/* ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010, 2011,2012 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 . */ /** * @file STM8S/spi_lld.c * @brief STM8S low level SPI driver code. * * @addtogroup SPI * @{ */ #include "ch.h" #include "hal.h" #if HAL_USE_SPI || defined(__DOXYGEN__) /*===========================================================================*/ /* Driver exported variables. */ /*===========================================================================*/ #if STM8S_SPI_USE_SPI || defined(__DOXYGEN__) /** @brief SPI1 driver identifier.*/ SPIDriver SPID1; #endif /*===========================================================================*/ /* Driver local variables. */ /*===========================================================================*/ /*===========================================================================*/ /* Driver local functions. */ /*===========================================================================*/ /*===========================================================================*/ /* Driver interrupt handlers. */ /*===========================================================================*/ #if STM8S_SPI_USE_SPI || defined(__DOXYGEN__) /** * @brief IRQ 10 service routine. * * @isr */ CH_IRQ_HANDLER(10) { CH_IRQ_PROLOGUE(); if ((SPI->SR & SPI_SR_OVR) != 0) { /* The overflow condition should never happen because priority is given to receive but a hook macro is provided anyway...*/ STM8S_SPI_ERROR_HOOK(&SPID1); } /* Handling the DR register like it is a FIFO with depth>1 in order to handle the case where a frame arrives immediately after reading the DR register.*/ while ((SPI->SR & SPI_SR_RXNE) != 0) { if (SPID1.rxptr != NULL) *SPID1.rxptr++ = SPI->DR; else (void)SPI->DR; if (--SPID1.rxcnt == 0) { chDbgAssert(SPID1.txcnt == 0, "IRQ10, #1", "counter out of synch"); /* Stops all the IRQ sources.*/ SPI->ICR = 0; /* Portable SPI ISR code defined in the high level driver, note, it is a macro.*/ _spi_isr_code(&SPID1); /* Goto because it is mandatory to go through the epilogue, cannot just return.*/ goto exit_isr; } } /* Loading the DR register.*/ if ((SPI->SR & SPI_SR_TXE) != 0) { if (SPID1.txptr != NULL) SPI->DR = *SPID1.txptr++; else SPI->DR = 0xFF; } exit_isr: CH_IRQ_EPILOGUE(); } #endif /*===========================================================================*/ /* Driver exported functions. */ /*===========================================================================*/ /** * @brief Low level SPI driver initialization. * * @notapi */ void spi_lld_init(void) { #if STM8S_SPI_USE_SPI spiObjectInit(&SPID1); #endif /* STM8S_SPI_USE_SPI */ } /** * @brief Configures and activates the SPI peripheral. * * @param[in] spip pointer to the @p SPIDriver object * * @notapi */ void spi_lld_start(SPIDriver *spip) { /* Clock activation.*/ CLK->PCKENR1 |= CLK_PCKENR1_SPI; /* PCKEN11, clock source. */ /* Configuration.*/ SPI->CR1 = 0; SPI->CR1 = spip->config->cr1 | SPI_CR1_MSTR; SPI->CR2 = SPI_CR2_SSI | SPI_CR2_SSM; SPI->CR1 |= SPI_CR1_SPE; } /** * @brief Deactivates the SPI peripheral. * * @param[in] spip pointer to the @p SPIDriver object * * @notapi */ void spi_lld_stop(SPIDriver *spip) { (void)spip; /* Reset state.*/ SPI->CR1 = 0; SPI->CR2 = 0; SPI->ICR = 0; /* Clock de-activation.*/ CLK->PCKENR1 &= (uint8_t)~CLK_PCKENR1_SPI; /* PCKEN11, clock source. */ } /** * @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; SPI->ICR = SPI_ICR_TXEI | SPI_ICR_RXEI | SPI_ICR_ERRIE; } /** * @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; SPI->ICR = SPI_ICR_TXEI | SPI_ICR_RXEI | SPI_ICR_ERRIE; } /** * @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; SPI->ICR = SPI_ICR_TXEI | SPI_ICR_RXEI | SPI_ICR_ERRIE; } /** * @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; SPI->ICR = SPI_ICR_TXEI | SPI_ICR_RXEI | SPI_ICR_ERRIE; } /** * @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. */ uint8_t spi_lld_polled_exchange(SPIDriver *spip, uint8_t frame) { (void)spip; SPI->DR = (uint32_t)frame; while ((SPI->SR & SPI_SR_RXNE) == 0) ; return (uint16_t)SPI->DR; } #endif /* HAL_USE_SPI */ /** @} */