I continue working on my design and I have more Doubts. We have started from a one AD7768 (Eval CN0540) but we are designing to four channel because we need 4 IEPE independent channels. Also we need:
- Each channel must be isolated from the others.
- We have one crystal per channel so we haven´t a common MCLK. We are going to enable 4 clocks at the same time
-We need to switch off the unsued channels on each iteration (it can change in each cycle, on client demand)
We don´t know how to do 4 channels Synchronization because reading AD7768 datasheet we have two options:
1) If a signal that is synchronous to the base MCLK signal cannot be provided:
2 If a SYNC_IN signal synchronous to the base MCLK can be provided
We are in the First option (because we don´t have a SYNC_IN signal Synchronous to the base MCLK). The first option involves to have one of the ADC as a main device because it receives the first synchro signal and supply this signal to the others through the Sync_out. I think We can´t use the first option because we must switch off the channels doesn´t use in each measure cycle, so that we can´t choose an ADC as a main device due to It could be innactive in this measure cycle but it could be active 4 cycles after.
So, how can we Synchronise Our 4 channel design? Could anyone explain how and help us?
Thank you very much,