I2C Communication; Overview; Signal Description; I2C Address Map - Enclustra Mercury SA1 SoC Module User Manual

4 I2C Communication

4.1

Overview

The I2C bus on the Mercury SA1 SoC module is connected to the SoC device, EEPROM and RTC, and is
available on the module connector. This allows external devices to read the module type and to connect
more devices to the I2C bus.
Please note that the RTC must be configured correctly to use I2C interrupts - for details, refer to Section 2.21.
The I2C clock frequency should not exceed 400 kHz.
Warning!
Maximum I2C speed may be limited by the routing path and additional loads on the base board.
Warning!
If the I2C traces on the base board are very long, 100
module and I2C device on the base board.
4.2

Signal Description

Table 33 describes the signals of the I2C interface. All signals have on-board pull-up resistors to VCC_3V3.
All signals must be connected to open collector outputs and must not be driven high from any source.
I2C_INT# is an input to the SoC and must not be driven from the SoC device.
Level shifters are used between the I2C bus and the HPS pins, to allow I/O voltages lower than 3.3 V.
Signal Name
I2C_SDA
I2C_SCL
I2C_INT#
Table 33: I2C Signal Description
4.3

I2C Address Map

Table 34 describes the addresses for several devices connected on I2C bus.
D-0000-402-002
SoC Pin
HPS_GPIO55
HPS_GPIO56
HPS_GPIO54
41 / 49
series resistors should be added between
Connector Pin
A-113
A-111
A-115
Resistor
2.35 k pull-up
2.35 k pull-up
4.7 k pull-up
Version 06, 16.02.2021