I am looking for a minimum circuitry possibly only wires connecting from the Nucleo 144 ARM to the IC. I want to send command on MOSI line from STM32 ARM to that device. I don't want to use logic analyser to test my SPI implementation but I want to use a simple IC to test it. Basically, something which does something to that device. What is the best device I can use it. I am planning to first test that device with Raspberry Pi3 by sending out commands over MOSI line from Raspberry PI to that simple device/IC.