software:programming:i2c:shell
Table of Contents
controlling i2c gpio via shell
Using kernel driver
For mcp23008:
p=232; z=/sys/class/gpio; echo $p > ${z}/export; echo out > "${z}/gpio${p}/direction"; echo 1 > "${z}/gpio${p}/value"; sleep 1; echo 0 > "${z}/gpio${p}/value"; echo $p > "${z}/unexport"
Setting MCP23008/MCP23017 gpio in user space via i2c
For mcp23008
# find out which i2c address the device listens to: i2cdetect -y 0 # you should find 0x20 # Set all bits from port a to output: i2cset -y 0 0x20 0x00 0x00 # Write value to register GPIOA (0x09) oder OLATA (0x0A) # For example: for bit 0, write: i2cset -y 0 0x20 0x14 0x01
For mcp23017
# find out which i2c address the device listens to: i2cdetect -y 0 # you should find 0x20 # Set all bits from port a to output: i2cset -y 0 0x20 0x00 0x00 # Write value to register GPIOA (0x12) oder OLATA (0x14) # For example: for bit 0, write: i2cset -y 0 0x20 0x14 0x01
Hardware detection
Color table:
| Bit | mcp23008 | mcp23017 |
|---|---|---|
| 1 | L_GRN | L-BLU |
| 2 | L_BLU | L-GRN |
| 4 | L_RED | L-RED |
| 8 | R_BLU | R-BLU |
| 16 | R_GRN | L-GRN |
| 32 | R_RED | L-RED |
| 64 | WHITE | WHITE |
| 128 | HEATR | HEATR |
# Detection for mcp23017: i2cset -y 0 0x20 0x00 0x00 i2cset -y 0 0x20 0x14 0x01 i2cget -y 0 0x20 0x14 # should give 0x01 on mcp23017 and 0x00 on mcp23008
References
software/programming/i2c/shell.txt · Last modified: 2017/03/07 22:18 by admin
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