// https://forum.arduino.cc/t/arduino-uno-r4-spi-speed-configuration/1284260/3

#include <SPI.h>
#define CS		10

void setup() {
  SPI.begin();
  pinMode(CS, OUTPUT);
}

void loop() {
  int Data = 0x0A0B;      // 16BIT DATA
  
  SPI.beginTransaction(SPISettings(5000000, MSBFIRST, SPI_MODE0));

  digitalWrite(CS, LOW);
  SPI.transfer16(Data);     // 16BIT DATA
  
  delay(2000);

  digitalWrite(CS, HIGH);

  delay(2000);
  
  SPI.endTransaction();

  delayMicroseconds(500000);
}