Cyclone® V Hard Processor System Technical Reference Manual

ID 683126
Date 8/28/2023
Public
Document Table of Contents

21.5.3. Disabling the I2C Controller

The register IC_ENABLE_STATUS is added to allow software to unambiguously determine when the hardware has completely shutdown in response to the IC_ENABLE register being set from 1 to 0. †

  1. Define a timer interval (ti2c_poll) equal to the 10 times the signaling period for the highest I2C transfer speed used in the system and supported by the I2C controller. For example, if the highest I2C transfer mode is 400 Kbps, then ti2c_poll is 25 us. †
  2. Define a maximum time-out parameter, MAX_T_POLL_COUNT, such that if any repeated polling operation exceeds this maximum value, an error is reported. †
  3. Execute a blocking thread/process/function that prevents any further I2C master transactions to be started by software, but allows any pending transfers to be completed.
    • This step can be ignored if the I2C controller is programmed to operate as an I2C slave only. †
  4. The variable POLL_COUNT is initialized to zero. †
  5. Set IC_ENABLE to 0. †
  6. Read the IC_ENABLE_STATUS register and test the IC_EN bit (bit 0). Increment POLL_COUNT by one. If POLL_COUNT >= MAX_T_POLL_COUNT, exit with the relevant error code. †
  7. If IC_ENABLE_STATUS[0] is 1, then sleep for ti2c_poll and proceed to the previous step. Otherwise, exit with a relevant success code. †