The Valid hardware signal seems to move around, depending on what our I2S input is doing. For our current test we are driving the 5508B SDIN directly from a PCM1803A ADC. Both the 1803 and 5508 are I2S slaves, with the LRCK and BCK generated from our micro.
As I said, everything is basically working, but depending on the input to the ADC the Valid on the PWM sometimes toggles active/inactive. This typically happens when the device providing the analog input to the ADC is muted. This does not affect system functionality. Even though the Valid line toggles, audible output is as expected.
I have read the 5508 error status register at address 0x02, and it is always 0, even though the valid signal has toggled active/inactive numerous times.
1. Are there other conditions that cause Valid to change state, other than an error recorded in reg 0x02?
2. Might there me something going on with the PWM auto-mute, based on a low input value to the ADC?
