COMe-bV26 - Rev. 1.0, User Guide
// 43
4/
System Resources
4.1.
I2C Bus
The following table specifies the devices connected to the accessible I2C bus including the I2C address. The I2C bus is
available at the COM Express® connector pin A83, I2C_CK and pin A84, I2C_DAT.
Table 19: I2C Bus Port Address
8-bit Address
7-bit Address
Used For
Available
58h
2Ch
Internally reserved
No
A0h
50h
Module embedded EEPROM (Eeep)
Yes
AEh
57h
Carrier board EEPROM
Option
64h
32h
External RTC
Option
4.2.
System Management (SM) Bus
The 8-bit SMBus address uses the LSB (bit 0) for the direction of the device.
Bit0 = 0 defines the write address
Bit0 = 1 defines the read address
The following table specifies the 8-bit and 7-bit SMBus write address for all devices.
Table 20: SMBus Address
8-bit Address
7-bit Address
Device
Description
5Ch
2Eh
Hardware Monitor NCT7802Y
Do not use this address for
external devices under any
circumstances!
