I2C tool usage
Table of Contents
i2c device
$ ls /dev/i2c* /dev/i2c-0 /dev/i2c-1
i2c-tools commands1
- i2cdetect – 用來列舉 I2C bus 和上面所有的裝置
- i2cdump – 顯示裝置上所有暫存器 (register) 數值
- i2cget – 讀取裝置上某個暫存器值
- i2cset – 修改裝置上的暫存器數值
i2cdetect
察看目前的系統有多少個 i2c bus
$ sudo i2cdetect -l
查詢 i2c-1 bus 上的所有設備，所得到的結果如下
# i2cdetect -y 1 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: 50 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- --
這樣代表共有兩個裝置掛在 i2c-1 上，其中標示為 UU 的代表該設備有被偵測到並正在被 kernel driver 使用著，而在這邊顯示 0x50 的就是所使用的 EEPROM。
i2cdump 查詢設備內所有暫存器
i2cdump 的使用方式如下:
Usage: i2cdump [-f] [-y] [-r first-last] I2CBUS ADDRESS [MODE [BANK [BANKREG]]] I2CBUS is an integer or an I2C bus name ADDRESS is an integer (0x03 - 0x77) MODE is one of: b (byte, default) w (word) W (word on even register addresses) s (SMBus block) i (I2C block) c (consecutive byte) Append p for SMBus PEC
# i2cdump -y 1 0x50 No size specified (using byte-data access) 0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef 00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 10: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 20: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 30: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 40: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 50: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 60: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 70: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 90: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ c0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
i2cset 修改設備暫存器數值
i2cset 的使用方式如下:
Usage: i2cset [-f] [-y] [-m MASK] I2CBUS CHIP-ADDRESS DATA-ADDRESS [VALUE] ... [MODE]
I2CBUS is an integer or an I2C bus name
ADDRESS is an integer (0x03 - 0x77)
MODE is one of:
c (byte, no value)
b (byte data, default)
w (word data)
i (I2C block data)
s (SMBus block data)
Append p for SMBus PEC
修改位於 i2c-1 上 0x50 的 0x12 暫存器，並將其數值修改為 5:
i2cset -f -y 1 0x50 0x12 5
# i2cdump -y 1 0x50 No size specified (using byte-data access) 0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef 00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 10: ff ff 05 ff ff ff ff ff ff ff ff ff ff ff ff ff ..?............. 20: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 30: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 40: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 50: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 60: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 70: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ 90: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ c0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
i2cget 來取得暫存器的數值
i2cget 命令格式如下:
Usage: i2cget [-f] [-y] I2CBUS CHIP-ADDRESS [DATA-ADDRESS [MODE]] I2CBUS is an integer or an I2C bus name ADDRESS is an integer (0x03 - 0x77) MODE is one of: b (read byte data, default) w (read word data) c (write byte/read byte) Append p for SMBus PEC
察看剛剛所設定的 0x12 暫存器:
# i2cget -y 1 0x50 0x12 0x05