diff options
Diffstat (limited to 'os/hal/platforms/LPC17xx/spi_lld.c')
| -rw-r--r-- | os/hal/platforms/LPC17xx/spi_lld.c | 774 |
1 files changed, 387 insertions, 387 deletions
diff --git a/os/hal/platforms/LPC17xx/spi_lld.c b/os/hal/platforms/LPC17xx/spi_lld.c index 483739aba..a388361f1 100644 --- a/os/hal/platforms/LPC17xx/spi_lld.c +++ b/os/hal/platforms/LPC17xx/spi_lld.c @@ -1,387 +1,387 @@ -/* - ChibiOS/RT - Copyright (C) 2006-2013 Giovanni Di Sirio - - Licensed under the Apache License, Version 2.0 (the "License"); - you may not use this file except in compliance with the License. - You may obtain a copy of the License at - - http://www.apache.org/licenses/LICENSE-2.0 - - Unless required by applicable law or agreed to in writing, software - distributed under the License is distributed on an "AS IS" BASIS, - WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - See the License for the specific language governing permissions and - limitations under the License. -*/ - -/** - * @file LPC17xx/spi_lld.c - * @brief LPC17xx low level SPI driver code. - * - * @addtogroup SPI - * @{ - */ - -#include "ch.h" -#include "hal.h" - -#if HAL_USE_SPI || defined(__DOXYGEN__) - -/*===========================================================================*/ -/* Driver exported variables. */ -/*===========================================================================*/ - -#if LPC17xx_SPI_USE_SSP0 || defined(__DOXYGEN__) -/** @brief SPI1 driver identifier.*/ -SPIDriver SPID1; -#endif - -#if LPC17xx_SPI_USE_SSP1 || defined(__DOXYGEN__) -/** @brief SPI2 driver identifier.*/ -SPIDriver SPID2; -#endif - -/*===========================================================================*/ -/* Driver local variables and types. */ -/*===========================================================================*/ - -/*===========================================================================*/ -/* Driver local functions. */ -/*===========================================================================*/ - -/** - * @brief Preloads the transmit FIFO. - * - * @param[in] spip pointer to the @p SPIDriver object - */ -static void ssp_fifo_preload(SPIDriver *spip) { - LPC_SSP_TypeDef *ssp = spip->ssp; - uint32_t n = spip->txcnt > LPC17xx_SSP_FIFO_DEPTH ? - LPC17xx_SSP_FIFO_DEPTH : spip->txcnt; - - while(((ssp->SR & SR_TNF) != 0) && (n > 0)) { - if (spip->txptr != NULL) { - if ((ssp->CR0 & CR0_DSSMASK) > CR0_DSS8BIT) { - const uint16_t *p = spip->txptr; - ssp->DR = *p++; - spip->txptr = p; - } - else { - const uint8_t *p = spip->txptr; - ssp->DR = *p++; - spip->txptr = p; - } - } - else - ssp->DR = 0xFFFFFFFF; - n--; - spip->txcnt--; - } -} - -/** - * @brief Common IRQ handler. - * - * @param[in] spip pointer to the @p SPIDriver object - */ -static void spi_serve_interrupt(SPIDriver *spip) { - LPC_SSP_TypeDef *ssp = spip->ssp; - - if ((ssp->MIS & MIS_ROR) != 0) { - /* The overflow condition should never happen because priority is given - to receive but a hook macro is provided anyway...*/ - LPC17xx_SPI_SSP_ERROR_HOOK(spip); - } - ssp->ICR = ICR_RT | ICR_ROR; - while ((ssp->SR & SR_RNE) != 0) { - if (spip->rxptr != NULL) { - if ((ssp->CR0 & CR0_DSSMASK) > CR0_DSS8BIT) { - uint16_t *p = spip->rxptr; - *p++ = ssp->DR; - spip->rxptr = p; - } - else { - uint8_t *p = spip->rxptr; - *p++ = ssp->DR; - spip->rxptr = p; - } - } - else - (void)ssp->DR; - if (--spip->rxcnt == 0) { - chDbgAssert(spip->txcnt == 0, - "spi_serve_interrupt(), #1", "counter out of synch"); - /* Stops the IRQ sources.*/ - ssp->IMSC = 0; - /* Portable SPI ISR code defined in the high level driver, note, it is - a macro.*/ - _spi_isr_code(spip); - return; - } - } - ssp_fifo_preload(spip); - if (spip->txcnt == 0) - ssp->IMSC = IMSC_ROR | IMSC_RT | IMSC_RX; -} - -/*===========================================================================*/ -/* Driver interrupt handlers. */ -/*===========================================================================*/ - -#if LPC17xx_SPI_USE_SSP0 || defined(__DOXYGEN__) -/** - * @brief SSP0 interrupt handler. - * - * @isr - */ -CH_IRQ_HANDLER(Vector78) { - - CH_IRQ_PROLOGUE(); - - spi_serve_interrupt(&SPID1); - - CH_IRQ_EPILOGUE(); -} -#endif - -#if LPC17xx_SPI_USE_SSP1 || defined(__DOXYGEN__) -/** - * @brief SSP1 interrupt handler. - * - * @isr - */ -CH_IRQ_HANDLER(Vector7C) { - - CH_IRQ_PROLOGUE(); - - spi_serve_interrupt(&SPID2); - - CH_IRQ_EPILOGUE(); -} -#endif - -/*===========================================================================*/ -/* Driver exported functions. */ -/*===========================================================================*/ - -/** - * @brief Low level SPI driver initialization. - * - * @notapi - */ -void spi_lld_init(void) { - -#if LPC17xx_SPI_USE_SSP0 - spiObjectInit(&SPID1); - SPID1.ssp = LPC_SSP0; -#endif /* LPC17xx_SPI_USE_SSP0 */ - -#if LPC17xx_SPI_USE_SSP1 - spiObjectInit(&SPID2); - SPID2.ssp = LPC_SSP1; -#endif /* LPC17xx_SPI_USE_SSP0 */ -} - -/** - * @brief Configures and activates the SPI peripheral. - * - * @param[in] spip pointer to the @p SPIDriver object - * - * @notapi - */ -void spi_lld_start(SPIDriver *spip) { - - if (spip->state == SPI_STOP) { - /* Clock activation.*/ -#if LPC17xx_SPI_USE_SSP0 - if (&SPID1 == spip) { - LPC_SC->PCONP |= (1UL << 21); - LPC_SC->PCLKSEL0 &= (PCLKSEL_MASK << 20); - LPC_SC->PCLKSEL0 |= (LPC17xx_SPI_SSP0_PCLKSEL << 20); - nvicEnableVector(SSP0_IRQn, - CORTEX_PRIORITY_MASK(LPC17xx_SPI_SSP0_IRQ_PRIORITY)); - } -#endif -#if LPC17xx_SPI_USE_SSP1 - if (&SPID2 == spip) { - LPC_SC->PCONP |= (1UL << 10); - LPC_SC->PCLKSEL1 &= (PCLKSEL_MASK << 10); - LPC_SC->PCLKSEL1 |= (LPC17xx_SPI_SSP0_PCLKSEL << 10); - nvicEnableVector(SSP1_IRQn, - CORTEX_PRIORITY_MASK(LPC17xx_SPI_SSP1_IRQ_PRIORITY)); - } -#endif - } - /* Configuration.*/ - spip->ssp->CR1 = 0; - spip->ssp->ICR = ICR_RT | ICR_ROR; - spip->ssp->CR0 = spip->config->cr0; - spip->ssp->CPSR = spip->config->cpsr; - spip->ssp->CR1 = CR1_SSE; -} - -/** - * @brief Deactivates the SPI peripheral. - * - * @param[in] spip pointer to the @p SPIDriver object - * - * @notapi - */ -void spi_lld_stop(SPIDriver *spip) { - - if (spip->state != SPI_STOP) { - spip->ssp->CR1 = 0; - spip->ssp->CR0 = 0; - spip->ssp->CPSR = 0; -#if LPC17xx_SPI_USE_SSP0 - if (&SPID1 == spip) { - LPC_SC->PCONP &= ~(1UL << 21); - nvicDisableVector(SSP0_IRQn); - } -#endif -#if LPC17xx_SPI_USE_SSP1 - if (&SPID2 == spip) { - LPC_SC->PCONP &= ~(1UL << 10); - nvicDisableVector(SSP1_IRQn); - } -#endif - } -} - -/** - * @brief Asserts the slave select signal and prepares for transfers. - * - * @param[in] spip pointer to the @p SPIDriver object - * - * @notapi - */ -void spi_lld_select(SPIDriver *spip) { - - palClearPad(spip->config->ssport, spip->config->sspad); -} - -/** - * @brief Deasserts the slave select signal. - * @details The previously selected peripheral is unselected. - * - * @param[in] spip pointer to the @p SPIDriver object - * - * @notapi - */ -void spi_lld_unselect(SPIDriver *spip) { - - palSetPad(spip->config->ssport, spip->config->sspad); -} - -/** - * @brief Ignores data on the SPI bus. - * @details This function transmits a series of idle words on the SPI bus and - * ignores the received data. This function can be invoked even - * when a slave select signal has not been yet asserted. - * - * @param[in] spip pointer to the @p SPIDriver object - * @param[in] n number of words to be ignored - * - * @notapi - */ -void spi_lld_ignore(SPIDriver *spip, size_t n) { - - spip->rxptr = NULL; - spip->txptr = NULL; - spip->rxcnt = spip->txcnt = n; - ssp_fifo_preload(spip); - spip->ssp->IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX; -} - -/** - * @brief Exchanges data on the SPI bus. - * @details This asynchronous function starts a simultaneous transmit/receive - * operation. - * @post At the end of the operation the configured callback is invoked. - * @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. - * - * @param[in] spip pointer to the @p SPIDriver object - * @param[in] n number of words to be exchanged - * @param[in] txbuf the pointer to the transmit buffer - * @param[out] rxbuf the pointer to the receive buffer - * - * @notapi - */ -void spi_lld_exchange(SPIDriver *spip, size_t n, - const void *txbuf, void *rxbuf) { - - spip->rxptr = rxbuf; - spip->txptr = txbuf; - spip->rxcnt = spip->txcnt = n; - ssp_fifo_preload(spip); - spip->ssp->IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX; -} - -/** - * @brief Sends data over the SPI bus. - * @details This asynchronous function starts a transmit operation. - * @post At the end of the operation the configured callback is invoked. - * @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. - * - * @param[in] spip pointer to the @p SPIDriver object - * @param[in] n number of words to send - * @param[in] txbuf the pointer to the transmit buffer - * - * @notapi - */ -void spi_lld_send(SPIDriver *spip, size_t n, const void *txbuf) { - - spip->rxptr = NULL; - spip->txptr = txbuf; - spip->rxcnt = spip->txcnt = n; - ssp_fifo_preload(spip); - spip->ssp->IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX; -} - -/** - * @brief Receives data from the SPI bus. - * @details This asynchronous function starts a receive operation. - * @post At the end of the operation the configured callback is invoked. - * @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. - * - * @param[in] spip pointer to the @p SPIDriver object - * @param[in] n number of words to receive - * @param[out] rxbuf the pointer to the receive buffer - * - * @notapi - */ -void spi_lld_receive(SPIDriver *spip, size_t n, void *rxbuf) { - - spip->rxptr = rxbuf; - spip->txptr = NULL; - spip->rxcnt = spip->txcnt = n; - ssp_fifo_preload(spip); - spip->ssp->IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX; -} - -/** - * @brief Exchanges one frame using a polled wait. - * @details This synchronous function exchanges one frame using a polled - * synchronization method. This function is useful when exchanging - * small amount of data on high speed channels, usually in this - * situation is much more efficient just wait for completion using - * polling than suspending the thread waiting for an interrupt. - * - * @param[in] spip pointer to the @p SPIDriver object - * @param[in] frame the data frame to send over the SPI bus - * @return The received data frame from the SPI bus. - */ -uint16_t spi_lld_polled_exchange(SPIDriver *spip, uint16_t frame) { - - spip->ssp->DR = (uint32_t)frame; - while ((spip->ssp->SR & SR_RNE) == 0) - ; - return (uint16_t)spip->ssp->DR; -} - -#endif /* HAL_USE_SPI */ - -/** @} */ +/*
+ ChibiOS/RT - Copyright (C) 2006-2013 Giovanni Di Sirio
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+*/
+
+/**
+ * @file LPC17xx/spi_lld.c
+ * @brief LPC17xx low level SPI driver code.
+ *
+ * @addtogroup SPI
+ * @{
+ */
+
+#include "ch.h"
+#include "hal.h"
+
+#if HAL_USE_SPI || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Driver exported variables. */
+/*===========================================================================*/
+
+#if LPC17xx_SPI_USE_SSP0 || defined(__DOXYGEN__)
+/** @brief SPI1 driver identifier.*/
+SPIDriver SPID1;
+#endif
+
+#if LPC17xx_SPI_USE_SSP1 || defined(__DOXYGEN__)
+/** @brief SPI2 driver identifier.*/
+SPIDriver SPID2;
+#endif
+
+/*===========================================================================*/
+/* Driver local variables and types. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver local functions. */
+/*===========================================================================*/
+
+/**
+ * @brief Preloads the transmit FIFO.
+ *
+ * @param[in] spip pointer to the @p SPIDriver object
+ */
+static void ssp_fifo_preload(SPIDriver *spip) {
+ LPC_SSP_TypeDef *ssp = spip->ssp;
+ uint32_t n = spip->txcnt > LPC17xx_SSP_FIFO_DEPTH ?
+ LPC17xx_SSP_FIFO_DEPTH : spip->txcnt;
+
+ while(((ssp->SR & SR_TNF) != 0) && (n > 0)) {
+ if (spip->txptr != NULL) {
+ if ((ssp->CR0 & CR0_DSSMASK) > CR0_DSS8BIT) {
+ const uint16_t *p = spip->txptr;
+ ssp->DR = *p++;
+ spip->txptr = p;
+ }
+ else {
+ const uint8_t *p = spip->txptr;
+ ssp->DR = *p++;
+ spip->txptr = p;
+ }
+ }
+ else
+ ssp->DR = 0xFFFFFFFF;
+ n--;
+ spip->txcnt--;
+ }
+}
+
+/**
+ * @brief Common IRQ handler.
+ *
+ * @param[in] spip pointer to the @p SPIDriver object
+ */
+static void spi_serve_interrupt(SPIDriver *spip) {
+ LPC_SSP_TypeDef *ssp = spip->ssp;
+
+ if ((ssp->MIS & MIS_ROR) != 0) {
+ /* The overflow condition should never happen because priority is given
+ to receive but a hook macro is provided anyway...*/
+ LPC17xx_SPI_SSP_ERROR_HOOK(spip);
+ }
+ ssp->ICR = ICR_RT | ICR_ROR;
+ while ((ssp->SR & SR_RNE) != 0) {
+ if (spip->rxptr != NULL) {
+ if ((ssp->CR0 & CR0_DSSMASK) > CR0_DSS8BIT) {
+ uint16_t *p = spip->rxptr;
+ *p++ = ssp->DR;
+ spip->rxptr = p;
+ }
+ else {
+ uint8_t *p = spip->rxptr;
+ *p++ = ssp->DR;
+ spip->rxptr = p;
+ }
+ }
+ else
+ (void)ssp->DR;
+ if (--spip->rxcnt == 0) {
+ chDbgAssert(spip->txcnt == 0,
+ "spi_serve_interrupt(), #1", "counter out of synch");
+ /* Stops the IRQ sources.*/
+ ssp->IMSC = 0;
+ /* Portable SPI ISR code defined in the high level driver, note, it is
+ a macro.*/
+ _spi_isr_code(spip);
+ return;
+ }
+ }
+ ssp_fifo_preload(spip);
+ if (spip->txcnt == 0)
+ ssp->IMSC = IMSC_ROR | IMSC_RT | IMSC_RX;
+}
+
+/*===========================================================================*/
+/* Driver interrupt handlers. */
+/*===========================================================================*/
+
+#if LPC17xx_SPI_USE_SSP0 || defined(__DOXYGEN__)
+/**
+ * @brief SSP0 interrupt handler.
+ *
+ * @isr
+ */
+CH_IRQ_HANDLER(Vector78) {
+
+ CH_IRQ_PROLOGUE();
+
+ spi_serve_interrupt(&SPID1);
+
+ CH_IRQ_EPILOGUE();
+}
+#endif
+
+#if LPC17xx_SPI_USE_SSP1 || defined(__DOXYGEN__)
+/**
+ * @brief SSP1 interrupt handler.
+ *
+ * @isr
+ */
+CH_IRQ_HANDLER(Vector7C) {
+
+ CH_IRQ_PROLOGUE();
+
+ spi_serve_interrupt(&SPID2);
+
+ CH_IRQ_EPILOGUE();
+}
+#endif
+
+/*===========================================================================*/
+/* Driver exported functions. */
+/*===========================================================================*/
+
+/**
+ * @brief Low level SPI driver initialization.
+ *
+ * @notapi
+ */
+void spi_lld_init(void) {
+
+#if LPC17xx_SPI_USE_SSP0
+ spiObjectInit(&SPID1);
+ SPID1.ssp = LPC_SSP0;
+#endif /* LPC17xx_SPI_USE_SSP0 */
+
+#if LPC17xx_SPI_USE_SSP1
+ spiObjectInit(&SPID2);
+ SPID2.ssp = LPC_SSP1;
+#endif /* LPC17xx_SPI_USE_SSP0 */
+}
+
+/**
+ * @brief Configures and activates the SPI peripheral.
+ *
+ * @param[in] spip pointer to the @p SPIDriver object
+ *
+ * @notapi
+ */
+void spi_lld_start(SPIDriver *spip) {
+
+ if (spip->state == SPI_STOP) {
+ /* Clock activation.*/
+#if LPC17xx_SPI_USE_SSP0
+ if (&SPID1 == spip) {
+ LPC_SC->PCONP |= (1UL << 21);
+ LPC_SC->PCLKSEL0 &= (PCLKSEL_MASK << 20);
+ LPC_SC->PCLKSEL0 |= (LPC17xx_SPI_SSP0_PCLKSEL << 20);
+ nvicEnableVector(SSP0_IRQn,
+ CORTEX_PRIORITY_MASK(LPC17xx_SPI_SSP0_IRQ_PRIORITY));
+ }
+#endif
+#if LPC17xx_SPI_USE_SSP1
+ if (&SPID2 == spip) {
+ LPC_SC->PCONP |= (1UL << 10);
+ LPC_SC->PCLKSEL1 &= (PCLKSEL_MASK << 10);
+ LPC_SC->PCLKSEL1 |= (LPC17xx_SPI_SSP0_PCLKSEL << 10);
+ nvicEnableVector(SSP1_IRQn,
+ CORTEX_PRIORITY_MASK(LPC17xx_SPI_SSP1_IRQ_PRIORITY));
+ }
+#endif
+ }
+ /* Configuration.*/
+ spip->ssp->CR1 = 0;
+ spip->ssp->ICR = ICR_RT | ICR_ROR;
+ spip->ssp->CR0 = spip->config->cr0;
+ spip->ssp->CPSR = spip->config->cpsr;
+ spip->ssp->CR1 = CR1_SSE;
+}
+
+/**
+ * @brief Deactivates the SPI peripheral.
+ *
+ * @param[in] spip pointer to the @p SPIDriver object
+ *
+ * @notapi
+ */
+void spi_lld_stop(SPIDriver *spip) {
+
+ if (spip->state != SPI_STOP) {
+ spip->ssp->CR1 = 0;
+ spip->ssp->CR0 = 0;
+ spip->ssp->CPSR = 0;
+#if LPC17xx_SPI_USE_SSP0
+ if (&SPID1 == spip) {
+ LPC_SC->PCONP &= ~(1UL << 21);
+ nvicDisableVector(SSP0_IRQn);
+ }
+#endif
+#if LPC17xx_SPI_USE_SSP1
+ if (&SPID2 == spip) {
+ LPC_SC->PCONP &= ~(1UL << 10);
+ nvicDisableVector(SSP1_IRQn);
+ }
+#endif
+ }
+}
+
+/**
+ * @brief Asserts the slave select signal and prepares for transfers.
+ *
+ * @param[in] spip pointer to the @p SPIDriver object
+ *
+ * @notapi
+ */
+void spi_lld_select(SPIDriver *spip) {
+
+ palClearPad(spip->config->ssport, spip->config->sspad);
+}
+
+/**
+ * @brief Deasserts the slave select signal.
+ * @details The previously selected peripheral is unselected.
+ *
+ * @param[in] spip pointer to the @p SPIDriver object
+ *
+ * @notapi
+ */
+void spi_lld_unselect(SPIDriver *spip) {
+
+ palSetPad(spip->config->ssport, spip->config->sspad);
+}
+
+/**
+ * @brief Ignores data on the SPI bus.
+ * @details This function transmits a series of idle words on the SPI bus and
+ * ignores the received data. This function can be invoked even
+ * when a slave select signal has not been yet asserted.
+ *
+ * @param[in] spip pointer to the @p SPIDriver object
+ * @param[in] n number of words to be ignored
+ *
+ * @notapi
+ */
+void spi_lld_ignore(SPIDriver *spip, size_t n) {
+
+ spip->rxptr = NULL;
+ spip->txptr = NULL;
+ spip->rxcnt = spip->txcnt = n;
+ ssp_fifo_preload(spip);
+ spip->ssp->IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX;
+}
+
+/**
+ * @brief Exchanges data on the SPI bus.
+ * @details This asynchronous function starts a simultaneous transmit/receive
+ * operation.
+ * @post At the end of the operation the configured callback is invoked.
+ * @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.
+ *
+ * @param[in] spip pointer to the @p SPIDriver object
+ * @param[in] n number of words to be exchanged
+ * @param[in] txbuf the pointer to the transmit buffer
+ * @param[out] rxbuf the pointer to the receive buffer
+ *
+ * @notapi
+ */
+void spi_lld_exchange(SPIDriver *spip, size_t n,
+ const void *txbuf, void *rxbuf) {
+
+ spip->rxptr = rxbuf;
+ spip->txptr = txbuf;
+ spip->rxcnt = spip->txcnt = n;
+ ssp_fifo_preload(spip);
+ spip->ssp->IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX;
+}
+
+/**
+ * @brief Sends data over the SPI bus.
+ * @details This asynchronous function starts a transmit operation.
+ * @post At the end of the operation the configured callback is invoked.
+ * @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.
+ *
+ * @param[in] spip pointer to the @p SPIDriver object
+ * @param[in] n number of words to send
+ * @param[in] txbuf the pointer to the transmit buffer
+ *
+ * @notapi
+ */
+void spi_lld_send(SPIDriver *spip, size_t n, const void *txbuf) {
+
+ spip->rxptr = NULL;
+ spip->txptr = txbuf;
+ spip->rxcnt = spip->txcnt = n;
+ ssp_fifo_preload(spip);
+ spip->ssp->IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX;
+}
+
+/**
+ * @brief Receives data from the SPI bus.
+ * @details This asynchronous function starts a receive operation.
+ * @post At the end of the operation the configured callback is invoked.
+ * @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.
+ *
+ * @param[in] spip pointer to the @p SPIDriver object
+ * @param[in] n number of words to receive
+ * @param[out] rxbuf the pointer to the receive buffer
+ *
+ * @notapi
+ */
+void spi_lld_receive(SPIDriver *spip, size_t n, void *rxbuf) {
+
+ spip->rxptr = rxbuf;
+ spip->txptr = NULL;
+ spip->rxcnt = spip->txcnt = n;
+ ssp_fifo_preload(spip);
+ spip->ssp->IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX;
+}
+
+/**
+ * @brief Exchanges one frame using a polled wait.
+ * @details This synchronous function exchanges one frame using a polled
+ * synchronization method. This function is useful when exchanging
+ * small amount of data on high speed channels, usually in this
+ * situation is much more efficient just wait for completion using
+ * polling than suspending the thread waiting for an interrupt.
+ *
+ * @param[in] spip pointer to the @p SPIDriver object
+ * @param[in] frame the data frame to send over the SPI bus
+ * @return The received data frame from the SPI bus.
+ */
+uint16_t spi_lld_polled_exchange(SPIDriver *spip, uint16_t frame) {
+
+ spip->ssp->DR = (uint32_t)frame;
+ while ((spip->ssp->SR & SR_RNE) == 0)
+ ;
+ return (uint16_t)spip->ssp->DR;
+}
+
+#endif /* HAL_USE_SPI */
+
+/** @} */
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