Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 7/19/2024
Public

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5.9.6.2.2. Combined Formats

The I2C controller supports mixed read and write combined format transactions in both 7-bit and 10-bit addressing modes.

The I2C controller does not support mixed address and mixed address format—that is, a 7-bit address transaction followed by a 10-bit address transaction or vice versa—combined format transactions.

To initiate combined format transfers, the IC_RESTART_EN bit in the IC_CON register should be set to 1. With this value set and operating as a master, when the I2C controller completes an I2C transfer, it checks the transmit FIFO and executes the next transfer. If the direction of this transfer differs from the previous transfer, the combined format is used to issue the transfer. If the IC_RESTART_EN is 0, a STOP is issued followed by a START condition. Another way to generate the RESTART condition is to set the Restart bit [10] of the DATA_CMD register. Regardless if the direction of the transfer changes or not the RESTART condition is generated.