gz_25o waveform - Guzunty/Pi GitHub Wiki

Nothing particularly remarkable about this one. Four bytes clocked in through the SPI are mapped to 25 output pins. Only bit 0 of the fourth byte is used to set the 25th output. Since there are no inputs, miso is hardwired to '0'.

Because there are so many outputs, the bottom three bits didn't fit in the screen capture. Note that when the SPI selector goes idle, the byte count is reset. That is why the upper output bits take some time in the test case to get assigned a value.