diff options
Diffstat (limited to 'os/hal/platforms/AVR/spi_lld.c')
| -rw-r--r-- | os/hal/platforms/AVR/spi_lld.c | 395 |
1 files changed, 395 insertions, 0 deletions
diff --git a/os/hal/platforms/AVR/spi_lld.c b/os/hal/platforms/AVR/spi_lld.c new file mode 100644 index 000000000..124411a2b --- /dev/null +++ b/os/hal/platforms/AVR/spi_lld.c @@ -0,0 +1,395 @@ +/*
+ ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
+ 2011,2012,2013 Giovanni Di Sirio.
+
+ This file is part of ChibiOS/RT.
+
+ ChibiOS/RT is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ ChibiOS/RT is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/**
+ * @file AVR/spi_lld.c
+ * @brief AVR SPI subsystem low level driver source.
+ *
+ * @addtogroup SPI
+ * @{
+ */
+
+#include "ch.h"
+#include "hal.h"
+
+#if HAL_USE_SPI || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Driver local definitions. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver exported variables. */
+/*===========================================================================*/
+
+/**
+ * @brief SPI1 driver identifier.
+ */
+#if USE_AVR_SPI || defined(__DOXYGEN__)
+SPIDriver SPID;
+#endif
+
+/*===========================================================================*/
+/* Driver local variables and types. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver local functions. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver interrupt handlers. */
+/*===========================================================================*/
+
+#if USE_AVR_SPI || defined(__DOXYGEN__)
+/**
+ * @brief SPI event interrupt handler.
+ *
+ * @notapi
+ */
+CH_IRQ_HANDLER(SPI_STC_vect) {
+ CH_IRQ_PROLOGUE();
+
+ SPIDriver *spip = &SPID;
+
+ /* spi_lld_exchange */
+ if (spip->rxbuf && spip->txbuf) {
+ spip->rxbuf[spip->rxidx++] = SPDR;
+ if (spip->rxidx == spip->rxbytes) {
+ _spi_isr_code(spip);
+ } else {
+ SPDR = spip->txbuf[spip->txidx++];
+ }
+ /* spi_lld_send */
+ } else if (spip->txbuf) {
+ if (spip->txidx < spip->txbytes) {
+ SPDR = spip->txbuf[spip->txidx++];
+ } else {
+ _spi_isr_code(spip);
+ }
+ /* spi_lld_receive */
+ } else if (spip->rxbuf) {
+ spip->rxbuf[spip->rxidx++] = SPDR;
+ if (spip->rxidx < spip->rxbytes) {
+ /* must keep clocking SCK */
+ SPDR = 0;
+ } else {
+ _spi_isr_code(spip);
+ }
+ /* spi_lld_ignore */
+ } else {
+ if (spip->txidx < spip->txbytes) {
+ SPDR = 0;
+ } else {
+ _spi_isr_code(spip);
+ }
+ }
+
+ CH_IRQ_EPILOGUE();
+}
+#endif /* USE_AVR_SPI */
+
+/*===========================================================================*/
+/* Driver exported functions. */
+/*===========================================================================*/
+
+/**
+ * @brief Low level SPI driver initialization.
+ *
+ * @notapi
+ */
+void spi_lld_init(void) {
+
+#if USE_AVR_SPI
+ /* Driver initialization.*/
+ spiObjectInit(&SPID);
+#endif /* USE_AVR_SPI */
+}
+
+/**
+ * @brief Configures and activates the SPI peripheral.
+ *
+ * @param[in] spip pointer to the @p SPIDriver object
+ *
+ * @notapi
+ */
+void spi_lld_start(SPIDriver *spip) {
+
+ uint8_t dummy;
+
+ /* Configures the peripheral.*/
+
+ if (spip->state == SPI_STOP) {
+ /* Enables the peripheral.*/
+#if USE_AVR_SPI
+ if (&SPID == spip) {
+ /* enable SPI clock */
+ PRR0 &= ~(1 << PRSPI);
+
+ /* SPI interrupt enable, SPI enable, Master mode */
+ SPCR |= ((1 << SPE) | (1 << MSTR));
+
+ spip->config->ssport->dir |= (1 << spip->config->sspad);
+
+ /* XXX: For SPI to work as master, MOSI/SCK must be
+ * configured as outputs on your own code!
+ */
+
+ switch (spip->config->bitorder) {
+ case SPI_LSB_FIRST:
+ SPCR |= (1 << DORD);
+ break;
+ case SPI_MSB_FIRST: /* fallthrough */
+ default:
+ SPCR &= ~(1 << DORD);
+ break;
+ }
+
+ SPCR &= ~((1 << CPOL) | (1 << CPHA));
+ switch (spip->config->mode) {
+ case SPI_MODE_1:
+ SPCR |= (1 << CPHA);
+ break;
+ case SPI_MODE_2:
+ SPCR |= (1 << CPOL);
+ break;
+ case SPI_MODE_3:
+ SPCR |= ((1 << CPOL) | (1 << CPHA));
+ break;
+ case SPI_MODE_0: /* fallthrough */
+ default: break;
+ }
+
+ SPCR &= ~((1 << SPR1) | (1 << SPR0));
+ SPSR &= ~(1 << SPI2X);
+ switch (spip->config->clockrate) {
+ case SPI_SCK_FOSC_2:
+ SPSR |= (1 << SPI2X);
+ break;
+ case SPI_SCK_FOSC_8:
+ SPSR |= (1 << SPI2X);
+ SPCR |= (1 << SPR0);
+ break;
+ case SPI_SCK_FOSC_16:
+ SPCR |= (1 << SPR0);
+ break;
+ case SPI_SCK_FOSC_32:
+ SPSR |= (1 << SPI2X);
+ SPCR |= (1 << SPR1);
+ break;
+ case SPI_SCK_FOSC_64:
+ SPCR |= (1 << SPR1);
+ break;
+ case SPI_SCK_FOSC_128:
+ SPCR |= ((1 << SPR1) | (1 << SPR0));
+ break;
+ case SPI_SCK_FOSC_4: /* fallthrough */
+ default: break;
+ }
+
+ /* dummy reads before enabling interrupt */
+ dummy = SPSR;
+ dummy = SPDR;
+ SPCR |= (1 << SPIE);
+ }
+#endif /* USE_AVR_SPI */
+ }
+}
+
+/**
+ * @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_READY) {
+ /* Resets the peripheral.*/
+
+ /* Disables the peripheral.*/
+#if USE_AVR_SPI
+ if (&SPID == spip) {
+ SPCR &= ((1 << SPIE) | (1 << SPE));
+ spip->config->ssport->dir &= ~(1 << spip->config->sspad);
+ }
+#endif /* USE_AVR_SPI */
+ }
+}
+
+/**
+ * @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) {
+
+ spip->config->ssport->out &= ~(1 << 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) {
+
+ spip->config->ssport->out |= (1 << spip->config->sspad);
+
+}
+
+/**
+ * @brief Ignores data on the SPI bus.
+ * @details This asynchronous function starts the transmission of a series of
+ * idle words on the SPI bus and ignores the received data.
+ * @post At the end of the operation the configured callback is invoked.
+ *
+ * @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->rxbuf = spip->txbuf = NULL;
+ spip->txbytes = n;
+ spip->txidx = 0;
+
+ SPDR = 0;
+}
+
+/**
+ * @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->rxbuf = rxbuf;
+ spip->txbuf = txbuf;
+ spip->txbytes = spip->rxbytes = n;
+ spip->txidx = spip->rxidx = 0;
+
+ SPDR = spip->txbuf[spip->txidx++];
+}
+
+/**
+ * @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->rxbuf = NULL;
+ spip->txbuf = txbuf;
+ spip->txbytes = n;
+ spip->txidx = 0;
+
+ SPDR = spip->txbuf[spip->txidx++];
+}
+
+/**
+ * @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->txbuf = NULL;
+ spip->rxbuf = rxbuf;
+ spip->rxbytes = n;
+ spip->rxidx = 0;
+
+ /* Write dummy byte to start communication */
+ SPDR = 0;
+}
+
+/**
+ * @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) {
+
+ uint16_t spdr = 0;
+ uint8_t dummy;
+
+ /* disable interrupt */
+ SPCR &= ~(1 << SPIE);
+
+ SPDR = frame >> 8;
+ while (!(SPSR & (1 << SPIF))) ;
+ spdr = SPDR << 8;
+
+ SPDR = frame & 0xFF;
+ while (!(SPSR & (1 << SPIF))) ;
+ spdr |= SPDR;
+
+ dummy = SPSR;
+ dummy = SPDR;
+ SPCR |= (1 << SPIE);
+
+ return spdr;
+}
+
+#endif /* HAL_USE_SPI */
+
+/** @} */
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