I2C¶
Available I2C buses¶
List of available I2C buses on DART-MX93 and Sonata-Board:¶
# ls -l /dev/i2c-*
crw------- 1 root root 89, 0 Dec 21 16:31 /dev/i2c-0
crw------- 1 root root 89, 2 Dec 21 16:31 /dev/i2c-2
crw------- 1 root root 89, 4 Dec 21 16:31 /dev/i2c-6
System class:
I2C devices per bus¶
Scan bus 0:
# i2cdetect -y -r 0
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- UU -- -- -- -- -- -- -- -- -- 2c -- -- --
30: -- -- -- -- -- -- -- -- UU -- -- -- UU UU -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- 54 55 -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
Scan bus 2:
# i2cdetect -y -r 2
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- UU -- -- -- -- --
20: -- -- -- -- -- UU -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- 52 53 -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
Scan bus 6:
# i2cdetect -y -r 6
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: UU UU -- -- -- -- -- -- -- -- -- -- -- -- UU --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
When the device is marked with "UU" it means that a driver is using it. When the device is marked with numbers it means that no driver is using it.
Reading / Writing from an I2C device¶
Variscite includes I2CTools as a part of the default file system build, examples of optional commands: i2cdump - dump the content of an I2C device i2cset - write a single character to an I2C device i2cget - read a single character to an I2C device
In addition follow 'C' code example as describe in the linux kernel documentation : https://www.kernel.org/doc/Documentation/i2c/dev-interface
Variscite's system integrated I2C devices¶
Note: Do not write to Variscite's on-SOM EEPROM or you will damage the SOM!
I2C-0 0x22 - PCA9534 GPIO expander on carrier board
I2C-0 0x38 - Capacitive touch controller on kit display
I2C-0 0x3c – MIPI-CSI camera on expansion board
I2C-0 0x3d – USB Type C controller on carrier board
I2C-0 0x54 - EEPROM on carrier board
I2C-0 0x55 - EEPROM on carrier board
I2C-0 0x68 - RTC on carrier board
I2C-2 0x1a - Audio codec on SOM
I2C-2 0x25 - PMIC on SOM
I2C-2 0x52 - EEPROM on SOM. Don't modify!
I2C-2 0x53 - EEPROM on SOM. Don't modify!
I2C-6 0x20 - PCAL6408 GPIO expander on carrier board
I2C-6 0x21 - PCAL6408 GPIO expander on carrier board
I2C-6 0x2e - ST33KTPM2I TPM 2.0 on carrier board