Merge pull request adafruit#83 from adafruit/revert-77-master

Revert "Faster hardware SPI writes on SAMD"

Author: ladyada

Adafruit_SPIDevice.cpp

@@ -312,22 +312,6 @@ bool Adafruit_SPIDevice::write(uint8_t *buffer, size_t len,
       _spi->transferBytes(buffer, nullptr, len);
     }
   } else
-#elif defined(ARDUINO_ARCH_SAMD) && defined(_ADAFRUIT_ZERODMA_H_)
-  // The variant of transfer() used below currently only exists in the Adafruit
-  // core. It causes a build failure when building against the main Arduino SAMD
-  // core. Unfortunately there doesn't seem to be a supported #define that this
-  // code can use to tell which core it's building against. This hack (checking
-  // for the include guard that gets defined when the Adafruit core's SPI.h
-  // includes Adafruit_ZeroDMA.h) works for now, but it should be improved when
-  // possible.
-  if (_spi) {
-    if (prefix_len > 0) {
-      _spi->transfer(prefix_buffer, nullptr, prefix_len);
-    }
-    if (len > 0) {
-      _spi->transfer(buffer, nullptr, len);
-    }
-  } else
 #endif
   {
     for (size_t i = 0; i < prefix_len; i++) {
@@ -433,19 +417,6 @@ bool Adafruit_SPIDevice::write_then_read(uint8_t *write_buffer,
       _spi->transferBytes(write_buffer, nullptr, write_len);
     }
   } else
-#elif defined(ARDUINO_ARCH_SAMD) && defined(_ADAFRUIT_ZERODMA_H_)
-  // The variant of transfer() used below currently only exists in the Adafruit
-  // core. It causes a build failure when building against the main Arduino SAMD
-  // core. Unfortunately there doesn't seem to be a supported #define that this
-  // code can use to tell which core it's building against. This hack (checking
-  // for the include guard that gets defined when the Adafruit core's SPI.h
-  // includes Adafruit_ZeroDMA.h) works for now, but it should be improved when
-  // possible.
-  if (_spi) {
-    if (write_len > 0) {
-      _spi->transfer(write_buffer, nullptr, write_len);
-    }
-  } else
 #endif
   {
     for (size_t i = 0; i < write_len; i++) {