BBB-COMMS-2

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Tindie-mediums.png

BBB-COMMS-2-P418-720px.jpg

Features

Extensive I/O connections

  • (13) GPIOs - GVS (Ground/Voltage/Signal) pins
    • GVS (Ground/Voltage/Signal) pins
  • (3) UARTs - GVTxRx (Ground/Voltage/Tx/Rx) pins
    • GVTxRx (Ground/Voltage/Tx/Rx) pins
  • (1) I2C bus- GVSdaScl (Ground/Voltage/SDA/SCL) pins
    • GVSdaScl (Ground/Voltage/SDA/SCL) pins
    • Support for keyed headers
  • Cape Support features
    • Cape configuration EEPROM with write enable jumper
    • On I2C2 interface
  • Beaglebone Black form factor
  • Power LED

Headers and Connectors

BBB-COMMS-02 RevX1.PNG

Header

H1 - Write Enable Header

  • Install jumper onto header to allow writes to EEPROM
  • Remove jumper from header to prevent writes to EEPROM

Connectors

H2 - Power/Ground

  1. GND
  2. VCC
  3. No pin (KEY)

H3 - GPIO3_19, GPIO1_17

  1. GND
  2. VCC
  3. GPIO3_19 (P9_27)
  4. GPIO1_17 (P9_23)

H4 - UART1

  1. GND
  2. VCC
  3. UART1_TXD (P9_24)
  4. UART1_RXD (P9_26)

H5 - UART2

  1. GND
  2. VCC
  3. UART2_TXD (P9_21)
  4. UART2_RXD (P9_22)

H6 - I2C1

  1. GND
  2. VCC
  3. I2C1_SDA (P9_18)
  4. I2C1_SCL (P9_17)

H7 - EHRPWM1A, GPIO1_28

  1. GND
  2. VCC
  3. EHRPWM1A (P9_14)
  4. GPIO1_28 (P9_12)

H8 - EHRPWM1B GPIO3_19

  1. GND
  2. VCC
  3. EHRPWM1B (P9_16)
  4. GPIO3_19 (P9_27)

H9 - UART4

  1. GND
  2. VCC
  3. UART4_TXD (P9_C13)
  4. UART4_RXD (P9_C11)

H10 - KEY

  1. GND
  2. VCC
  3. No pin (KEY)

H11 - GPIO1_29

  1. GND
  2. VCC
  3. GPIO1_29 (P8_26)

H12 - GPIO2_1

  1. GND
  2. VCC
  3. GPIO2_1 (P8_18)

H13 - GPIO0_27

  1. GND
  2. VCC
  3. GPIO0_27 (P8_17)

H14 - GPIO1_14

  1. GND
  2. VCC
  3. GPIO1_14 (P8_16)

H14 - GPIO1_14

  1. GND
  2. VCC
  3. GPIO1_14 (P8_16)

H15 - GPIO1_15

  1. GND
  2. VCC
  3. GPIO1_15 (P8_15)

H16 - GPIO1_12

  1. GND
  2. VCC
  3. GPIO1_12 (P8_12)

H17 - GPIO1_13

  1. GND
  2. VCC
  3. GPIO1_13 (P8_11)

Schematics

Production Testing

Setup

  • Install BBB-COMMS-2 Unit Under Test (UUT) on BBB
  • Install shunt at H1 (Write Enable)
  • Ethernet connection to BBB
  • Power via 5V jack to BBB
  • Verify 3.3V PWR LED is lit
  • Log in via putty
    • User = root
    • Password = enter

GPIO Testing

  • Hook up LED-32 Card to these pins
D0 = "P8_26"
D1 = "P8_17"
D2 = "P8_15"
D3 = "P8_11"
D4 = "P9_23"
D5 = "P9_26"
D6 = "P9_22"
D7 = "P9_15"
D8 = "P9_12"
D9 = "P9_11"

D16 = "P8_18"
D17 = "P8_16"
D18 = "P8_12"
D19 = "P9_27"
D20 = "P9_24"
D21 = "P9_21"
D22 = "P9_16"
D23 = "P9_14"
D24 = "P9_13"
  • Run test via:
cd ~/pyBBB/BBB-COMMS-2/blink-BBB-COMMS-2/
python blink-BBB-COMMS-2.py
  • Ctrl-C to stop

EEPROM Programming

  • Go to directory
  • Program the EEPROM
  • Verify by typing
cd ~/pyBBB/BBB-COMMS-2/mkeeprom
cat data.eeprom > /sys/bus/i2c/devices/1-0054/eeprom
cat /sys/bus/i2c/devices/1-0054/eeprom | hexdump -C
  • Result should be like -
00000000  aa 55 33 ee 41 30 42 42  42 2d 47 56 53 2d 33 00  |.U3.A0BBB-COMMS-|
00000010  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |2...............|
00000020  00 00 00 00 00 00 58 31  00 00 4c 61 6e 64 20 42  |......X1..Land B|
00000030  6f 61 72 64 73 2c 20 4c  4c 43 42 42 42 2d 47 56  |oards, LLCBBB-CO|
00000040  53 2d 33 00 00 00 00 00  00 00 00 00 30 30 30 30  |MS-2........0000|
00000050  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
000000e0  00 00 00 00 00 00 00 00  00 00 00 00 00 fa 01 f4  |................|
000000f0  00 fa 00 00 ff ff ff ff  ff ff ff ff ff ff ff ff  |................|
00000100  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff  |................|
*
00008000
  • Remove WE jumper
  • Type
cat data.eeprom > /sys/bus/i2c/devices/1-0054/eeprom
  • Result should be error
root@BBB01:~/pyBBB/BBB-COMMS-2/mkeeprom# cat data.eeprom > /sys/bus/i2c/devices/1-0054/eeprom
cat: write error: Connection timed out
  • Prepare to re-run
  • Type
halt
  • Combined Copy/Paste
cd ~/pyBBB/BBB-COMMS-2/blink-BBB-COMMS-2
python blink-BBB-COMMS-2.py

cd ~/pyBBB/BBB-COMMS-2/mkeeprom/
cat data.eeprom > /sys/bus/i2c/devices/1-0054/eeprom
cat /sys/bus/i2c/devices/1-0054/eeprom | hexdump -C

I2C Testing

BBB-COMMS-2 I2CIO-8 Test-Setup 720px.png

Hardware

Enable I2C Bus

i2cdetect -y -r 2
  • Card shows up at 0x20
root@beaglebone:~/BBB/MCP23008# i2cdetect -y -r 2
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: 20 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

4 of I2CIO-8 cards

  • Connect 4 of I2CIO-8
    • I2C daisy-chain
    • Address jumpers set for 0x20-0x23
  • Enter
i2cdetect -y -r 2
  • Result shows cards at 0x20-0x23
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: 20 21 22 23 -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

Run Example Code

cd /root/BBB/MCP23008
root@beaglebone:~/BBB/MCP23008# ls -al
total 12
drwxr-xr-x  2 root root 4096 Apr 23  2014 .
drwxr-xr-x 17 root root 4096 Apr 23  2014 ..
-rwxr-xr-x  1 root root 1508 Apr 24  2014 MCP23008_ex.py
  • Run using
python MCP23008_ex.py

I2C Timing

  • 100 KHz

I2C Testing-01.PNG

Drivers / Example Code

Blink LEDs code

I2C Example Code

Issues

Rev X3

  • Fixed soldermask offset to = 0
  • Change some silkscreen sizes
    • BBB-COMMS-2 smaller
      • REV larger
  • Change silkscreen on I2C to I2C1

BBB-COMMS-02 RevX3.PNG

Rev X2

  • Skipped

Rev X1

  • No functional issues

BBB-COMMS-2 Assembly Sheet/Parts List

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