Ethernet2 (UDP) SPI transfers have a lot of dead time

Hardware Arduino Due
37

Yeah, now that's more like it!

SPI SCK @ 42MHz, no deadtime, 100 bytes transferred in 19.04µs!

5.25 MBps (42Mbps)

#include <TurboSPI.h>

TurboSPI    g_SPI;
DigitalPin  g_PinCS, g_PinRS;
uint8_t     g_Buffer[100];  // some data buffer to transfer
uint8_t     g_Divisor = 2;  // transfer speed set to MCU's clock divide by 2

void setup()
{
  // setup pins
  g_PinCS.Begin(45);
  g_PinRS.Begin(47);

  g_PinCS.PinMode(OUTPUT);
  g_PinRS.PinMode(OUTPUT);

  // setup SPI
  g_SPI.Begin();

  // fill the buffer with data
  for (uint8_t i = 0; i < sizeof(g_Buffer); i++) {
    g_Buffer[i] = i + 1;
  }
}

void loop()
{
  // setup speed and select slave
  g_SPI.Init(g_Divisor);
  g_PinCS.Low();

  // set some pins
  g_PinRS.High();

  // transfer data to slave
  g_SPI.Send(g_Buffer, sizeof(g_Buffer));

  // unselect slave
  g_PinCS.High();
}