I'm using the SPI lines to operate two DDS devices. The CS1 and CS2 lines are used.
In normal operation (normal temperature) these lines are in "high" state and when writing or reading from one of the DDS devices goes to "Low".
when running in cold temperature (0 - -5 deg c) these lines are always at "Low" and when writing or reading from the devices goes to "high" again and frame the data, at the end goes back to "low".
That situation causes all the devices that are connected to the SPI lines to be written all the time in parallel.
any idea ?