SPI: added setBitOrder support; added end(pin) method.

Author: cmaglie

cores/arduino/wiring_constants.h

@@ -42,8 +42,10 @@ extern "C"{
 #define SERIAL  0x0
 #define DISPLAY 0x1
 
-#define LSBFIRST 0
-#define MSBFIRST 1
+enum BitOrder {
+	LSBFIRST = 0,
+	MSBFIRST = 1
+};
 
 #define CHANGE 1
 #define FALLING 2

libraries/SPI/SPI.cpp

@@ -25,6 +25,7 @@ void SPIClass::begin() {
 	// Default speed set to 4Mhz
 	setClockDivider(BOARD_SPI_DEFAULT_SS, 21);
 	setDataMode(BOARD_SPI_DEFAULT_SS, SPI_MODE0);
+	setBitOrder(BOARD_SPI_DEFAULT_SS, MSBFIRST);
 }
 
 void SPIClass::begin(uint8_t _pin) {
@@ -34,39 +35,50 @@ void SPIClass::begin(uint8_t _pin) {
 		g_APinDescription[spiPin].ulPinType,
 		g_APinDescription[spiPin].ulPin,
 		g_APinDescription[spiPin].ulPinConfiguration);
-	// Default speed set to 4Mhz
-	setClockDivider(_pin, 21);
+
+	// Default speed set to 500Khz
+	setClockDivider(_pin, 168);
 	setDataMode(_pin, SPI_MODE0);
+	setBitOrder(_pin, MSBFIRST);
+}
+
+void SPIClass::end(uint8_t _pin) {
+	uint32_t spiPin = BOARD_PIN_TO_SPI_PIN(_pin);
+	// Setting the pin as INPUT will disconnect it from SPI peripheral
+	pinMode(spiPin, INPUT);
 }
 
 void SPIClass::end() {
 	SPI_Disable(spi);
 }
 
-//void SPIClass::setBitOrder(uint8_t _bitOrder, uint8_t _channel) {
-//	// Not supported
-//}
+void SPIClass::setBitOrder(uint8_t _pin, BitOrder _bitOrder) {
+	uint32_t ch = BOARD_PIN_TO_SPI_CHANNEL(_pin);
+	bitOrder[ch] = _bitOrder;
+}
 
 void SPIClass::setDataMode(uint8_t _pin, uint8_t _mode) {
-	uint32_t _channel = BOARD_PIN_TO_SPI_CHANNEL(_pin);
-	mode[_channel] = _mode | SPI_CSR_CSAAT;
+	uint32_t ch = BOARD_PIN_TO_SPI_CHANNEL(_pin);
+	mode[ch] = _mode | SPI_CSR_CSAAT;
 	// SPI_CSR_DLYBCT(1) keeps CS enabled for 32 MCLK after a completed
 	// transfer. Some device needs that for working properly.
-	SPI_ConfigureNPCS(spi, _channel, mode[_channel] | SPI_CSR_SCBR(divider[_channel]) | SPI_CSR_DLYBCT(10) | (32<<16));
+	SPI_ConfigureNPCS(spi, ch, mode[ch] | SPI_CSR_SCBR(divider[ch]) | SPI_CSR_DLYBCT(1));
 }
 
 void SPIClass::setClockDivider(uint8_t _pin, uint8_t _divider) {
-	uint32_t _channel = BOARD_PIN_TO_SPI_CHANNEL(_pin);
-	divider[_channel] = _divider;
+	uint32_t ch = BOARD_PIN_TO_SPI_CHANNEL(_pin);
+	divider[ch] = _divider;
 	// SPI_CSR_DLYBCT(1) keeps CS enabled for 32 MCLK after a completed
 	// transfer. Some device needs that for working properly.
-//	SPI_ConfigureNPCS(spi, _channel, mode[_channel] | SPI_CSR_SCBR(divider[_channel]) | SPI_CSR_DLYBCT(1));
-	SPI_ConfigureNPCS(spi, _channel, mode[_channel] | SPI_CSR_SCBR(divider[_channel]) | SPI_CSR_DLYBCT(10) | (32<<16));
+	SPI_ConfigureNPCS(spi, ch, mode[ch] | SPI_CSR_SCBR(divider[ch]) | SPI_CSR_DLYBCT(1));
 }
 
 byte SPIClass::transfer(byte _pin, uint8_t _data, SPITransferMode _mode) {
-	uint32_t _channel = BOARD_PIN_TO_SPI_CHANNEL(_pin);
-	uint32_t d = _data | SPI_PCS(_channel);
+	uint32_t ch = BOARD_PIN_TO_SPI_CHANNEL(_pin);
+	// Reverse bit order
+	if (bitOrder[ch] == LSBFIRST)
+		_data = __REV(__RBIT(_data));
+	uint32_t d = _data | SPI_PCS(ch);
 	if (_mode == SPI_LAST)
 		d |= SPI_TDR_LASTXFER;
 
@@ -79,6 +91,9 @@ byte SPIClass::transfer(byte _pin, uint8_t _data, SPITransferMode _mode) {
     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;
 }
 

libraries/SPI/SPI.h

@@ -36,23 +36,27 @@ class SPIClass {
 	void attachInterrupt(void);
 	void detachInterrupt(void);
 
-	void begin(uint8_t _channel);
 	void begin(void);
 	void end(void);
 
+	// Attach/Detach pin to/from SPI controller
+	void begin(uint8_t _pin);
+	void end(uint8_t _pin);
+
 	// These methods sets a parameter on a single pin
-	//void setBitOrder(uint8_t _channel, uint8_t);
-	void setDataMode(uint8_t _channel, uint8_t);
-	void setClockDivider(uint8_t _channel, uint8_t);
+	void setBitOrder(uint8_t _pin, BitOrder);
+	void setDataMode(uint8_t _pin, uint8_t);
+	void setClockDivider(uint8_t _pin, uint8_t);
 
-	// These methods sets the same parameters but on default pin PIN_SPI_SS_DEFAULT
-	//void setBitOrder(uint8_t _order) { setBitOrder(PIN_SPI_SS_DEFAULT, _order); };
+	// These methods sets the same parameters but on default pin BOARD_SPI_DEFAULT_SS
+	void setBitOrder(BitOrder _order) { setBitOrder(BOARD_SPI_DEFAULT_SS, _order); };
 	void setDataMode(uint8_t _mode) { setDataMode(BOARD_SPI_DEFAULT_SS, _mode); };
 	void setClockDivider(uint8_t _div) { setClockDivider(BOARD_SPI_DEFAULT_SS, _div); };
 
   private:
 	Spi *spi;
 	uint32_t id;
+	BitOrder bitOrder[SPI_CHANNELS_NUM];
 	uint32_t divider[SPI_CHANNELS_NUM];
 	uint32_t mode[SPI_CHANNELS_NUM];
 	void (*initCb)(void);