Respond to SPI Data

The Serial Peripheral Interface (SPI) is a protocol for communication between a master and a few slave devices. It is very fast because the communication is synchronous and the clock is maintained by the master device. The master decides when to talk with each slave, and the data transfer happens on the Master-In-Slave-Out (MISO) and Master-Out-Slave-In (MOSI) lines.

In this example, code is deployed to an Adafruit ItsyBitsy 32u4 - 5V to read the temperature from a MAX6675 SPI sensor, turn on an LED when the temperature is within the desired range and turn on a buzzer when it is not.

The systems model with one input for the temperature and two outputs for the LED and buzzer.

The MAX6675 sends the data as two bytes.

The conversion from bytes to obtain the temperature in °C.

Specify the sensor as an SPI slave device with pin A4 as the slave select pin.

The LED output.

The buzzer output.

The complete microcontroller specification.

Deploy the code.