AnsweredAssumed Answered

How do you synchronize conversions from 2 AD7799 converters

Question asked by rockybooth on May 6, 2014
Latest reply on May 17, 2014 by rockybooth

I have been using AD7799 converters for several years in the continuous run mode.  Now I have an application that requires two AD7799 converters connected to the same microprocessor, and sharing data in, data out, and clock SPI lines.  Separate CS lines for each. I will run at 125Hz, and need to sync the two converters within a few microseconds collecting data over an extended period of time.  I am planning on starting a single conversion by writing to both AD7799 mode registers at the same time, but I realize this leaves the data out lines active from each converter and they are tied together.  Both lines should be at the same state so I presume this should not matter.  Then the CS lines would go high and one converter polled for conversion complete, at which point each converter would be queried separately for its data.  The process would repeat and the throughput is anticipated to be somewhat less than 62.5Hz, which is ok, as I assume that to keep the converters in sync they must reinitialize after every conversion.

Does anyone see any problems with this approach, or could suggest a different approach, hopefully without changing the layout which has already been built?

Thanks in advance for any help or suggestions.