I want to use the AD7770 to sample a precise point in input signal. I have 1 DAC that change the test signal for different level, and I do a single measure to each point.
There is no information on the AD7770 datasheet about the process of the sampling, like if there sample & hold and how much time it should be stable. If I use the SPI there is no direct wire I can start sampling just the SPI word for SPI_SLAVE_MODE_ EN bit . But I see there is a SYNC_IN signal which can trigger the DRDY, but the data is not clear . Only Table 4 and Figure 4 put some information. so all the start process is ambiguous . Because I do single measure for each point I need it to be stable, so my questions:
1. How much time before sending the SPI_SLAVE_MODE_ EN bit =1, the input must be stable?
2. Does the first measure with new input level is correct, or there is a need for several measures depend on the difference between levels I have at the input and capacitive stable time inside the ADC?
3. Can I use the SYNC_IN as trigger for the measure? And if so
3a. What is the process, like first configure SPI_SLAVE_MODE_ EN bit. All that time hold SYNC_IN at "0" (measure disable) ,and the make it "1" .
3b. ANd even so there is a timing only for 16 kSPS, high resolution mode. and if I run at 2 kSPS, high resolution mode, does the delay make longer at the some ration?
Add some morte questions
[edited by: Barbar at 2:17 PM (GMT -5) on 12 Nov 2018]