I am currently writing C++ code to utilize SPI protocol. I am using popular library as a guide. Run into few questionable areas and after some discussion on the library board forum I have been told "it is an internal problem " ( of the hardware ). To be specific - using MOSI "port" I can "write" to hardware and monitor the outcome via software. Neither MOSI or CLK ports are connected to any SPI slave device. I have no issues there. When I "read" MISO port,again not connected to slave device , I do expect no valid data - no actual MISO signal. That is fine.
The master DOES NOT send CLK at all! The master / device empties buffer(s) which are filled DURING the "write" cycles DURING "read" from slave operation.
My actual general question I would like to get answered is
Does SPI master require physical connection to slave to send CLK to slave during slave read operations ?
Per SPI documentation - master sends CLK during "write" to slave and sends CLK during "read" from salve. Master SPI is the CLK source. Only the SPI "write" part works as expected.