Question
I wants to use SE pin to control the Sample rate, the internal sample rate is
8K, I hope I could give a 6.4K square wave to control SE pin to get 16 bits
data at 6.4KHz rate. The situation is when the frequency of square wave on SE
pin is slower than 2.6KHz, I could find output on SDOFS pin, however if the
frequency is higher than 2.6KHz then the parts do not work at all.
Could I control the sample rate by this method?
Answer
The SE pin is not designed to control the sample rate in this way and the
sampling does not begin until the SE pin is enabled. Due to the sigma delta
architecture it takes a while for the first sample to be generated and that is
why no samples are being seem at SE > 2.6kHz. The modulator does not have
enough time to start up completely and generate any samples.