BBB-COMMS-2

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

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 Pins

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 Pins

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

H8 - EHRPWM1B GPIO3_19 Pins

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

• Rev X1
• Rev X3

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 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

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

Hardware

• UUT
• I2CIO-8

Enable I2C Bus

• How-To enable the I2C devices on the BeagleBone Black Rev C
  • Enable the I2C devices on the BeagleBone Black
• Physically connected to I2C1 port on the BBB-COMMS-2 card but is I2C-2 from the software
• Probe I2C bus 2

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

• MCP23008_ex.py - 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

Drivers / Example Code

Blink LEDs code

• Blink LEDS on BBB-COMMS-2 GPIO lines

I2C Example Code

• MCP23008 Example code
  • Enable the I2C devices on the BeagleBone Black Rev C
  • 2nd method - BeagleBone Black I2C References
• Enable the I2C devices on the BeagleBone Black

Issues

Rev X3

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

Rev X2

• Skipped

Rev X1

• No functional issues

BBB-COMMS-2 Assembly Sheet/Parts List

• BBB-COMMS-2 Rev X1 Assembly Sheet
• BBB-COMMS-2 Rev X3 Assembly Sheet