1 files changed, 16 insertions, 8 deletions
diff --git a/os/io/platforms/STM32/spi_lld.c b/os/io/platforms/STM32/spi_lld.c
index 934501cf6..8cd7ba8e1 100644
--- a/os/io/platforms/STM32/spi_lld.c
+++ b/os/io/platforms/STM32/spi_lld.c
@@ -301,9 +301,13 @@ void spi_lld_unselect(SPIDriver *spip) {
  * @details This function performs a simultaneous transmit/receive operation.
  *
  * @param[in] spip pointer to the @p SPIDriver object
- * @param n number of words to exchange
- * @param rxbuf the pointer to the receive buffer
- * @param txbuf the pointer to the transmit buffer
+ * @param[in] n number of words to exchange
+ * @param[in] txbuf the pointer to the transmit buffer. Note that the buffer is
+ *                  organized as an uint8_t array for data sizes below or equal
+ *                  to 8 bits else it is organized as an uint16_t array.
+ * @param[out] rxbuf the pointer to the receive buffer. Note that the buffer is
+ *                   organized as an uint8_t array for data sizes below or equal
+ *                   to 8 bits else it is organized as an uint16_t array.
  * @return The operation status is returned.
  * @retval RDY_OK operation complete.
  * @retval RDY_RESET hardware failure.
@@ -311,7 +315,7 @@ void spi_lld_unselect(SPIDriver *spip) {
  * @note The buffers are organized as uint8_t arrays for data sizes below or
  *       equal to 8 bits else it is organized as uint16_t arrays.
  */
-msg_t spi_lld_exchange(SPIDriver *spip, size_t n, void *rxbuf, void *txbuf) {
+msg_t spi_lld_exchange(SPIDriver *spip, size_t n, void *txbuf, void *rxbuf) {
 
   spip->spd_dmarx->CCR = DMA_CCR1_TCIE | DMA_CCR1_MINC | DMA_CCR1_TEIE;
   spip->spd_dmatx->CCR = DMA_CCR1_DIR  | DMA_CCR1_MINC | DMA_CCR1_TEIE;
@@ -323,8 +327,10 @@ msg_t spi_lld_exchange(SPIDriver *spip, size_t n, void *rxbuf, void *txbuf) {
  * @brief Sends data ever the SPI bus.
  *
  * @param[in] spip pointer to the @p SPIDriver object
- * @param n number of words to send
- * @param txbuf the pointer to the transmit buffer
+ * @param[in] n number of words to send
+ * @param[in] txbuf the pointer to the transmit buffer. Note that the buffer is
+ *                  organized as an uint8_t array for data sizes below or equal
+ *                  to 8 bits else it is organized as an uint16_t array.
  * @return The operation status is returned.
  * @retval RDY_OK operation complete.
  * @retval RDY_RESET hardware failure.
@@ -344,8 +350,10 @@ msg_t spi_lld_send(SPIDriver *spip, size_t n, void *txbuf) {
  * @brief Receives data from the SPI bus.
  *
  * @param[in] spip pointer to the @p SPIDriver object
- * @param n number of words to receive
- * @param rxbuf the pointer to the receive buffer
+ * @param[in] n number of words to receive
+ * @param[out] rxbuf the pointer to the receive buffer. Note that the buffer is
+ *                   organized as an uint8_t array for data sizes below or equal
+ *                   to 8 bits else it is organized as an uint16_t array.
  * @return The operation status is returned.
  * @retval RDY_OK operation complete.
  * @retval RDY_RESET hardware failure.