Alive Stack User Manual
Contents
1. ALIVE STACK User Manual Living Machines Group February 10 2003 1 Overview This document provides specification for the use and design of the Alive Stack This document supporting code and schematics can be found at lima alive stack on the MIT AI Lab network 2 Stack for Windows The Alive Stack can be monitored and debugged via a graphical user interface This user interface is documented in the Creature Language manual A Windows port of the interface is available at xxx However the following additional steps are necessary before the Windows port can be used 1 Install the latest version of Cygwin to the host PC a Unix for Windows toolset http www cygwin com a During installation be sure that the X Server XFree86 is also installed 3 Pic Programming The Warp13a Pic programmer www newfoundelectronics com is currently the default programmer for the Alive Stack due mostly to its command line interface availability for Linux and its inte gration into the CCS Pic C compiler environment and the MPLAB environment However other programmers should work equally well Programming is done via the In Circuit Serial Programmer ICSP and is not done via Low Voltage Programming The standard CONFIG settings for Pic programming we use are config word 0x3F32 which corresponds to 1 Watchdog Timer Off 2 Low Voltage Programmer Off 3 Power up Timer On 4 Brownout Detect Off 5 Crystal select HS 20Mhz 6 Code2. Data Protect Off 7 Flash Program Memory On Molex Hirose MQ1 72X 4SA CV 5 pin connector 4 pin connector OS Pind Rb Ro7 Pin2 Vop __ Rb6 Pin 1 GND Figure 1 Programming cable pinout for Warp13 programmer 8 Flash Debug Mode Off Each peripheral device will need the firmware downloaded to it The firmware is written in assembly and or in CCS Pic C Each peripheral device in the stack needs one or more unique IDs This should be set in the firmware the firmware recompiled and programmed to the peripheral device Refer to the firmware for setting the device ID 4 Timing and Memory Considerations Bandwidth and memory constraints place some limitations on the Alive Stack The communication speed between the Rabbit or host PC and the Alive Stack is 115 2Kbps The Creal bios sends update data packets to the Alive Stack at arate of 64H z To satisfy this polling rate the Alive Stack can only support approximately 115200 10 64 180 total bytes for the upstream and downstream packet size fast and slow packet combined The implementation of the communication protocol on the Carrier Board imposes a memory con straint on the system The downstream packets are buffered on the Carrier Board This buffer size is limited to 256 bytes Because of the Rabbit Alive Stack bandwidth constraint this limitation can effectively be ignored Memory constraints also limit the total number of peripheral devices on the Al
3. bits of the most signficant byte MSB are set to 0 Downstream Packet oo Periph ID Upstream Packet Reply from periph ID A Byte Definition CIMS S Ch MSB_ LSB o Cho LSB _ i2 MSB MSB Ch8 MSB Ch9 MSB Ch13 MSB eed 6 Cm2 MSB_ eal 9 ais P Chie SB 1 1 1 1 14 12 Bus Top Side Pinl Gnd Pin2 Signal Pin3 Pwr wn O N wn ON O ZIN Bus GAS AA Signal Pulldown 1206 Resistor io Signal Pullup 1206 Resistor oe Bottom Side Viewed through top O W wn n ons VN Figure 5 Analog Sensor Board pinout Signal pullup pulldown can be achieved by soldering a 1206 package resistor across 2 header pins as illustrated 6 2 11 Power The Analog Sensor Board electronics are powered by the Alive Stack bus It draws xx mA The sensor power is provided externally This external power supply is not optoisolated from the Alive Stack power It should be a clean regulated supply of 5 0V dc 6 2 12 Firmware The Analog Sensor Board should be programmed with alive_anlog_periph c The firmware treats the board as two independent peripheral devices of 8 channels each Consequently two peripheral IDs need be specified in the firmware If 8 or less sensor channels are used then only one peripheral need be specified in Creal The peripheral may be eithe
4. breakout so that it can mount against the robot Refer to the periph_template ddb Protel document for a template design when designing new board Likewise refer to periph_template c when designing new board firmware 6 Board Specifications 6 1 Carrier Board 6 1 1 Overview The Carrier Board provides an interface between the host and the peripheral boards The two on board Pic 16F876 microcontrollers implement the Alive Stack communication protocol as specified in the Creal Communication Protocol documentation Typically the host will be a Rabbit micro controller running Creal In this case the details of the protocol are not important as the Creal Bios will take care of communication between the Rabbit and the Carrier Board Alternatively a host PC may be interfaced with the Alive Stack using the RS232 Board In this case it is the responsibility of the host PC to handle communication with the Carrier Board 6 1 2 Connectors J6 Master Programming Header Uses standard programming connector Programs alive_master c Carrier Board firmware Pin Definition 1 GND 2 12V Prgm Voltage VPP Pues RB6 In Circuit Prgm 4 RB7 In Circuit Prgm J7 Slave Programming Header Uses standard programming connector Programs alive_slave c Carrier Board firmware Pin Definition GND 12V Prgm Voltage VPP RB6 In Circuit Prgm RB7 In Circuit Prgm J3 Serial Port C Header J2 Serial Port D Header Breaks out Rabbit Serial Port C Breaks
5. hould be orange 3 At startup the Carrier Board s Master heartbeat LED will flash rapidly When table initial ization has occured via the Rabbit the LED will flash at half its previous speed 6 1 7 Power Board 6 1 8 Overview The Power Board sits at the bottom of the Alive Stack It provides power to the Alive Stack bus which in turn powers most all of the electronics on the Alive Stack Two options of power are available One is an optoisolated DC DC 5Vdc converter which is recommended A second option is a 5Vdc voltage regulator which is not optoisolated On board jumpers select which option is to be used While the Power Board can be populated with both power options only one is necessary The 5Vdc voltage regulator is a less expensive more compact and more readily available option while the DC DC converter provides power source noise isolation The Power Board also contains test points for debugging a power reset switch and terminating resistors for the RS485 bus 6 1 9 Connectors 2mm discrete wire header Pin Definition J3 J6 Test Points Pin Definition 6 1 10 Power Power Specifications Supply Output Pat Regulated G2dVo TMD DC DC Converter 9 18Vdc 1000ma Tri Mag TDB5W 1205S Refer to the datasheet for each component for more information Bus Top Side O Optoisolated Jumper Stings Bottom Side Viewed through top 00 ON Regulator Jumper Setting
6. ive Stack to be 32 Communication between the Carrier Board and the peripheral devices on the Alive Stack occurs at 250K bps It is important to keep this in mind when designing a peripheral board The typical peripheral board uses a 20Mhz Picl6F876 which has an instruction cycle time of 0 2us The time between two successive bytes arriving on the peripherals UART is 11 250000 44us Thus the peripheral has approximately 200 instruction cycles to perform communciation housekeeping and to implement the desired peripheral functionality 5 Peripheral Board Design A peripheral board designed to fit into the Alive Stack should conform to the current Alive Stack form factor and footprint A template PCB layout is available The RS485 bus programming header and auxillary power connectors have been standardized and all future peripherals should use these connectors In addition to maintain clearance between adjacent boards in the Alive Stack we follow the convention that tall board components should be placed on the bottom of the board For example all programming headers and power conectors should be on the bottom of the board The top edge of the Alive Stack the edge with the mounting hole is the breakout for the pro gramming header and auxillary power connectors The location of these connectors should follow the existing standard as best possible The two side short edges provide breakout for i o etc The bottom edge shouldn t be used for
7. ly this pulse width has a range of 1 2ms which corresponds to a physical range of 0 90 degrees However these number vary between manufacturers and greater ranges up to 180 degrees can be obtained by tuning the pulse width range in firmware Refer to alive_servo_periph c for an example of how to do this The peripheral may be either fast or slow In Creal a typical definition might look like texttt defperipheral servoboard fast id 1 default type uns8 write texttt chi 128 ch2 128 ch3 128 ch4 128 ch5 128 ch6 128 ch7 128 ch8 128 10 6 2 6 Notes 1 At startup the default servo position is dead center corresponding to a positional value of 128 2 Care should be taken that the servo connector is not installed backwards Refer to the board diagram ref and the board silkscreen to ensure proper orientation 6 2 7 Analog Sensor Board 6 2 8 Overview The Analog Sensor Board interfaces with up to 16 sensors The onboard ADC provides 12 bit sampling resolution on voltages 0 5Vdc Sensor wiring is simplifed by provision of indvidual GND and 5Vdc PWR pins for each input channel An external power supply is required however 6 2 9 Connectors Pin Definition Pm Defmition 11 J3 Power Header External Sensor Power 5 0Vdc 2mm discrete wire header Pin Definition Sensor GND 6 2 10 Packets Each channel returns 2 bytes of data The ADC provides 12 bit resoultion The upper 4
8. out Rabbit Serial Port D 2mm pitch standard header 2mm pitch standard header Pin Definition Pin Definition GND VOC J4 J5 Rabbit Header Mates with Rabbit Micro Align Rabbit mounting hole with Carrier Board mounting hole Pin Definition J4 1 26 Refer to Rabbit documentation for J4 pinout J5 1 26 Refer to Rabbit documentation for J5 pinout 6 1 3 Packets The Carrier Board recieves data packets from the host according to the Creal Communication Protocol It replies with continuous stream of data packets from the Alive Stack Refer to the Creal Communication Protocol documentation for more information J5 J4 Top Side Master Slave F O N ZIN Bus Bottom Side J3 Viewed through top C 3 Serial C fj Fa J2 serial D 1 m Figure 2 Carrier Board Pinout 6 1 4 Power The Carrier Board is powered by the Alive Stack bus It draws xx mA 6 1 5 Firmware There are two onboard Pics denoted Master and Slave They are programmed with alive master c and alive_slave c respectively Excepting upgrades in firmware these should not need reprogram ming once initially programmed 6 1 6 Notes 1 The Carrier Board places some memory constraints on total packet size on the Alive Stack Refer to ref for more information 2 The Master heartbeat LED should be blue and the Slave heartbeat LED s
9. r fast or slow In Creal a typical definition might look like defperipheral sensor_bank_a fast id 1 read adc1 adc2 adc3 adc4 adc5 adc6 adc7 adc8 defperipheral sensor_bank_b fast id 2 read adc9 adc10 adc11 adc12 adc13 adc14 adc15 adc16 13 6 2 13 Notes 6 3 RS232 Board 6 3 1 Overview The RS282 Board allows the Alive Stack to be used with a host PC instead of the Rabbit The RS232 Board matches the header footprint of the Rabbit such that it can be plugged into the Carrier Board where the Rabbit normally resides The RS232 Board provides RS485 RS 232 conversion between the Alive Stack and the host PC s serial port 6 3 2 Notes 1 This current version of this board is not compatible with the latest version of the Alive Stack To be done soon 7 Schematics 8 Parts Lists 9 Vendors 14
10. s EO OO OOO Vec TX RX GND Figure 3 Power Board pinout The Alive Stack power consumption characteristics are 6 1 11 Notes 6 2 RC Servo Board 6 2 1 Overview The RC Servo Board controls up to 8 RC servos using pulse code modulation The board uses standard 0 1 inch 3 pin connectors that are pin compatible with most servos 6 2 2 Connectors Pin Definition CS J7 J10 Servo Header Breaks out 8 Servo Channels 0 lin pitch standard header Pin Definition N W Pin Definition 6 2 3 Packets Downstream Packet yie here is no upstream data Top Side Bottom Side Viewed through top Figure 4 RC Servo Board Pinout 6 2 4 Power The RC Servo Board electronics are powered by the Alive Stack bus It draws xx mA The RC servo power is provided externally This external power supply is optoisolated from the Alive Stack power It should match the specifications provided by the servo vendor but is usually in the range of 4 5 6 0V de 6 2 5 Firmware The RC Servo Board should be programmed with alive_servo_periph c The position of an RC servo is specified by an 8 bit number The firmware may soon be upgraded to provide 12 bit resoultion This positional value is translated in the firmware into a Pulse Code Modulation pulse width Typical
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