further optimizations

- extend read function to 16bit
- add repeated write the same byte/word a specified number of time
- revert increment option to dmaSend

Author: stevstrong

STM32F1/cores/maple/libmaple/spi.c

@@ -93,16 +93,21 @@ void spi_slave_enable(spi_dev *dev, spi_mode mode, uint32 flags) {
  * @return Number of elements transmitted.
  */
 uint32 spi_tx(spi_dev *dev, const void *buf, uint32 len) {
-    uint32 txed = 0;
-    uint8 byte_frame = spi_dff(dev) == SPI_DFF_8_BIT;
-    while ( txed < len ) {
-		while ( spi_is_tx_empty(dev)==0 ); // wait Tx to be empty
-        if (byte_frame) {
-            dev->regs->DR = ((const uint8*)buf)[txed++];
-        } else {
-            dev->regs->DR = ((const uint16*)buf)[txed++];
-        }
-    }
+    uint32 txed = len;
+	spi_reg_map *regs = dev->regs;
+    if ( spi_dff(dev) == SPI_DFF_8_BIT ) {
+		const uint8 * dp8 = (const uint8*)buf;
+		while ( len-- ) {
+			while ( (regs->SR & SPI_SR_TXE)==0 ) ; //while ( spi_is_tx_empty(dev)==0 ); // wait Tx to be empty
+			regs->DR = *dp8++;
+		}
+    } else {
+		const uint16 * dp16 = (const uint16*)buf;
+		while ( len-- ) {
+			while ( (regs->SR & SPI_SR_TXE)==0 ) ; //while ( spi_is_tx_empty(dev)==0 ); // wait Tx to be empty
+			regs->DR = *dp16++;
+		}
+	}
     return txed;
 }
 
@@ -163,6 +168,5 @@ static void spi_reconfigure(spi_dev *dev, uint32 cr1_config) {
 	spi_irq_disable(dev, SPI_INTERRUPTS_ALL);
 	if ( (dev->regs->CR1&MASK)!=(cr1_config&MASK) )	spi_peripheral_disable(dev);
 	dev->regs->CR1 = cr1_config;
-	//spi_rx_dma_enable(dev);
 	spi_peripheral_enable(dev);
 }

STM32F1/libraries/SPI/src/SPI.cpp

@@ -160,7 +160,7 @@ void SPIClass::begin(void) {
 void SPIClass::beginSlave(void) {
     spi_init(_currentSetting->spi_d);
     configure_gpios(_currentSetting->spi_d, 0);
-    uint32 flags = ((_currentSetting->bitOrder == MSBFIRST ? SPI_FRAME_MSB : SPI_FRAME_LSB) | _currentSetting->dataSize | SPI_SW_SLAVE);
+    uint32 flags = ((_currentSetting->bitOrder == MSBFIRST ? SPI_FRAME_MSB : SPI_FRAME_LSB) | _currentSetting->dataSize | SPI_RX_ONLY);
 	#ifdef SPI_DEBUG
 	Serial.print("spi_slave_enable("); Serial.print(_currentSetting->dataMode); Serial.print(","); Serial.print(flags); Serial.println(")");
 	#endif
@@ -306,10 +306,10 @@ void SPIClass::endTransaction(void)
  * I/O
  */
 
-uint8 SPIClass::read(void)
+uint16 SPIClass::read(void)
 {
 	while ( spi_is_rx_nonempty(_currentSetting->spi_d)==0 ) ;
-	return (uint8)spi_rx_reg(_currentSetting->spi_d);
+	return (uint16)spi_rx_reg(_currentSetting->spi_d);
 }
 
 void SPIClass::read(uint8 *buf, uint32 len)
@@ -321,7 +321,7 @@ void SPIClass::read(uint8 *buf, uint32 len)
     while ( rxed < len) {
 		regs->DR = 0x00FF; // " write the data item to be transmitted into the SPI_DR register (this clears the TXE flag)."
         while ( (regs->SR & SPI_SR_RXNE)==0 ) ; // wait till data is available in the Rx register
-        buf[rxed++] = (uint8)(regs->DR); // read and store the received byte
+        *buf++ = (regs->DR); // read and store the received byte
     }
 }
 
@@ -332,11 +332,21 @@ void SPIClass::write(uint16 data)
 	 * by taking the Tx code from transfer(byte)
 	 * This almost doubles the speed of this function.
 	 */
-	spi_tx_reg(_currentSetting->spi_d, data); // "2. Write the first data item to be transmitted into the SPI_DR register (this clears the TXE flag)."
-	while (spi_is_tx_empty(_currentSetting->spi_d) == 0); // "5. Wait until TXE=1 ..."
+	spi_tx_reg(_currentSetting->spi_d, data); // write the data to be transmitted into the SPI_DR register (this clears the TXE flag)
 	while (spi_is_busy(_currentSetting->spi_d) != 0); // "... and then wait until BSY=0 before disabling the SPI." 
 }
 
+void SPIClass::write(uint16 data, uint32 n)
+{
+	// Added by stevstrong: Repeatedly send same data by the specified number of times
+	spi_reg_map * regs = _currentSetting->spi_d->regs;
+	while ( (n--)>0 ) {
+		regs->DR = data; // write the data to be transmitted into the SPI_DR register (this clears the TXE flag)
+        while ( (regs->SR & SPI_SR_TXE)==0 ) ; // wait till Tx empty
+	}
+	while ( (regs->SR & SPI_SR_BSY) != 0); // wait until BSY=0 before returning 
+}
+
 void SPIClass::write(const void *data, uint32 length)
 {
     spi_tx(_currentSetting->spi_d, data, length); // data can be array of bytes or words
@@ -346,18 +356,18 @@ void SPIClass::write(const void *data, uint32 length)
 	uint16 b = spi_rx_reg(_currentSetting->spi_d); // dummy read, needed, don't remove!
 }
 
-uint16_t SPIClass::transfer16(uint16_t wr_data) const {
-	spi_tx_reg(_currentSetting->spi_d, wr_data); // "2. Write the first data item to be transmitted into the SPI_DR register (this clears the TXE flag)."
+uint8 SPIClass::transfer(uint8 byte) const {
+	spi_tx_reg(_currentSetting->spi_d, byte); // "2. Write the first data item to be transmitted into the SPI_DR register (this clears the TXE flag)."
 	while (spi_is_tx_empty(_currentSetting->spi_d) == 0); // "5. Wait until TXE=1 ..."
 	while (spi_is_busy(_currentSetting->spi_d) != 0); // "... and then wait until BSY=0 before disabling the SPI."
-	return (uint16)spi_rx_reg(_currentSetting->spi_d); // "... and read the last received data."
+	return (uint8)spi_rx_reg(_currentSetting->spi_d); // "... and read the last received data."
 }
 
-uint8 SPIClass::transfer(uint8 byte) const {
-	spi_tx_reg(_currentSetting->spi_d, byte); // "2. Write the first data item to be transmitted into the SPI_DR register (this clears the TXE flag)."
+uint16_t SPIClass::transfer16(uint16_t wr_data) const {
+	spi_tx_reg(_currentSetting->spi_d, wr_data); // "2. Write the first data item to be transmitted into the SPI_DR register (this clears the TXE flag)."
 	while (spi_is_tx_empty(_currentSetting->spi_d) == 0); // "5. Wait until TXE=1 ..."
 	while (spi_is_busy(_currentSetting->spi_d) != 0); // "... and then wait until BSY=0 before disabling the SPI."
-	return (uint8)spi_rx_reg(_currentSetting->spi_d); // "... and read the last received data."
+	return (uint16)spi_rx_reg(_currentSetting->spi_d); // "... and read the last received data."
 }
 
 /*  Roger Clark and Victor Perez, 2015
@@ -419,10 +429,10 @@ uint8 SPIClass::dmaTransfer(void * transmitBuf, void * receiveBuf, uint16 length
 *	Still in progress.
 *	2016 - stevstrong - reworked to automatically detect bit size from SPI setting
 */
-uint8 SPIClass::dmaSend(void * transmitBuf, uint16 length)
+uint8 SPIClass::dmaSend(void * transmitBuf, uint16 length, bool minc)
 {
 	if (length == 0) return 0;
-	uint32 flags = (DMA_MINC_MODE | DMA_FROM_MEM | DMA_TRNS_CMPLT);
+	uint32 flags = ( (DMA_MINC_MODE*minc) | DMA_FROM_MEM | DMA_TRNS_CMPLT);
 	uint8 b = 0;
 //	dma1_ch3_Active=true;
     dma_init(_currentSetting->spiDmaDev);
@@ -438,7 +448,7 @@ uint8 SPIClass::dmaSend(void * transmitBuf, uint16 length)
 
 //    while (dma1_ch3_Active);
     uint32_t m = millis();
-	while ((dma_get_isr_bits(_currentSetting->spiDmaDev, _currentSetting->spiTxDmaChannel) & 0x2)==0) {//Avoid interrupts and just loop waiting for the flag to be set.
+	while ((dma_get_isr_bits(_currentSetting->spiDmaDev, _currentSetting->spiTxDmaChannel) & DMA_ISR_TCIF1)==0) {//Avoid interrupts and just loop waiting for the flag to be set.
 		if ((millis() - m) > DMA_TIMEOUT) { b = 2; break; }
     }
 	dma_clear_isr_bits(_currentSetting->spiDmaDev, _currentSetting->spiTxDmaChannel);

STM32F1/libraries/SPI/src/SPI.h

@@ -115,6 +115,13 @@ class SPISettings {
 			init_MightInline(clock, bitOrder, dataMode, dataSize);
 		}
 	}
+	SPISettings(uint32_t clock) {
+		if (__builtin_constant_p(clock)) {
+			init_AlwaysInline(clock, MSBFIRST, SPI_MODE0, DATA_SIZE_8BIT);
+		} else {
+			init_MightInline(clock, MSBFIRST, SPI_MODE0, DATA_SIZE_8BIT);
+		}
+	}
 	SPISettings() { init_AlwaysInline(4000000, MSBFIRST, SPI_MODE0, DATA_SIZE_8BIT); }
 private:
 	void init_MightInline(uint32_t clock, BitOrder bitOrder, uint8_t dataMode, uint32_t dataSize) {
@@ -216,38 +223,38 @@ class SPIClass {
      */
 
     /**
-     * @brief Return the next unread byte.
+     * @brief Return the next unread byte/word.
      *
-     * If there is no unread byte waiting, this function will block
+     * If there is no unread byte/word waiting, this function will block
      * until one is received.
      */
-    uint8 read(void);
+    uint16 read(void);
 
     /**
      * @brief Read length bytes, storing them into buffer.
      * @param buffer Buffer to store received bytes into.
-     * @param length Number of bytes to store in buffer.  This
+     * @param length Number of bytes to store in buffer. This
      *               function will block until the desired number of
      *               bytes have been read.
      */
     void read(uint8 *buffer, uint32 length);
 
     /**
-     * @brief Transmit a byte.
-     * @param data Byte to transmit.
+     * @brief Transmit one byte/word.
+     * @param data to transmit.
      */
-//    void write(uint8 data);
-
+    void write(uint16 data);	
+	
     /**
-     * @brief Transmit a half word.
+     * @brief Transmit one byte/word a specified number of times.
      * @param data to transmit.
      */
-    void write(uint16 data);	
+    void write(uint16 data, uint32 n);	
 
     /**
-     * @brief Transmit multiple bytes.
-     * @param buffer Bytes to transmit.
-     * @param length Number of bytes in buffer to transmit.
+     * @brief Transmit multiple bytes/words.
+     * @param buffer Bytes/words to transmit.
+     * @param length Number of bytes/words in buffer to transmit.
      */
     void write(const void * buffer, uint32 length);
 
@@ -283,7 +290,7 @@ class SPIClass {
      * @param data buffer half words to transmit,
      * @param length Number of bytes in buffer to transmit.
      */
-	uint8 dmaSend(void * transmitBuf, uint16 length);
+	uint8 dmaSend(void * transmitBuf, uint16 length, bool minc = 1);
 
     /*
      * Pin accessors