SdFat: only try to use DMA if it is implemented

STM32/libraries/SPI/src/SPI.h

@@ -4,6 +4,10 @@
 #include <Arduino.h>
 #include "stm32_gpio_af.h"
 
+#if defined(STM32F1) || defined(STM32F4)
+#define SPI_HAS_OLD_DMATRANSFER
+#endif
+
 // SPI_HAS_TRANSACTION means SPI has
 //   - beginTransaction()
 //   - endTransaction()

STM32/libraries/SdFat/src/SpiDriver/SdSpiSTM32.cpp

@@ -19,7 +19,6 @@
  */
 #if defined(ARDUINO_ARCH_STM32)
 #include "SdSpiDriver.h"
-#define USE_STM32F1_DMAC 1
 //------------------------------------------------------------------------------
 static SPIClass& pSpi = SPI;
 //------------------------------------------------------------------------------
@@ -66,7 +65,7 @@ uint8_t SdSpiAltDriver::receive() {
  */
 uint8_t SdSpiAltDriver::receive(uint8_t* buf, size_t n) {
   int rtn = 0;
-#if USE_STM32F1_DMAC
+#ifdef SPI_HAS_OLD_DMATRANSFER
   rtn = pSpi.dmaTransfer(0, buf, n);
 #else  // USE_STM32F1_DMAC
   //  pSpi.read(buf, n); fails ?? use byte transfer
@@ -91,7 +90,7 @@ void SdSpiAltDriver::send(uint8_t b) {
  * \param[in] n Number of bytes to send.
  */
 void SdSpiAltDriver::send(const uint8_t* buf , size_t n) {
-#if USE_STM32F1_DMAC
+#ifdef SPI_HAS_OLD_DMATRANSFER
   pSpi.dmaSend(const_cast<uint8_t*>(buf), n);
 #else  // #if USE_STM32F1_DMAC
   for (size_t i = 0; i < n; i++) {