McpsDataIndication This primitive is issued in case of data reception Ack packets when requested are handled internally by the MAC routines The application level receives confirmation of proper handling when an indication is signaled The indication signaling is also associated with a positive result from any frame corruption reserved fields wrong values check DoclD025597 Rev 1 13 29 Service description AN4411 4 3 4 3 1 14 29 Explanation of MAC_McpsDatalndication_t data structure e uint8 T ErrorCode The error code related to the reception event Always set t
15. eSyncLossIndication_t block is as follows e uint8 t ErrorCode Error code related to the indication event it is always set to MAC_SAP_ERR_NO_ERROR e _uint8_t LossReason e uinti6 tPanid The new discovered PAN identifier Return values s MAC SAP ERR NO ERROR an indication event was successfully retrieved e MAC_SAP_ERR_NOINDICATION_PRESENT no indication event found DoclD025597 Rev 1 21 29 Application example AN4411 5 22 29 Application example The protocol library is delivered with a simple application example running on the EVALKITST7580 1 shown in the following picture Figure 4 EVALKITST7580 1 The application simulates a simple data collection operation from sensor nodes to a data concentrator and a command transmission operation from the data concentrator to the sensor nodes It functions along the following description using at least two kits for communication evaluation Following boot the board starts the active scan procedure for 10 seconds and if no beacon are received because it is alone or it is the first to be powered up it elects itself as PAN coordinator and starts the MAC as PAN coordinator During scan procedure the LEDs DL3 and DL5 blink If a beacon is received because a PAN coordinator already exists the board starts the MAC as a normal coordinator with the retrieved PAN_ID and a random local short address After the associati
16. eives a beacon The fields of the MAC_MImeBeaconNotify_t data structure are set as follows e uint8 T ErrorCode The error code returned by the reception operation e MAC PanDescriptor t PanDescriptor The data structure filled with data from the sender coordinator node DoclD025597 Rev 1 ky AN4411 Service description The return values e MAC_SAP_ERR_NO_ERROR a valid indication was retrieved e MAC SAP ERR NOINDICATION PRESENT no indication event is present The ErrorCode field is always set with value MAC_SAP_ERR_NO_ERROR The MAC_PanDescriptor_t structure has the following fields e MAC DeviceAddress tCoordAddress Address of the sender coordinator e uinti6_tSuperFrameSpec The two byte SuperFrameSpecification received as payload of the beacon e uint8_tGTSPermit Permission for GTS guaranteed time slot Not used in this protocol version it is always zero e uint8_t LinkQuality Signal quality at reception of the beacon that is the SNR detected during decoding e uint32 t Timestamp Arrival time of the beacon e uint8 T SecurityFailure This field signals problems during decryption of the frame Not used in this protocol version always set to MAC_SUCCESS e uint8 T SecurityLevel Cryptographic protection level of the Beacon frame Not used in this protocol version 4 3 2 MLME GET request uint8_t MAC MlmeGetReg MAC MlmeGetRegq_t MlmeGetReq This primitive requests a get read operation on the
17. f the following values MODEM_MOD_BPSK MODEM_MOD_QPSK MODEM_MOD_8PSK MODEM_MOD_BPSK_CODED MODEM_MOD_QPSK_CODED MODEM_MOD_BPSK_CODED_PNA uint8_t channel config Select between single channel reception using either high or low frequency and dual channel reception This can be set to MODEM PHY CONFIG RXMODE DUAL for reception from both channels MODEM_PHY_CONFIG_RXHIGH_PSK or MODEM_PHY_CONFIG_RXLOW_PSK for receiving frames from a high frequency channel or from a low frequency channel DoclD025597 Rev 1 ky AN4411 PIB attributes Appendix C PIB attributes The application is able to read and modify MAC internal attributes in order to change software behavior or access other data Table 5 shows these attributes Table 5 List of PIB attributes Identifier R W Length Default value MAC_ACKWAITDURATION_ID unit is 100 ms R W 1 10 MAC_ASSOCIATEDPANCOORD_ ID R 1 0 MAC_ASSOCIATIONPERMIT_ID R 1 1 MAC_MAXBE_ID R 1 5 MAC_MAXCSMABACKOFFS_ID R 1 8 MAC_MINBE_ID R 1 3 MAC_RESPONSEWAITTIME_ID R 1 30 MAC_SECURITYENABLED_ID R 1 0 MAC_SHORTADDRESS_ID R W 2 OxFFFF MAC_TIMESTAMPSUPP_ID R 1 1 MAC_HIGHPRIORITYWS_ID R 1 0 MAC_TXDATAPACKETCOUNT_ID R W 4 0 MAC_RXDATAPACKETCOUNT_ID R W 4 0 MAC_TXCMDPACKETCOUNT_ID R W 4 0 MAC_RXCMDPACKETCOUNT_ID R W 4 0 MAC_CSMAFAILCOUNT_ID R 4 0 MAC_CSMACOLLCOUNT_ID R 4 0 MAC_BROADCASTCOUNT_ID R W 4 0 MAC_MULTICASTCOUNT_ID R W 4
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19. its Bit length Details Frame type 0 0 2 3 Frame type see notes Security enabled 0 3 1 Always zero Frame pending 0 4 1 Always zero Ack request 0 5 1 Acknowledgment requested PAN ID compression 0 6 1 Enabled disabled see notes Reserved 0 1 7 0 1 3 Dest addr mode 1 2 3 2 Addressing mode see notes Frame version 1 4 5 2 Always zero Source addr mode 1 6 7 2 Addressing mode see notes The frame type field is set to one of the allowed values e 000 Beacon e 001 Data frame e 010 Acknowledgment e 011 MAC Command frame e 100 111 are reserved The PAN ID compression field saves in some cases two bytes when both the source address and the destination address are present and the source PAN ID is identical to the destination PAN ID then this field may be set to one enabled and only the destination PAN ID is copied into the frame source address doesn t have an explicit PAN ID In any other case this field is set to zero The addressing mode fields may be set to one of the allowed values e 00 address field is not present that is no address e 01 is reserved e 10 address field contains PAN ID and a 16 bit short address e 11 address field contains PAN ID and a 64 bit extended address Sequence number This field is under the MAC control It specifies the sequence number of the frame which is useful for matching acknowledgments and distinguishing between subsequent retransmissi
20. node are MLME RESET hardware and software reset of the device modem and MAC MLME SCAN scan of the network nodes if any through the beacon reguest command frame Note that the duration is set by the caller reception of beacon frames sent by other nodes MLME SET setting of the attribute MAC SHORTADDRESS ID also known as the short address of the device and the node activity between the PAN coordinator and coordinator Note that for the node to be a PAN Coordinator the short address must be set to 0 zero MLME START start of the node transmissions In this step the node sets the PAN identifier and sends the identity announcement command frame with its own parameters such as associated PAN short address and extended address DoclD025597 Rev 1 23 29 Modem setup AN4411 Appendix B Modem setup 24 29 The main program can customize the modem configuration in order to set frequencies reception mode modulation scheme and the like void DL LoadStartupConfig DL OBJ T DataLink uint32 L freqH uint32 L freqh uint8 t mod uint8 t channel config This function reads the default settings of the modem copies them into the DataLink data structure and then customizes those values with the new ones provided by the caller They are uint32_t freqH The high reception frequency for the modem uint32_t freqL The low reception frequency for the modem uint8_t mod Modulation scheme selection this can be set to one o
21. o the value MAC_SAP_ERR_NO_ERROR e MAC_DeviceAddress_t SrcAddr The source address e MAC_DeviceAddress_t DstAddr The destination address Note that this address has already been checked so this indication signal means the packet is in the correct desired destination node e uint1i6 T MSDULen Length in bytes of the packet e uint8 t MSDU NEXT HIGHER LAYER MAK PDU LENGTH The actual MSDU uint8 t msduLinkQuality SNR value detected during reception of this packet In case of segmented reception this value derives from the latest received segment e uint8 t DSN Data Sequence Number The sequence number identification of a single transmission e uint32 t TimeStamp Time of completion of the reception operation e uint8 T SecurityLevel Information about security setting cryptography of the frame Not used in the current version of the firmware e uint8 t QoS Requested quality of service set by the sender 0 normal quality 1 high quality Return values MAC SAP ERR NO ERROR the function returned a valid indication event e MAC SAP ERR NOINDICATION PRESENT no indication present that is no packet received at the moment Management services The following services involve the MLME MAC subLayer Management Entity and all the internal MAC management MLME BEACON NOTIFY indication uint8_t MAC MlmeBeaconNotify MAC _MlmeBeaconNotify L MlmeBeaconNotify This primitive is issued when a node rec
22. ome basic data link layer services The role of each block is as follows st7580_wrapper this module works as a wrapper for any access to the modem When transmitting this module sends frames to the modem and manages the local port acknowledgments UART communication When receiving this module analyzes the packet and sends the related event to the right FSM among the MAC machines The outgoing packets are evaluated by the CSMA CA JAS anti collision module in order to obey the medium access protocol rules the only exceptions are ACK packets and all the segments of a series excluding the first MAC this is a set of modules which provides all the functionality of the data link layer Here several FSMs work together to execute requests issued from the higher layer and manage the data gathered by the modem from the power line such as other nodes in the network in a neighbor table the quality level of the medium and internal data structures MacSapInterface this module provides a unique clean interface to the whole set of MAC services including request confirmation and indication primitives This modules is the interface for the application layer which is built upon the power line network device Table 1 shows the source files involved in any block Table 1 Module details Block Modules Notes ST7580_Layenst7580_wrapper c h st7580_wrapper ST7580_Layer st7580_serial20 c h Very low level modules BSP STM32_EVAL st7580_stm3
23. on process finishes the normal coordinator sends dummy messages to the PAN coordinator periodically During normal operation of the coordinator the LED DL5 blinks The PAN coordinator maintains a table of 3 nodes from the MAC neighbor table associated with LEDs DL3 DL4 and DL5 of the board each time it receives a message from one normal coordinator it toggles the associated LED If the TEST 1 button of the PAN coordinator board is pushed a broadcast command message is sent as soon as the coordinator boards receive the command they toggle the LED DL4 For correct operation a main super loop must call the MAC_FSMHandler function to run all the MAC finite state machines and the MODEM_FSM_Management function to run the STM32 ST7580 local communication finite state machine DoclD025597 Rev 1 ky AN4411 Boot and join sequence Appendix A Boot and join sequence Figure 5 shows the boot of a new node and the association procedure This includes the actual scan of the network called active scan Figure 5 Boot and association of a new node Next higher layer MAC MLME RESET request R L MLME RESET confirm MLME SCAN request Beacon Request duration Command frame Active scan reception Le MLME SCAN confirm of Beacon frames MLME SET request short address a La MLME SET confirm MLME START reguest PAN ID l gt Identity Announcement L MLME START confirm Commandiframe The actions performed by the
24. ons A BSN beacon sequence number is used for beacon frames and a DSN data sequence number is used for data frames DoclD025597 Rev 1 9 29 Framing AN4411 10 29 Frame payload This field is used for the MAC payload Different frames are associated with different cases Beacon frame the payload is 16 bits long and can be set to one of the following two values MAC_BEACON_SUPERFRAME_PANCOORD the sender node is a network coordinator and association is allowed MAC_BEACON_SUPERFRAME_COORD the sender node is a coordinator and association is allowed MAC Command frame the command itself is 8 bits long and the payload may vary Two different command frames are available MAC_BEACON_REQ_ID Beacon Request Command Frame only the command code is specified no payload MAC IDENTITY ANNOUNCEMENT Identity Announcement Command Frame the command code is followed by the 16 bit short address and then by the 64 bit extended address of the node Acknowledgment no payload Data frame any payload Frame check sequence Not used The physical layer of the ST7580 provides hardware error detection so this field is not filled with any data DoclD025597 Rev 1 ky AN4411 Service description 4 4 1 Service description The firmware offers a complete set of service primitives as listed in Table 4 Table 4 List of service primitives reque
25. or a communication status indication event from the MAC that is a detailed report about the last communication event The MAC_MImeCommsStatusIndication_t data structure has the following fields e uint8 t ErrorCode The error code of the confirm event check it is always set to MAC_SAP_ERR_NO_ERROR e uinti6 tPanid This is the PAN identifier of the source node e MAC_DeviceAddress_t SrcAddr e MAC_DeviceAddress_t DstAddr The addresses of both source and destination nodes e uint8 t Status Last result of the communication channel May be one of the following values MAC_COUNTER_ERROR problem during reassembly process due to wrong segment received MAC_NO_ACK after transmission an ack was expected but never received MAC_CHANNEL_ACCESS_FAILURE the medium was detected as busy too many times transmission aborted e _uint8_t SecurityLevel Code related to cryptography of the message Not used in this version of the software Return values s MAC SAP ERR NO ERROR an indication event was successfully retrieved e MAC_SAP_ERR_NOINDICATION_PRESENT no indication was found MLME SYNC LOSS indication uint8_t MAC MlmeSyncLossIndication MAC _MlmeSyncLossIndication_t MlmeSyncLossIndication DoclD025597 Rev 1 ky AN4411 Service description This primitive is issued to the next layer above when an overlapping PAN is detected this case is called PAN ID conflict The structure of the MAC_MIm
26. ribute e uint8_tPIBAttributeValue sSAP_MAX_ATTRIBUTEVALUEGET_LEN The value retrieved by the GET operation The buffer is SAP_MAX_ATTRIBUTEVALUEGET_LEN bytes long default 20 although 13 are used at most e uint8_t PIBAttributeValueLen Length in bytes of the attribute Return values e MAC SAP ERR NO ERROR a valid confirm event was copied into the MAC_MImeGetContfirm data structure e MAC SAP ERR PREVIOUS REQUEST no confirm event was found The PIBAttribute Value buffer has different contents depending on the actual attribute For a read from the Neighbor Table it is structured as a small set of integer values related to a specified node in the following sequence e 2 bytes for the actual PAN ID e 2 bytes for the actual short address optional e 8 bytes for the extended address optional e 1 byte for the age of the entry in minutes This structure is therefore 5 bytes long when only the short address is present or 11 bytes long when only the extended address is present or 13 bytes long when both short and extended address are present In order to distinguish between these cases refer to the PIBAttributeValueLen value beforehand For integer values the structure is simpler 1 2 4 bytes When reading the extended address of the current node the PIBAttributeValue is set with a pointer 32 bit value to an 8 byte buffer with the long address MLME SET request uint8_t MAC MlmeSetReq
27. st confirm indication MCPS DATA yes yes yes MLME BEACON NOTIFY yes MLME GET yes yes MLME SET yes yes MLME RESET yes yes MLME SCAN yes yes MLME START yes yes MLME COMM STATUS yes MLME SYNC LOSS yes Address structure The address of a node is a commonly used data structure so it is useful to acquire it beforehand typedef struct uint8_t Mode uint16_t PanID union uint16_t Short uint8 t Extended MAC_ADDR64 SIZE MAC DeviceAddress t DoclD025597 Rev 1 11 29 Service description AN4411 4 2 4 2 1 12 29 where e uint8 t Mode is the address mode see notes below table 5 e uinti6 tPaniD is the 16 bit PAN Identifier e uinti6 T Short is the 16 bit short address e uint8 T Extended is the 64 bit extended address the macro MAC ADDR64 SIZE has value 8 Data services The data services include all the primitives related to data transmission that is to MCPS DATA functions such as request confirm and indication MCPS DATA request uint8_t MAC McpsDataReq MAC McpsDataReq_t McpsDataReq This function is called when a data transmission is requested Input data is a reference toa MAC_McpsDataReq_t data structure with the following fields e uint8 t SrcAddrMode The source address mode as listed in the notes below table 5 e MAC _DeviceAddress tDstAddr The destination address e uinti6_t MsduLength The length in bytes of the MSDU The firmware can handle
28. sult of the confirm event it is always setto MAC SAP ERR NO ERROR e uint8 t Status Status of the reset operation it always has the value MAC SUCCESS Return values s MAC SAP ERR NO ERROR the confirm event was retrieved successfully e MAC SAP ERR PREVIOUS REQUEST no confirm event MLME SCAN request uint8_t MAC MlmeScanReq MAC_MlmeScanReq_t MlmeScanReq When anode starts up the next layer above MAC calls the active scan procedure in order to check the actual network status This function issues the necessary primitive and other nodes if any send their beacons See Appendix A for the complete description of the join procedure The parameters in the MAC MimeScanReq tare e uint8 T ScanType Select the scan type Only Active Scan is allowed set this to the value MAC ACTIVE SCAN e uint32 t ScanChannels Used for selecting channels to check during the scan operation Not used in this protocol version e uint8 TL ScanDuration Duration in seconds for the whole scan operation max is 60 a zero setting is not allowed e uint8 T ChannelPage e uint8 T SecurityLevel These parameters are not used in this version of the software Return values s MAC SAP ERR NO ERROR the request event was successfully issued to the Scan FSM s MAC SAP ERR IMPLEMENTATION unable to send the request to the scan FSM MLME SCAN confirm uint8_t MAC MlmeScanConfirm MAC_MlmeScanConfirm_t MlmeScanConfirm
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