added SPI data size management to allow true 16 bit transfer

Author: stevstrong

STM32F1/libraries/SPI/src/SPI.cpp

@@ -142,15 +142,14 @@ SPIClass::SPIClass(uint32 spi_num) {
  * Set up/tear down
  */
 void SPIClass::updateSettings(void) {
-	uint32 flags = ((_currentSetting->bitOrder == MSBFIRST ? SPI_FRAME_MSB : SPI_FRAME_LSB) | SPI_DFF_8_BIT | SPI_SW_SLAVE | SPI_SOFT_SS);
+	uint32 flags = ((_currentSetting->bitOrder == MSBFIRST ? SPI_FRAME_MSB : SPI_FRAME_LSB) | _currentSetting->dataSize | SPI_SW_SLAVE | SPI_SOFT_SS);
 	#ifdef SPI_DEBUG
 	Serial.print("spi_master_enable("); Serial.print(_currentSetting->clockDivider); Serial.print(","); Serial.print(_currentSetting->dataMode); Serial.print(","); Serial.print(flags); Serial.println(")");
 	#endif
 	spi_master_enable(_currentSetting->spi_d, (spi_baud_rate)_currentSetting->clockDivider, (spi_mode)_currentSetting->dataMode, flags);
 }
 
 void SPIClass::begin(void) {
-	
     spi_init(_currentSetting->spi_d);
     configure_gpios(_currentSetting->spi_d, 1);
     updateSettings();
@@ -161,7 +160,7 @@ void SPIClass::beginSlave(void) {
         ASSERT(0);
         return;
     }
-    uint32 flags = ((_currentSetting->bitOrder == MSBFIRST ? SPI_FRAME_MSB : SPI_FRAME_LSB) | SPI_DFF_8_BIT | SPI_SW_SLAVE);
+    uint32 flags = ((_currentSetting->bitOrder == MSBFIRST ? SPI_FRAME_MSB : SPI_FRAME_LSB) | _currentSetting->dataSize | SPI_SW_SLAVE);
     spi_init(_currentSetting->spi_d);
     configure_gpios(_currentSetting->spi_d, 0);
 	#ifdef SPI_DEBUG
@@ -216,6 +215,7 @@ void SPIClass::setBitOrder(BitOrder bitOrder)
 */
 void SPIClass::setDataSize(uint32 datasize)
 {
+	_currentSetting->dataSize = datasize;
 	uint32 cr1 = _currentSetting->spi_d->regs->CR1 & ~(SPI_CR1_DFF); 
 	_currentSetting->spi_d->regs->CR1 = cr1 | (datasize & SPI_CR1_DFF);
 }
@@ -268,6 +268,7 @@ void SPIClass::beginTransaction(uint8_t pin, SPISettings settings)
 	//digitalWrite(_SSPin,LOW);
 	setBitOrder(settings.bitOrder);
 	setDataMode(settings.dataMode);
+	setDataSize(settings.dataSize);
 	setClockDivider(determine_baud_rate(_currentSetting->spi_d, settings.clock));
 	begin();
 }

STM32F1/libraries/SPI/src/SPI.h

@@ -96,28 +96,40 @@
 #define SPI_MODE2 SPI_MODE_2
 #define SPI_MODE3 SPI_MODE_3
 
+#define DATA_SIZE_8BIT SPI_CR1_DFF_8_BIT
+#define DATA_SIZE_16BIT SPI_CR1_DFF_16_BIT
+
 class SPISettings {
 public:
 	SPISettings(uint32_t clock, BitOrder bitOrder, uint8_t dataMode) {
 		if (__builtin_constant_p(clock)) {
-			init_AlwaysInline(clock, bitOrder, dataMode);
+			init_AlwaysInline(clock, bitOrder, dataMode, DATA_SIZE_8BIT);
+		} else {
+			init_MightInline(clock, bitOrder, dataMode, DATA_SIZE_8BIT);
+		}
+	}
+	SPISettings(uint32_t clock, BitOrder bitOrder, uint8_t dataMode, uint32_t dataSize) {
+		if (__builtin_constant_p(clock)) {
+			init_AlwaysInline(clock, bitOrder, dataMode, dataSize);
 		} else {
-			init_MightInline(clock, bitOrder, dataMode);
+			init_MightInline(clock, bitOrder, dataMode, dataSize);
 		}
 	}
-	SPISettings() { init_AlwaysInline(4000000, MSBFIRST, SPI_MODE0); }
+	SPISettings() { init_AlwaysInline(4000000, MSBFIRST, SPI_MODE0, DATA_SIZE_8BIT); }
 private:
-	void init_MightInline(uint32_t clock, BitOrder bitOrder, uint8_t dataMode) {
-		init_AlwaysInline(clock, bitOrder, dataMode);
+	void init_MightInline(uint32_t clock, BitOrder bitOrder, uint8_t dataMode, uint32_t dataSize) {
+		init_AlwaysInline(clock, bitOrder, dataMode, dataSize);
 	}
-	void init_AlwaysInline(uint32_t clock, BitOrder bitOrder, uint8_t dataMode) __attribute__((__always_inline__)) {
+	void init_AlwaysInline(uint32_t clock, BitOrder bitOrder, uint8_t dataMode, uint32_t dataSize) __attribute__((__always_inline__)) {
 		this->clock = clock;
 		this->bitOrder = bitOrder;
 		this->dataMode = dataMode;
+		this->dataSize = dataSize;
 	}
 	uint32_t clock;
 	BitOrder bitOrder;
 	uint8_t dataMode;
+	uint32_t dataSize;
 
 	spi_dev *spi_d;
 	uint8_t _SSPin;