I2C
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 | 
| 0x11 | PAC1934 U41 | Add in card current + 5V voltage | 
| 0x18 | EMC1704 U19 | CPU Temperature diode + Board temperature diode | 
| 0x1A | PAC1934 U20 | CPU I/O rails: DDR VDD, Vpp, Vtt, 1.8V/OVDD | 
| 0x27 | DS10DF410 U33 | Retimer for 10 Gigabit/SFP+ | 
| 0x29 | AT97SC3205T U23 | Trusted Platform module | 
| 0x2D | USB5744 U42 | USB Hub (not applicable to RevD/OEM boards) | 
| 0x2F | EMC2301 U59 | Fan control (PWM) and tachometer | 
| 0x4C | EMC1813 U27 | Temperature monitor for QSGMII PHYs | 
| 0x61 | MP8869S | CPU Core (1.0V) regulator | 
| 0x63 | MP8869S | 3.3V Regulator | 
| 0x65 | MP8869S | 5.0V Regulator | 
| 0x76 | TCA9539 U39 | GPIO Expander for SFP, LTE control etc. | 
| 0x7E | LPC804 U14 | Board microcontroller |