uint32_t spiRx[256]; // Array to store received data
volatile int spiRxIdx = 0;  // Index to track how many items are in spiRx
volatile int spiRxComplete = 0;  // Flag to indicate when data is ready for printing

char buffer[2048]; // Character buffer to store formatted data
int indexbuf = 0; // Track current position in buffer

#include "SPISlave_T4.h"
SPISlave_T4<&SPI, SPI_8_BITS> mySPI;

IntervalTimer SPI_transfer;

void setup() {
  Serial.begin(921600);
  mySPI.begin();
  mySPI.swapPins(true);
  SPI_transfer.begin(ReceiveData, 10);  // run every 10000 microseconds
}

void loop() {
  // Other loop code can go here (if necessary)
}

void ReceiveData() {
  if (spiRxComplete) {
    indexbuf = 0;
    for (int i = 0; i < spiRxIdx; i++) {
       indexbuf += snprintf(buffer + indexbuf, sizeof(buffer) - indexbuf, "%02X ", (unsigned int)spiRx[i]);
    }    
    // Print the formatted buffer at once
    Serial.println(buffer);
    
    // Reset for the next round of data
    spiRxComplete = 0;
    spiRxIdx = 0;
  }
}