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There are three I2C busses on the Ten64 board:

  • Primary/I2C1: Most sensors are on this bus
  • SPD/RTC/I2C3: DDR SPD and Real time clock (on a separate bus to facilitate EFI RTC implementation in the future)

    On RevA this was allocated exclusively to the TPM (Trusted Platform Module), on RevB the TPM moved to I2C1.

  • Peripheral/I2C4: For SFP+ EEPROM access

Both I2C1 and I2C4 are on the GPIO header.

List of I2C1 devices

I2C Address Part Description
0x00 (Not a device) SMBus broadcast address
0x18 EMC1704 U19 CPU Temperature diode + Board temperature diode
0x11 PAC1934 U41 Add in card current + 5V voltage
0x1A PAC1934 U20 CPU I/O rails: DDR VDD, Vpp, Vtt, 1.8V/OVDD
0x29 AT97SC3205T U23 Trusted Platform module
0x2F EMC2301 U59 Fan control (PWM) and tachometer
0x27 DS10DF410 U33 Retimer for 10 Gigabit/SFP+
0x4C EMC1813 U27 Temperature monitor for QSGMII PHYs
0x60 MP8869 CPU Core (1.0V) regulator
0x62 MP8869 3.3V Regulator
0x64 MP8869 5.0V Regulator
0x76 TCA9539 U39 GPIO Expander for SFP, LTE control etc.