hey guys I was working on a project previously where I needed to transmit a 10-bit signal from an analog/digital converter (ADC) to an Arduino Uno using the SPI protocol. Since SPI typically operates with a 16-bit data frame, I need to figure out how to pad or expand the 10-bit signal to fit into a 16-bit frame for transmission.

To simulate the ADC, I plan to use a second Arduino Uno as an SPI Master, while the receiving Arduino would act as an SPI Slave. Unfortunately, I only have one Arduino at the moment, so I can’t test my setup yet. I’m also a bit unsure about how to correctly expand the 10-bit signal for SPI transmission. What improvements can be made to ensure reliable SPI communication between the Master and Slave?

this is the code I’ve written for both the Master and Slave, but I could use some advice on how to implement the signal expansion and ensure proper communication between the two.

Master Arduino Code:

#include <SPI.h>
#define SS 10
#define MOSI 11

void setup() {
  pinMode(SS, OUTPUT);
  pinMode(MOSI, OUTPUT);
  SPI.beginTransaction(SPISettings(62500, LSBFIRST, SPI_MODE0));
}

void loop() {
  byte x = 0b00001101;  // Simulating 10-bit signal
  byte y = 0b11111111;  // Need to figure out how to pad or expand this
  
  digitalWrite(SS, LOW);
  SPI.transfer(x);
  SPI.transfer(y);
  digitalWrite(SS, HIGH);

  delay(1000);
}

Slave Arduino Code:

#include <SPI.h>
#define SS 10
#define MOSI 11

void setup() {
  pinMode(SS, INPUT);
  pinMode(MOSI, INPUT);
}

void loop() {
  byte x = SPDR;
  byte y = SPDR;
  
  Serial.print(x, DEC);  // Converting received data to decimal
  Serial.print(y, DEC);

  delay(1000);
}

Is there a way to test this code without a second Arduino, or can I simulate the SPI communication in some other way?