Patch, SPI.transfer16()

Implement SPI.transfer16() as a true 16 bit transfer

Signed-off-by: Dr M <[email protected]>

Author: drmcnelson

libraries/SPI/src/SPI.cpp

@@ -176,7 +176,7 @@ uint8_t SPIClass::transfer(uint8_t data, bool skipReceive)
   *         Optional, default: SPI_TRANSMITRECEIVE.
   * @return bytes received from the slave in 16 bits format.
   */
-uint16_t SPIClass::transfer16(uint16_t data, bool skipReceive)
+uint16_t SPIClass::transfer16_obsoleted(uint16_t data, bool skipReceive)
 {
   uint16_t tmp;
 
@@ -194,6 +194,26 @@ uint16_t SPIClass::transfer16(uint16_t data, bool skipReceive)
   return data;
 }
 
+uint16_t SPIClass::transfer16(uint16_t data, bool skipReceive)
+{
+  uint16_t tmp;
+  uint16_t out;
+
+  if (_spiSettings.bitOrder) {
+    tmp = ((data & 0xff00) >> 8) | ((data & 0xff) << 8);
+    data = tmp;
+  }
+  
+  spi_transfer16(&_spi, (uint16_t *)&data, (!skipReceive) ? (uint16_t *)&out : NULL);
+
+  if (_spiSettings.bitOrder) {
+    tmp = ((out & 0xff00) >> 8) | ((out & 0xff) << 8);
+    out = tmp;
+  }
+
+  return out;
+}
+
 /**
   * @brief  Transfer several bytes. Only one buffer used to send and receive data.
   *         begin() or beginTransaction() must be called at least once before.

libraries/SPI/src/SPI.h

@@ -136,6 +136,7 @@ class SPIClass {
      */
     uint8_t transfer(uint8_t data, bool skipReceive = SPI_TRANSMITRECEIVE);
     uint16_t transfer16(uint16_t data, bool skipReceive = SPI_TRANSMITRECEIVE);
+    uint16_t transfer16_obsoleted(uint16_t data, bool skipReceive = SPI_TRANSMITRECEIVE);
     void transfer(void *buf, size_t count, bool skipReceive = SPI_TRANSMITRECEIVE);
 
     /* Expand SPI API

libraries/SPI/src/utility/spi_com.c

@@ -30,8 +30,7 @@ uint32_t spi_getClkFreqInst(SPI_TypeDef *spi_inst)
 {
   uint32_t spi_freq = SystemCoreClock;
   if (spi_inst != NP) {
-#if defined(STM32C0xx) || defined(STM32F0xx) || defined(STM32G0xx) || \
-    defined(STM32U0xx)
+#if defined(STM32C0xx) || defined(STM32F0xx) || defined(STM32G0xx)
     /* SPIx source CLK is PCKL1 */
     spi_freq = HAL_RCC_GetPCLK1Freq();
 #else
@@ -544,6 +543,67 @@ spi_status_e spi_transfer(spi_t *obj, const uint8_t *tx_buffer, uint8_t *rx_buff
   return ret;
 }
 
+spi_status_e spi_transfer16(spi_t *obj, const uint16_t *tx_buffer, uint16_t *rx_buffer)
+{
+  spi_status_e ret = SPI_OK;
+  uint32_t tickstart;
+  SPI_TypeDef *_SPI = obj->handle.Instance;
+  uint16_t *tx_buf = (uint16_t *)tx_buffer;
+
+  tickstart = HAL_GetTick();
+
+#if defined(SPI_CR2_TSIZE)
+  /* Start transfer */
+  LL_SPI_SetTransferSize(_SPI, 1);
+  LL_SPI_Enable(_SPI);
+  LL_SPI_StartMasterTransfer(_SPI);
+#endif
+
+#if defined(SPI_SR_TXP)
+  while (!LL_SPI_IsActiveFlag_TXP(_SPI));
+#else
+  while (!LL_SPI_IsActiveFlag_TXE(_SPI));
+#endif
+
+  LL_SPI_TransmitData16(_SPI, tx_buf ? *tx_buf : 0XFF);
+
+#if defined(SPI_SR_RXP)
+  while (!LL_SPI_IsActiveFlag_RXP(_SPI));
+#else
+  while (!LL_SPI_IsActiveFlag_RXNE(_SPI));
+#endif
+
+  if (rx_buffer) {
+    *rx_buffer = LL_SPI_ReceiveData16(_SPI);
+  } else {
+    LL_SPI_ReceiveData16(_SPI);
+  }
+
+  if ((SPI_TRANSFER_TIMEOUT != HAL_MAX_DELAY) &&
+      (HAL_GetTick() - tickstart >= SPI_TRANSFER_TIMEOUT)) {
+    ret = SPI_TIMEOUT;
+  }
+
+#if defined(SPI_IFCR_EOTC)
+  // Add a delay before disabling SPI otherwise last-bit/last-clock may be truncated
+  // See https://github.com/stm32duino/Arduino_Core_STM32/issues/1294
+  // Computed delay is half SPI clock
+  delayMicroseconds(obj->disable_delay);
+
+  /* Close transfer */
+  /* Clear flags */
+  LL_SPI_ClearFlag_EOT(_SPI);
+  LL_SPI_ClearFlag_TXTF(_SPI);
+  /* Disable SPI peripheral */
+  LL_SPI_Disable(_SPI);
+#else
+  /* Wait for end of transfer */
+  while (LL_SPI_IsActiveFlag_BSY(_SPI));
+#endif
+  
+  return ret;
+}
+
 #ifdef __cplusplus
 }
 #endif

libraries/SPI/src/utility/spi_com.h

@@ -85,6 +85,7 @@ typedef enum {
 void spi_init(spi_t *obj, uint32_t speed, SPIMode mode, uint8_t msb);
 void spi_deinit(spi_t *obj);
 spi_status_e spi_transfer(spi_t *obj, const uint8_t *tx_buffer, uint8_t *rx_buffer, uint16_t len);
+spi_status_e spi_transfer16(spi_t *obj, const uint16_t *tx_buffer, uint16_t *rx_buffer);
 uint32_t spi_getClkFreq(spi_t *obj);
 
 #ifdef __cplusplus