Merge pull request #2299 from cmaglie/ide-1.5.x-spi-updates

Missing SPI Transaction API methods on Due (SAM3X)

Author: cmaglie

hardware/arduino/sam/libraries/SPI/SPI.cpp

@@ -62,12 +62,12 @@ void SPIClass::init() {
 #define interruptsStatus() __interruptsStatus()
 static inline unsigned char __interruptsStatus(void) __attribute__((always_inline, unused));
 static inline unsigned char __interruptsStatus(void) {
-  unsigned int primask, faultmask;
-  asm volatile ("mrs %0, primask" : "=r" (primask));
-  if (primask) return 0;
-  asm volatile ("mrs %0, faultmask" : "=r" (faultmask));
-  if (faultmask) return 0;
-  return 1;
+	unsigned int primask, faultmask;
+	asm volatile ("mrs %0, primask" : "=r" (primask));
+	if (primask) return 0;
+	asm volatile ("mrs %0, faultmask" : "=r" (faultmask));
+	if (faultmask) return 0;
+	return 1;
 }
 #endif
 
@@ -182,18 +182,70 @@ byte SPIClass::transfer(byte _pin, uint8_t _data, SPITransferMode _mode) {
 		d |= SPI_TDR_LASTXFER;
 
 	// SPI_Write(spi, _channel, _data);
-    while ((spi->SPI_SR & SPI_SR_TDRE) == 0)
-	;
-    spi->SPI_TDR = d;
-
-    // return SPI_Read(spi);
-    while ((spi->SPI_SR & SPI_SR_RDRF) == 0)
-	;
-    d = spi->SPI_RDR;
+	while ((spi->SPI_SR & SPI_SR_TDRE) == 0)
+		;
+	spi->SPI_TDR = d;
+
+	// return SPI_Read(spi);
+	while ((spi->SPI_SR & SPI_SR_RDRF) == 0)
+		;
+	d = spi->SPI_RDR;
 	// Reverse bit order
 	if (bitOrder[ch] == LSBFIRST)
 		d = __REV(__RBIT(d));
-    return d & 0xFF;
+	return d & 0xFF;
+}
+
+void SPIClass::transfer(byte _pin, void *_buf, size_t _count, SPITransferMode _mode) {
+	if (_count == 0)
+		return;
+
+	uint8_t *buffer = (uint8_t *)_buf;
+	if (_count == 1) {
+		*buffer = transfer(_pin, *buffer, _mode);
+		return;
+	}
+
+	uint32_t ch = BOARD_PIN_TO_SPI_CHANNEL(_pin);
+	bool reverse = (bitOrder[ch] == LSBFIRST);
+
+	// Send the first byte
+	uint32_t d = *buffer;
+	if (reverse)
+		d = __REV(__RBIT(d));
+	while ((spi->SPI_SR & SPI_SR_TDRE) == 0)
+		;
+	spi->SPI_TDR = d | SPI_PCS(ch);
+
+	while (_count > 1) {
+		// Prepare next byte
+		d = *(buffer+1);
+		if (reverse)
+			d = __REV(__RBIT(d));
+		if (_count == 2 && _mode == SPI_LAST)
+			d |= SPI_TDR_LASTXFER;
+
+		// Read transferred byte and send next one straight away
+		while ((spi->SPI_SR & SPI_SR_RDRF) == 0)
+			;
+		uint8_t r = spi->SPI_RDR;
+		spi->SPI_TDR = d | SPI_PCS(ch);
+
+		// Save read byte
+		if (reverse)
+			r = __REV(__RBIT(r));
+		*buffer = r;
+		buffer++;
+		_count--;
+	}
+
+	// Receive the last transferred byte
+	while ((spi->SPI_SR & SPI_SR_RDRF) == 0)
+		;
+	uint8_t r = spi->SPI_RDR;
+	if (reverse)
+		r = __REV(__RBIT(r));
+	*buffer = r;
 }
 
 void SPIClass::attachInterrupt(void) {