I'm using SSP0 in 1768 to interface a serial SPI Flash memory. Pin SSEL0 is driven as a normal GPIO.
It works with lower clock frequencies (32MHz), but it doesn't work with higher frequencies (48MHz).
It seems I read data from the serial Flash shifted off by one bit when the frequency is high. I expect 0x4C51 (0100 1100 0101 0001), but I obtain 0xA6A8 (1010 0110 1010 1000).
I'm using serial Flash SST26VF064B from Microchip. I'm usign HIGH-SPEED READ command (0x0B) that should be possible to use at 48MHz.