Arduino Uno SPI test & demo board

Built using an Arduino UNO prototype sheild board with shift registers and NAND gates 8-bit data can be transmitted and viewed and an 8-bit switch read and printed to a serail monitor.  I used what I had to hand including CMOS and Bipolar TTL devices.  The sheild plugs into a standard Arduino UNO and makes all necessary connections via this interface.  Latest sketch at: https://github.com/BenthamITServices/Arduino_2/tree/main/ArduinoIDE-UNO/SPI_Transmit_Receive_test_sheild