Posted on August 24, 2016 at 01:18Greetings
Using the HAL function HAL_SPI_TransmitReceive() to read erased data (i.e. all FF's) data from an external serial NOR device I get a block of 0's at either the start or the end of a 256 byte read. Using 1 byte at a time with this function or bit banging GPIO all works OK.
Checking the signals on a Logic Analyser, all look the same (i.e. correct) in the 3 cases defined above, in particular MISO is a solid '1' so should be interpreted as a 0xff for each received bye.
If I use HAL_SPIEx_FlushRxFifo() prior to the multi-byte call to HAL_SPI_TransmitReceive() then I eliminate the leading 0's but I get trailing 0's. In both cases I get a timeout return from the function even though I can see on the L.A trace that the data has completed transfer after only 20% of the time allowed.
Setting the transmit buffer to all 0's or all 1's makes no difference (as expected as that is the data going out on MOSI).
As expected, I really need to get this working (I'd prefer with DMA but that is another bug in the HAL) so I'm open to ideas maybe extracting bits from std-perph-lib that are known to work.
Cheers
#spi
