ADAU1701 I2C read

Hello Dave

Thanks for the detailed answer.

The main point is the missing ACK from the ADAU1701 device, if we look closly at fig 21 the first frame ends with such an ACK (which the I2C master would sample on the 9th rising edge of SCL). That is before we can continue with the additional frames of the exact register address inside the ADAU1701.

In other words, the first frame is to select teh ADAU1701 on the I2C bus, with the next 2 frames to select the exact ADAU1701 register . This is true for both read and write operations. the rest of the frames differ between read/write operations. Only on frame 4 you send a repeated start condition. The waveform indicates that the master sent a stop condition as it got a NACK. I believe that this was the right responce.

The same first frame with a write operation resulted in the ADAU1701 sending the required ACK.

I will try to check if the timing is marginal and is the culprit.

Is there anything we're missing?

Does the ADAU1701 needs an initial write before a read?

Thanks

Alon

Hello Dave

Thanks for the detailed answer.

The main point is the missing ACK from the ADAU1701 device, if we look closly at fig 21 the first frame ends with such an ACK (which the I2C master would sample on the 9th rising edge of SCL). That is before we can continue with the additional frames of the exact register address inside the ADAU1701.

In other words, the first frame is to select teh ADAU1701 on the I2C bus, with the next 2 frames to select the exact ADAU1701 register . This is true for both read and write operations. the rest of the frames differ between read/write operations. Only on frame 4 you send a repeated start condition. The waveform indicates that the master sent a stop condition as it got a NACK. I believe that this was the right responce.

The same first frame with a write operation resulted in the ADAU1701 sending the required ACK.

I will try to check if the timing is marginal and is the culprit.

Is there anything we're missing?

Does the ADAU1701 needs an initial write before a read?

Thanks

Alon