ESP32 Forum

Hello,

i use esp-idf to write and read data over the I2C bus. To send or read data I have to call the function below:

esp_err_t i2c_master_cmd_begin(i2c_port_t i2c_num, i2c_cmd_handle_t cmd_handle, TickType_t ticks_to_wait)

Can someone explain the meaning of the parameter "ticks_to_wait"? As far as I know this function sends or writes all data in the command queue. Maybe this is a timeout parameter?

In the documentation I could only find the following information:

Parameters

• i2c_num: I2C port number
• cmd_handle: I2C command handler
• ticks_to_wait: maximum wait ticks.

Yes, it is a timeout value. If the queue is full for that amount of ticks, the call aborts instead of waiting longer.

That's already solved my question. Thanks for your reply!

ESP_Sprite wrote:Yes, it is a timeout value. If the queue is full for that amount of ticks, the call aborts instead of waiting longer.

hi jeroen, is it compare with clock stretching?

No, it has nothing to do with clock stretching (well, maybe very indirectly); it is just the timeout for pushing things into the FreeRTOS queue in the I2C driver.

ah, lifetime cycle for the task?
what happens if the timeout trigger? (the call aborts)
can we repeat ? repeat count?

... ( i am not deep in this theme ) ...

best wishes
rudi