PowerNut User`s Manual
Contents
1. PowerNut User s Manual PowerNut User s Manual JK microsystems Unless otherwise noted this document and the information herein disclosed are proprietary to JK microsystems Inc Any person or entity to whom this document is furnished or having possession thereof by acceptance assumes custody thereof and agrees that the document is given in confidence and will not be copied or reproduced in whole or in part to meet the purposes for which it was delivered The information in this document is subject to change without notice and should not be construed as a commitment by JK microsystems Inc JK microsystems Inc will make every effort to inform users of substantive errors JK microsystems Inc disclaims all liability for any loss or damage resulting from the use of this manual or any software described herein including without limitation contingent special or incidental liability JK microsystems Inc recognizes our customer s need for a consistent product and will make every effort to provide one In order to provide the best possible product for all of our customers we reserve the right to make incremental improvements 1n our product designs Flashlite 1s a trademark of JK microsystems Inc MS DOS is a registered trademark of Microsoft Corporation XDOS 1s a copyright of HBS Corporation All other brand and product names are trademarks or registered trademarks of their respective companies PowerNut User s Manual Ver2. switched raw on J3 6 If the application does not require the 5 volt switching regulator to be active JP3 pins 1 and 3 should be unconnected so the 5 volt switching regulator consumes no power To save the jumper for future use the physical jumper may be placed on JP3 pins 3 and 5 JP3 5 is not connected to anything 12 Hardware PowerNut User s Manual JK microsystems The PowerNut has the capability to sense low voltage conditions A low voltage condition occurs when the switched version of the input voltage 1s lower than a user programmable threshold The figure below shows the relevant circuit features PIC16LC710 Ain TO OTHER DOWNSTREAM COMPONENTS The voltage divider composed of R2 and R4 is placed after the downstream control switch Q2 Q3 This means that a low voltage test may only occur when Q2 amp Q3 are closed This was done to save power when downstream devices are de energized C4 is a filter and enhances the PowerNut s ability to take consistent measurements on a noisy power rail The ADC has an 8 bit resolution and uses the PIC s 3 3 volt power rail as a reference U1 is National Semiconductor s LP2951ACM 3 3 micropower regulator and 1s used to generate the PIC s 3 3 volt rail and ADC reference voltage The LP2951ACM 3 3 has approximately a 1 error in its output voltage over temperature Another source of error and the dominate one is the voltage drop across the D1 and MOSFETs Q2
3. DATA 15 and the parity bit then we will have an even number of bits Note that the start bit is excluded from this computation T2 marks the time when the PowerNut receives the first bit of the 3 bit command The command is transmitted on the clocked serial interface least significant bit LSB first T3 and T4 indicate when the next two bits of the command are accepted Note that the bit clocked in at T4 is the command s most significant bit MSB T5 indicates the start of the operand Like the command the 16 bit operand appears on the bus LSB first T20 marks the sampling of the operand s MSB 20 Communications Protocol PowerNut User s Manual JK microsystems At T21 the master controller releases the DATA IO signal and causes the CLK signal to go low The DATA IO signal is now a high impedance signal that the PowerNut can drive At T22 the master causes the clock line to assert once again Upon seeing this the PowerNut will shortly there after time T23 drive an ACK NACK onto the bus An ACK HIGH level indicates that the correct number of bits were received and that the parity bit was correct Shortly after the master de asserts the CLK at time T24 the PowerNut will stop driving the DATA line time T25 The time between T22 and T23 is 5 ms maximum The maximum time between T24 and T25 is also Sms maximum The master controller should sample DATA IO for ACK NACK Just before driving CLK low for the final ti
4. NUTCOMM SLEEP A sleep for 10 seconds NUTCOMM SLEEP 0 wake up NUTCOMM LPTEST 0000 perform a low battery test 26 Software PowerNut User s Manual JK microsystems NUTCOMM will allow a Flashlite 186 to operate a PowerNut from the command line or batch files However NUTCOMM does expect that the Flashlite 186 be connected to the PowerNut in a prescribed manner If you have a different controller or wish to simply use different IO pins you can modify NUTCOMM to suit your requirements All of the hardware specific subroutines for NUTCOMM can be found in 186 IO ASM Simply by modifying this file you will be able to change which port pins are used for CLK and DATA JK microsystems used MASM Microsoft Macro Assembler 5 0 to build NUTCOMM COM However any x86 assembler should be able to handle the code in NUTCOMM ASM and 186 IO ASM WAKIOSEC WAK10SEC COM is will send a shutdown for 10 seconds command to the PowerNut WAKI10SEC does expect that the Flashlite 186 be connected to the PowerNut in a prescibed manner If you have a different controller or wish to use different IO pins or wish to modify the command sent you can modify the WAK10SEC source code to suit your requirments All of the hardware specific subroutines for WAKIOSEC can be found in 186 IO ASM Simply by modifying this file you will be able to change which port pins are used for CLK and DATA JK microsystems used MASM Microsoft Macro Assembler 5 0 to bui
5. board will have no reverse polarity protection With D1 shorted it will not contribute a voltage drop between the input power connector and the downstream connector JK microsystems recommends leaving JP1 open during development thus retaining the reverse polarity protection During production JP1 can be installed in applications where squeezing millivolts from a battery is more important than the reverse polarity protection offered by D1 JP2 is a two pin jumper It 1s not used in the current version of the PowerNut JP3 contains the Downstream Configuration Jumpers JP3 Downstream Voltage Configuration Jumpers Regulated 5 Volts Raw Input Voltage Factory Default 3 5 2 6 J1 is the Power Input Connector J1 is a two position 5 MM screw terminal and is capable of accepting solid or tinned wire from 14 AWG to 24 AWG J1 Power Input Connector Name j V4 POWER 5 to 30 volts 7 to 30 if on board 5 volt regulator is used POWER Current Return GROUND Hardware 15 JK microsystems PowerNut User s Manual J2 is the Downstream Voltage Connector J6 is a two position 5 MM screw terminal and is capable of accepting wire size from 14 AWG to 24 AWG J2 Downstream Voltage Connector Name POWER Caren Retur GROUND POWER _ Downstream Voltage as set by JP3 jumpers J3 is the PowerNut s Digital interface J3 Logic Connector If enabled this pin will go HIGH to indicate 2 LOWBAT OUTPUT that the input
6. board programmable low voltage detection and reporting Simple to use clocked serial interface On board heartbeat LED with programmable enable Easy to use screw terminals for input and downstream power Compact 2 x 3 footprint On board programmable timer allows automatic wake up of downstream devices Use of parity and ACK NACK ensures reliable message exchange PowerNut consumes 180uA max 58 100uA typical when downstream devices are off Overview l JK microsystems PowerNut User s Manual Operation When power 1s first applied to the PowerNut s power in connector J1 the PowerNut energizes the downstream connector J2 This will supply power to downstream devices The downstream voltage may be selected to be 5 volts generated by the PowerNut s on board 5 volt regulator or to be approximately equivalent to the raw input voltage Warning If you plan to use the PowerNut to supply voltage to a device that requires a regulated 5 volt supply then you must set the jumpers on JP3 before applying power If the jumpers on JP3 are configured incorrectly then the 0 downstream device will be provided with a voltage higher than five volts This WILL CAUSE DAMAGE to a 5 volt only device Commands are sent to the PowerNut over the clocked serial port The PowerNut ignores commands sent within one second of a PIC reset such as occurs when input power 1s first applied to J1 The PowerNut also ignores commands sent within one
7. controller sends a SHUTDOWN command to the PowerNut The command takes approximately half a second to communicate After the command is received the PowerNut de energizes the downstream devices and imposes a one second communications blackout At T SLEEP plus 1 5 seconds the PowerNut will accept commands again When the downstream connector is de energized the only command that will be executed is the SHUTDOWN for ZERO seconds command Other commands maybe sent while the downstream devices are de energized and the PowerNut will provide an ACK indicating that the command was received but all commands will be ignored except a SHUTDOWN for ZERO seconds command The figure shows that at the appointed wake up time T_WAKE the PowerNut energizes the downstream connector This is followed by a one second communications blackout One second after T WAKE the PowerNut will accept further commands 18 Communications Protocol PowerNut User s Manual JK microsystems After the receipt of a message the PowerNut will be unable to receive another message for a maximum of one second This means that for reliable communications the master should send commands spaced at least one second apart Most commands are processed in much less than a second but a one second spacing of commands ensures reliable operation If the target system drives DATA IN and listens to DATA IO then the target system doesn t have to worry about releasing DATA I
8. executables and source files are available for all the utilities at www jkmicro com The files are also available on the PowerNut Development CD All other JK microsystems Development CDs contain these files in the JKmicro Accessories PowerNut directory NUTCOMM JK microsystems provides a utility for the Flashlite 186 This utility 1s called NUTCOMM COM The full source code is also available NUTCOMM ASM also required is 186 IO asm This utility was written in assembly language so that the executable s footprint would be as small as possible Just typing NUTCOMM COM at the command prompt will generate a few lines of text explaining how to use this utility The usage is NUTCOMM lt command gt lt param gt Both the command and param field are case insensitive NUTCOMM COM accepts sleep config and Iptest as commands These correspond to the PowerNut s shutdown set configuration word and Perform Low Battery Test commands The lt param gt field is the 16 bit operand to be sent with the command This field is interpreted as hexadecimal This field is at most four digits and contains no 0x prefix or h suffix There is no need to add leading numeric digits to alpha characters that are part of the hexadecimal number All of the following are valid parameters 0 00 000 0000 a Oa 000a FED OFED The following are not valid 0x0000 OAh OFFFF Examples of commands are
9. second of turning off or on the downstream voltage This ensures the power is stable on downstream devices before commands are accepted by the PowerNut This is a technique that rejects the noise that occurs on the clocked serial interface when a downstream device 1s making a power transition and attempting to drive the serial interface If a command is sent while the PowerNut is not accepting commands the PowerNut will not acknowledge the transaction and the controller sending the command hereby referred to as the master controller or the master will need to send the command again Getting Started To begin development you will need the following The PowerNut Power supply between 7 volts and 30 volts capable of delivering 300 mA A load that will provide an indication when power is applied A voltmeter A controller capable of sending clocked serial messages Cables to connect the controller to the PowerNut If you have a JK microsystem s PowerNut Development Kit you will find an LED that can be used for a load This LED has an internal current limiting resistor The Anode positive leg will be marked with red heatshrink You will also find wires pins and connector shells that will allow you to connect the PowerNut to any of JK Microsystems controllers To crimp the wires into the pins you will have to supply a suitable crimp tool 2 Operation PowerNut User s Manual JK microsystems This example assumes you wil
10. the measured voltage is less than the threshold voltage in the configuration register then the Low Power LED 1s lit if enabled and the Low Power Signal J3 2 is driven HIGH if enabled Both the Low Power LED and the Low Power Signal J3 2 can be enabled or disabled by bits in the configuration register 24 Communications Protocol PowerNut User s Manual JK microsystems Guidelines for Reliability To ensure reliable operation of the PowerNut JK microsystems offers these guidelines i A bit time of 50 ms seems to offer excellent reliability and should be easily generated by any controller DATA IO or DATA IN should make its transition as close to falling edges of CLK as possible CLK s duty cycle should be as close to 50 as possible DATA IO or DATA IN line has a minimum setup time of 5 ms before the rising edge of CLK DATA IO or DATA IN line has a minimum hold time of 10 ms after the rising edge of CLK Wait two seconds after power is first applied to the PowerNut before sending commands This will give the PowerNut s on board processor time to reset and initialize Ifthe low battery test is going to be used and the Low Voltage Signal J3 2 is connected to the device receiving power from the downstream connector you MUST disable the Low Voltage Signal before de energizing the downstream connector Failure to do this will result in a condition called bleed through whereby the device that
11. voltage is lower than the programmed low voltage threshold DATA IO Data signal for the clocked serial mterface INPUT Clock signal for the clocked serial interface DATA IN INPUT Optional data mput signal SWITCHED POWER Switched output that can be used to drive RAW downstream devices 16 Hardware PowerNut User s Manual JK microsystems Communications Protocol The PowerNut uses a clocked serial interface to receive commands This interface consists of a CLK input and a bidirectional DATA IO signal and an optional DATA IN signal Target systems may be developed to use the single bidirectional DATA IO signal or to use DATA IN as a dedicated input and DATA IO as a dedicated output The controller issuing commands to the PowerNut is considered the master and is responsible for generating the CLK signal Messages to the PowerNut consist of a start bit an even parity bit 3 bit command and 16 bit operand Following a message the master generates one additional CLK pulse and the PowerNut drives the DATA IO line high or low to indicate an acknowledge ACK or error NACK The CLK pulses must be between 22 milliseconds and 80 milliseconds in duration and as close to a 50 duty cycle as possible This implies that the minimum time for a message to be transmitted is about half a second 1 start bit 1 parity bit 3 bit command 16 bit operand ACK 22 x 22 ms 484 ms Some controllers have large ride through capacit
12. will startup again note the BIOS post on the PC terminal program and lit LED Next we consider how to have an application on the Flashlite 186 run periodically 8 Getting Started PowerNut User s Manual JK microsystems Pertodically Running an Application The simplest method of running an application periodically is to place a call to the application in the STARTUP BAT file on the controller followed by a call to a program that will send a command to the PowerNut to shutdown and subsequently wake the controller To illustrate this technique we will need a sample application On the JK microsystems Development CD in the PowerNut sub directory there is a sample application called SAMPAPP COM This is also available at www jkmicro com Upload SAMPAPP COM to the Flashlite 186 Execute SAMPAPP COM on the Flashlite 186 Some text indicating that the sample application ran and then terminated will be displayed To run SAMPAPP COM periodically we will place a call to SAMPAPP COM in the STARTUP BAT file on the Flashlite 186 followed by a call to WAK10SEC COM Using whatever technique you favor create a STARTUP BAT file on the Flashlite 186 s B drive that looks like PROMPT P G PATH A B B BIN SAMPAPP COM WAK10SEC COM A workable technique for creating this file is to use NOTEPAD on the host computer to create the file then use UP COM to bring it over to the Flashlite 186 With the new STARTUP BAT file in place the syste
13. O for the PowerNut to be able to drive it for the ACK NACK phase Such a target system only has to read the ACK or NACK on DATA IO at the appropriate time In such a system DATA IO will be driven HIGH by driving DATA IN HIGH DATA IO will be pulled LOW by driving DATA IN low For the remainder of this document we will speak of driving DATA IO to a state The reader must bear in mind that this can be do by either driving DATA IO directly or by driving DATA IN The master initiates all communications with the PowerNut The master is responsible for generating the CLK The PowerNut looks for a rising edge on CLK and a LOW value on DATA _IO to mark the start of a transmission The PowerNut clocks in DATA IO on subsequent rising edges or CLK On the 23 rising edge of CLK the PowerNut turns around DATA IO and drives an ACK or NACK On the next falling edge on CLK the 23 falling edge the PowerNut release DATA IO Communications Protocol 19 JK microsystems PowerNut User s Manual The figure below shows the sequence required for each transaction T23 T25 mo Ti 122 mue ig I PULP DATA START PARITY X CMDO X CMD1 X CMD2 X DATAO X DATA1 e DATA15 TO marks the start of the transaction DATA_IO is driven low indicating a start bit T1 marks when the PowerNut samples the parity bit The PowerNut expects to see an EVEN parity bit This means that if we count all of the 1 s in the command CMD0 CMD2 and operand DATAO
14. T 1 0x43 VALUE 10 volts 22 Communications Protocol PowerNut User s Manual JK microsystems BITs 7 0 The eight bit Low Voltage Threshold is a binary code corresponding the PowerNut s analog to digital converter s codes The following codes are typical Binary Code Low Voltage Threshold volts 0x35 8 0 0x43 10 0 0x99 22 0 Bit7 is the most significant bit while Bit0 is the least significant The default value of the low voltage threshold is set to 0x43 which translates to approximately 10 volts BIT 8 Setting this bit enables the Low Voltage signal J3 2 The default value of this bit 1s ZERO If this bit is ZERO then J3 2 will never be driven high regardless of the low battery condition It is good practice to disable this bit before de energizing the downstream connector to prevent bleed through Bleed through is a condition in which a downstream device is de energized but still bleeds power through a signal pin This condition 1s also referred to as a device being parasitically powered or being powered through a sneak path This is an undesirable condition and should be avoided See the Guidelines for Reliability section of this manual BIT 9 Setting this bit enables the Low Voltage LED The default value of this bit is ONE If this bit is set to a ONE the Low Voltage LED will light if the results of the next low voltage test indicate the measured voltage is below the Low Voltage Threshold If the LED 1s in a non visible loc
15. T OUTPUT that the input voltage is lower than the programmed low voltage threshold DATA IO Data signal for the clocked serial mterface INPUT Clock signal for the clocked serial mterface DATA IN INPUT Optional data input signal SWITCHED POWER Switched output that can be used to drive RAW downstream devices Now that you can identify the major PowerNut components by name and function let s proceed with putting together the first getting started system 4 Getting Started PowerNut User s Manual JK microsystems Turning on the PowerNut The first order of business 1s to configure the PowerNut s downstream connector voltage to supply suitable voltage for the target system Jumpers on JP3 will need to be configured The factory default settings for JP3 are for 5 volt downstream operation For our system we need to configure the downstream voltage to be approximately the same as the input voltage Configure the jumper blocks on JP3 so the pins 3 and 5 are shorted and pins 2 and 6 are shorted Second attach a load to the downstream connector A digital volt meter DVM or digital multimeter DMM is a suitable load An LED with current limiting resistor is also a suitable load If you have the PowerNut development kit you will find an LED with an internal current limiting resistor The anode positive leg has red heatshrink on it Third apply power to PowerNut The PowerNut s downstream connector will become e
16. act Information JK microsystems Inc 1403 Fifth Street Suite D Davis CA 95616 Telephone 530 297 6073 Fax 530 297 6074 Email sales jkmicro com sales inquiries support jkmicro com technical support Web http www jkmicro com Rev Date Author Changes Daa aaa ae Contact and Revision Information JK microsystems 29
17. amp Q3 This will depend on both the input voltage and the current drawn through D1 and the MOSFETs As part of your system development you should measure the difference in voltage between the input voltage on J1 and the switched voltage on J3 6 This will allow you to select a low voltage threshold suitable for your application Some experimentation will likely be required Hardware 13 JK microsystems PowerNut User s Manual If the voltage drop across reverse polarity protection diode D1 is problematic the D1 may be defeated by installing a slip on jumper on JP1 or an SMT jumper in R1 The following figure shows relevant circuit details Optional ZERO OHM 0805 SMT resistor 0 100 slip on jumper To remaining PowerNut electronics If D1 1s defeated it 1s possible to damage the PowerNut by applying input power of the wrong polarity JK microsystems recommends defeating D1 only in systems where the drop across D1 can not be tolerated and then only in production systems 0 While doing system development it 1s prudent to maintain the reverse polarity protection D1 provides Defeating D1 will affect your low voltage threshold settings for the low battery test Additional experimentation may be required during development to accommodate the change 14 Hardware PowerNut User s Manual JK microsystems Jumpers and Connectors JP1 is a two pin jumper If this jumper is installed shorted then D1 is defeated and the
18. ation this bit can be cleared to a ZERO and then the Low Voltage LED will not light under any circumstances This will save power It may be desirable to clear this bit before putting down stream devices to sleep BIT 10 Setting this bit enables the Heartbeat LED Default Value is ONE If this bit is set the heartbeat LED will flash once every four seconds when the PowerNut has de energized its output connector If a human is present this provides a visual indication that the PowerNut is operating properly Ifa human is not available under normal operating conditions then the Heartbeat LED may be disabled to save battery power BIT 11 15 These bits are reserved for future use Communications Protocol 23 JK microsystems PowerNut User s Manual Perform Low Battery Test CMD 101 0x05 OPERAND 0x0000 To OxFFFF This command initiates a low battery test The operand is ignored A low battery test may only be performed when the downstream connector is energized If this command is received while the downstream power connector is de energized then this command will be ignored A low battery test compares the voltage after the main switch MOSFETs Q2 amp Q3 see the Hardware section of this manual to the low voltage threshold in the lower 8 bits of the PowerNut s configuration register If the measured value is equal to or greater than the threshold voltage set in the configuration register then no action 1s taken If
19. downstream device we will move on to a system in which the master controller receives power from the PowerNut Getting Started 7 JK microsystems PowerNut User s Manual Powering a Downstream Controller Turn off power to the test system Rewire the system as shown in the figure below Flashlite 186 Downstream Voltage Indicator JK microsystems and Load Power Supply 7 30 volts user supplied As before the figure does not show the serial connection between the host PC and the Flashlite 186 Apply power to the system The PowerNut will turn on downstream power to the Flashlite 186 You can verify this both by observing the downstream load indicator LED 1s lit and by noting the BIOS post on the host PC s terminal program In the first test system you used UP COM to put the PowerNut application WAK10SEC COM on the Flashlite 186 Therefore WAK10SEC COM should be still be available on the Flashlite 186 If for some reason you removed WAK10SEC COM or skipped the last example load WAKIOSEC COM from the JK microsystems Development CD onto the Flashlite 186 This code is also available at www jkmicro com Next execute WAK10SEC COM on the Flashlite 186 The PowerNut will receive the command to turn off downstream power for 10 seconds The PowerNut will then do so The LED will go dark and the Flashlite 186 will be tuned off After 10 seconds the PowerNut will turn on power to the downstream connector and the Flashlite 186
20. how to set this serial communication up with a host PC refer to your Flashlite 186 User s Manual On the JK microsystems Development CD you will find an application called WAKIOSEC COM If you do not have a Development CD or can not find the program you may download the program from www jkmicro com 6 Getting Started PowerNut User s Manual JK microsystems Use UP COM on the Flashlite 186 and install WAK10SEC COM on the Flashlite 186 s B drive WAK10SEC COM will use the Flashlite 186 s PIO 31 J9 5 as a CLK for the PowerNut and PIO 1 J9 10 as the DATA IO line The astute engineer will note that the Flashlite 186 s documentation shows J9 5 as INT2 No need to be alarmed The Flashlite 186 multiplex s a number of functions on this single pin and WAK10SEC COM configures J9 5 as a general purpose I O port PIO bit 31 WAK10SEC COM will send a command to the PowerNut to turn off the downstream power for 10 seconds When the power is first applied to the system you should see a BIOS post from the Flashlite 186 on the host PC You should also see the load LED lighted Run WAK10SEC COM The load LED should turn off for 10 seconds then turn back on You should also see the PowerNut s heartbeat LED blink briefly every four seconds Using a DMM measure the voltage across the load and verify that 1t 1s suitable to power the Flashlite 186 7 30 volts Now that we have confirmed the PowerNut s ability to shutdown and wake up a
21. is supposed to be shut off draws excessive current from the I O pin connected to J3 2 This will result in wasted power This may result in the downstream device not turning off completely This may result in the downstream device not resetting correctly on power up In some very rare cases it may result in damage to the PowerNut and or to the downstream device ALWAYS disable the Low Voltage Signal before de energizing the downstream connector if J3 2 is connected to a device that is downstream of the PowerNut 8 Allow one second between messages 9 10 The PowerNut ignores messages for one second after turning on or off downstream power Avoid sending messages during this time Check the ACK NACK on each message If the master does not receive an ACK then wait TWO seconds and send the message again This will avoid the condition in which the master requests that power be turned off and then does not check the ACK and enters a loop of some kind but the message was garbled and the PowerNut ignored it thus not shutting down power This condition can be very difficult to recover from unless there is a watchdog on the master Guidelines for Reliability 25 JK microsystems PowerNut User s Manual Software Software running on a master controller directs the PowerNut s behavior This section describes software that 1s available from JK microsystems This section also discusses briefly how to modify the available software All
22. itializing O a In the above example the Flashlite 186 must run for at least a second before executing the call to WAKIOSEC COM Otherwise the PowerNut will reject the command to shutdown as noise associated with the Flashlite 186 powering up The combination of boot code and SAMPAPP COM provide the requisite one second delay Hardware General Theory of Operation The heart of the PowerNut is a PIC16LC710 from Microchip Technology This is a complete microcontroller in an 18 pin SOIC package The PowerNut runs the PIC16LC710 at 32768 Hz The PIC16LC710 monitors the CLK and DATA DATA IN and DATA IO signals for commands Each transmission is checked for validity by looking at the parity bit and verifying the correct number of clock cycles occurred during the transmission If the message is deemed valid then during the last clock period of the communication the PowerNut will turn around the DATA IO signal and drive an ACK high voltage on to the DATA line Users that want to use a bidirectional signal for DATA can simply use DATA IO This was used in the getting started examples Users that want to use separate signals for data in and data out can use DATA IN as PowerNut s data input and DATA IO as PowerNut s data output A quick glance at the figure on the facing page shows that DATA IN is ORed with DATA IO through a diode The pull down resistor ensures DATA IO is held at a logic zero LOW voltage when DATA IN i
23. l be using is a JK microsystems Flashlite 186 If you have another controller you will still be able to follow this example although when it comes time to hook up your controller to the PowerNut s digital interface you will have to work out the details specific to your system In addition the software provide with the PowerNut is intended to run on JK microsystems controllers If you will not be using a JK microsystems controller for your project then you will have to write code for your specific controller to talk to the PowerNut over the clocked serial interface Getting Oriented In preparation for setting up our Getting Started test system let s examine the PowerNut layout and important features The following figure shows the location of major components C2 C8 Em EZ a R20 A e a C9 U3 pee fa HEARTBEAT DS1 E E LOW VOLTAGE L1 D3 D1 Reverse Polarity Protection Diode Q2 and Q3 MOSFETs used to switch power U2 PIC16LC710 DS1 Low Battery LED DS2 Heartbeat LED Getting Started 3 JK microsystems PowerNut User s Manual JP1 Disable Protection Diode Jumper JP2 not used JP3 Downstream Voltage Configuration Jumpers JP3 Downstream Voltage Configuration Jumpers Regulated 5 Volts Raw Input Voltage Factory Default 1 3 3 5 2 4 2 6 J1 Power Input Connector J2 Downstream Voltage Connector J3 Logic signals J3 Logic Connector If enabled this pin will go HIGH to indicate 2 LOWBA
24. ld WAK10SEC COM However any x86 assembler should be able to handle the code in WAK10SEC ASM and 186 IO ASM CNUT Is a utility that allows a controller to send commands to a PowerNut This utility 1s functionally equivalent to the NUTCOMM utility CNUT was written entirely in C The drawback of this is that the footprint of the executable is larger than that of NUTCOMM COM The hand coded assembly of NUTCOMM generates about a 2 3K byte executable and CNUT EXE 1s 38K bytes However some users may find modifying a C program or porting 1t to another platform easier than manipulating the NUTCOMM assembly source code Software 97 JK microsystems PowerNut User s Manual Specifications Supply Voltage Current Consumption with no load attached Operating Temperature Humidity Physical dimensions mounting holes Mechanical Drawing 5 30 VDC if not using the on board 5 volt switching regulator 7 30 VDC otherwise Downstream shutoff 180uA max 58 to LOO UA typical Downstream active on board 5V disabled Vin 5V 3 3mA Downstream active on board 5V disabled Vin 30V 7 5mA Downstream active on board 5V active Vin 7V 11mA Downstream active on board 5V active Vin 30V 15mA 20 to 85 C 5 90 non condensing 2 x 3 x 0 6 6 hardware 4 places m m m m m m ma m m m m m m E CRO COM F HEARTBEAT fia LOW VOLTAGE L1 i 28 Specifications PowerNut User s Manual Cont
25. m will run SAMPAPP COM approximately every ten seconds On boot the Flashlite 186 will execute AUTOEXEC BAT from it s A drive The last statement in AUTOEXEC BAT calls STARTUP BAT This file will execute the SAMPAPP COM followed by WAK10SEC COM This will cause the PowerNut to shut off the Flashlite 186 for 10 seconds then turn it back on thus starting the process over again To begin the process simply reset the Flashlite 186 by removing and reapplying power to the system Alternatively you can just type boot at the command prompt no quotes If everything is functioning properly you should observe the messages from SAMPAPP COM appearing on the host PC about every ten seconds Getting Started 9 JK microsystems PowerNut User s Manual There 1s a small fixed time that 1s required for the Flashlite 186 to boot about 400 ms and for the PowerNut to receive commands from the Flashlite about 500 ms This overhead will make the actual period deviate from 10 seconds somewhat The overhead of booting and communicating is less significant for longer sleep periods In applications that require precise timing the system developer can adjust the sleep time through experimentation NOTE The PowerNut does not accept commands for one second after the downstream connector is energized This is to eliminate the possibility of receiving erroneous commands due to noise on the clocked serial interface while the downstream controller is in
26. me T24 Communications Protocol 21 JK microsystems PowerNut User s Manual Commands and Capabilities The PowerNut has several different commands This section discusses each command in detail Shutdown CMD 001 0x01 OPERAND 0x0000 To OxFFFF This command will cause the PowerNut to de energize the output connector and wait the number of seconds specified in the operand before energizing the output connector again The 16 bit field will allow the device powered by the Power Nut to be shutdown for 1 second to 18 2 hours with 1 second resolution Note that the operand 0x0000 is allowed If an operand of 0x0000 is received by the PowerNut the output connector will be energized If the system is designed such that a powered master is talking to the PowerNut while the downstream connector 1s de energized a shutdown for zero seconds command may be used to reenergize the downstream connector prior to the scheduled wake up time Set configuration word CMD 010 0x02 OPERAND 0x0000 To 0x00FF This command allows the behavior of the PowerNut to be modified through a configuration word If this command is received while the downstream power connector is de energized then the command is ignored The format of the configuration word is shown in the table ar fsp 10 o se rejsjajsjzjrjo Heart beat Low Voltage Low Voltage Low Voltage FUNCTION ua eae ae IE LED LED SIGNAL Threshold enable enable enable DEFAUL
27. nergized This indicates that the PowerNut s MOSFET switches Q2 and Q3 and PIC processor U2 are operating correctly You should use the DMM to verify the downstream voltage 1s approximately equal to the input voltage A 200 mV to 500 mV drop from the input connector to the downstream connector 1s normal This is mostly caused by D1 In a production setting D1 can be defeated by installing JP 1 or by installing a zero ohm shunt in an 0805 SMT package in R1 Next we setup a controller to talk to the PowerNut Getting Started 5 JK microsystems PowerNut User s Manual Controlling the PowerNut Remove Power Attach your controller to the logic signals on J3 Wire the system power so that both the controller and the PowerNut receive power from the power supply Do NOT attach your controller to the downstream power connector The following figure shows how the system should be setup J2 Flashlite 186 Downstream Voltage Indicator JK microsystems mad oad Power Supply 7 30 volts user supplied This example assumes the controller is a JK microsystems Flashlite 186 The Flashlite 186 must have a serial connection to a host PC This is not shown in the figure This connection 1s covered in the Flashlite 186 documentation The host PC should be running a terminal program such as Hyperterm to facilitate communication with the Flashlite 186 and provide a means of uploading programs to the Flashlite 186 If you have questions about
28. nvironments requiring fail safe performance such as in the operation of nuclear facilities aircraft navigation or communication systems air traffic control direct life support machines or weapons systems in which the failure of our hardware or software could lead directly to death personal injury or severe physical or environmental damage 11 Limited Warranty PowerNut User s Manual JK microsystems Table of Contents LO aa 1 Tal COMES aa ill i COCINE EP y o o In eee ees l PoU e E e E UC E E T EAE cei l OPTIO a E E E E A E EE E E tees 2 T O a T ET T ET E eee 2 Cai AA o ESTO E E ates 3 Tanne eyed aCe cor o NU OA No T E A 5 Conoce ONU 6 Powers Downsteani Controle ss 8 Periodically Rune an PC AMOI esa 9 AP e Pelo gs ne ns edo oa sg ee ee 10 Gencal TC Ob yO et AON tac rsce estes coc sos rade vote roe ryautsen sie ens gae nide vole weet yas taes soe sdous gas eask 10 APS and E a e a e a 15 COTA CAOS ode 17 Comman ds ande DS at 22 PP A e ro A 22 CEC OU AON Wy OC canelo cer centen sedans 22 Perrin LOW aly TS sia 24 Guidelines TOR Reabren bee 25 e Poo UE E In A 26 NUR ONM aio 26 WARIO SO E a sere eundial 2 CNOT asia 27 PC AC TONS E A no an 28 Mecca DANA iba 28 Contacta 29 Table of Contents 111 JK microsystems PowerNut User s Manual PowerNut User s Manual JK microsystems Overview The PowerNut gives system developers a clean tool to manage power in battery powered applications The PowerNut takes power f
29. ors that will carry a controller through a brown out condition for a short period of time tens or hundreds of milliseconds These controllers can randomly bounce around CLK and DATA_IO or DATA _IN for a fairly long period of time as power goes down or comes up For this reason the PowerNut ignores traffic on the clocked serial interface for one second after power is turned off or turned on to the downstream connector The PowerNut is capable of accepting and processing commands regardless of the state of downstream power A master controller capable of controlling power to devices other than itself may prematurely wake up a device by sending the appropriate command SHUTDOWN for ZERO seconds Communications Protocol 17 JK microsystems PowerNut User s Manual To help visualize communication blackout times the figure below illustrates a typical sleep wake cycle XN CLOCKED S READY SLEEP READY READY SERIAL BUS pono BUSIDLE CMD BLACKOUT BUS IDLE BLACKOUT BUS IDLE V DOWNSTREAM SECONDS 1 T_SLEEP T_SLEEP 0 5 T_SLEEP 1 5 T_WAKE 1 Just prior to O seconds Vin comes up This resets the PowerNut s processor and very shortly thereafter the downstream connector is energized At the 0 second mark in the figure downstream power 1s turned on and a second communications blackout starts At the 1 second mark the PowerNut will accept commands on the clocked serial bus Some arbitrary time later T_ SLEEP the master
30. rom the battery and supplies voltage regulated or raw battery voltage to downstream devices The primary system controller sends commands to the PowerNut indicating if power should be shutdown to downstream devices and for how long Typically the primary system controller will be downstream of the PowerNut and will therefore have the ability to shut itself off for a period of time However the PowerNut can also be used as a smart solid state relay to control power to subsystems that do not contain the primary system controller The PowerNut allows any controller or datalogger to gain efficient and reliable control over the system s power supply Many controllers and dataloggers can not shut themselves off or to wake up after time has elapsed The PowerNut uses an ultra low quiescent current regulator and a low power PIC processor running at 32768 Hz to supervise downstream power The PIC processor has a built in analog to digital converter that can be used for low battery detection Because the PIC never sleeps the clocked serial port can be used to wake up downstream devices The PowerNut is a reliable and versatile tool that provides complete control over your system s power Features Input voltage 5 30 volts if using the on board 5 volt regulator then 7 30 volts Capable of switching amp On board 5 volt 1 amp high efficiency switching regulator Downstream power can be regulated 5 volts or raw input voltage On
31. s driven low and DATA IO is not driven 10 Hardware PowerNut User s Manual JK microsystems PIC16LC710 The section entitled Communications Protocol spells out the bit level details of the message traffic The PIC16LC710 supervises the P channel MOSFETs Q2 amp Q3 These two MOSFETs are wired in parallel and will act as one switch When a command is received that tells the PowerNut to turn on or off power to the Downstream connector the PIC16LC710 does this by turning off the MOSFETs on or off The PowerNut has a on board 5 switching regulator capable of supplying up to 1 amp to downstream devices This is implemented with National Semiconductor s LM2575 Simple Switcher TM Hardware 11 JK microsystems PowerNut User s Manual The jumpers on JP3 allow the developer to select between switched raw voltage or regulated five volts as the voltage supplied to the downstream connector The following figure illustrates the wiring meee ee PIC16LC710 SWITCHING REGULATOR To configure the downstream voltage on J2 to be 5 volts JP3 1 and JP3 3 must be shorted along with JP3 2 and JP3 4 If the downstream voltage should be a switched version of the input voltage on J1 then JP3 4 and JP3 6 must be connected If the application requires both five volts and switched raw the PowerNut can provide this Configure JP3 to provide regulated 5 volts on the downstream connector J2 The application will have access to
32. sion 1 0 Copyright JK microsystems Inc Allrights reserved Printed in U S A Document Part No 94 0025 Published April 2003 JK microsystems PowerNut User s Manual Limited Warranty JK microsystems Inc warrants each PowerNut to be free from defects in material and workmanship for a period of 90 days from the date of purchase This warranty shall not apply to any unit which has been subject to misuse neglect accident or abnormal conditions of operation JK microsystems obligation under this warranty is limited to repairing or replacing at JK microsystems option any unit returned to the factory within 90 days of the date of purchase provided that JK microsystems determines that the unit is defective and has been used in compliance with the terms of this warranty If the failure has been caused by misuse neglect accident or abnormal conditions of operation repairs will be billed at a nominal cost The foregoing warranty is exclusive and in lieu of all other warranties expressed or implied including but not limited to any warranty of merchantability or fitness for any particular purpose JK microsystems shall not be liable for any special incidental or consequential damages whether in contract tort or otherwise Important Notice Life Support Mission Critical Applications This product is not fault tolerant and is not designed manufactured or intended for use or resale as on line control equipment in hazardous e
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