340 lines
10 KiB
C
340 lines
10 KiB
C
/*
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ChibiOS/RT - Copyright (C) 2006-2013 Giovanni Di Sirio
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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/**
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* @file LPC214x/spi_lld.c
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* @brief LPC214x low level SPI driver code.
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*
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* @addtogroup SPI
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* @{
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*/
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#include "ch.h"
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#include "hal.h"
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#if HAL_USE_SPI || defined(__DOXYGEN__)
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/*===========================================================================*/
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/* Driver exported variables. */
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/*===========================================================================*/
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#if LPC214x_SPI_USE_SSP || defined(__DOXYGEN__)
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/** @brief SPI1 driver identifier.*/
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SPIDriver SPID1;
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#endif
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/*===========================================================================*/
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/* Driver local variables and types. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Driver local functions. */
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/*===========================================================================*/
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/**
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* @brief Preloads the transmit FIFO.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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*/
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static void ssp_fifo_preload(SPIDriver *spip) {
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SSP *ssp = spip->ssp;
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uint32_t n = spip->txcnt > LPC214x_SSP_FIFO_DEPTH ?
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LPC214x_SSP_FIFO_DEPTH : spip->txcnt;
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while(((ssp->SSP_SR & SR_TNF) != 0) && (n > 0)) {
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if (spip->txptr != NULL) {
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if ((ssp->SSP_CR0 & CR0_DSSMASK) > CR0_DSS8BIT)
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ssp->SSP_DR = *(uint16_t *)spip->txptr++;
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else
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ssp->SSP_DR = *(uint8_t *)spip->txptr++;
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}
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else
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ssp->SSP_DR = 0xFFFFFFFF;
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n--;
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spip->txcnt--;
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}
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}
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#if defined(__GNUC__)
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__attribute__((noinline))
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#endif
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/**
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* @brief Common IRQ handler.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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*/
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static void serve_interrupt(SPIDriver *spip) {
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SSP *ssp = spip->ssp;
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if ((ssp->SSP_MIS & MIS_ROR) != 0) {
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/* The overflow condition should never happen because priority is given
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to receive but a hook macro is provided anyway...*/
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LPC214x_SPI_SSP_ERROR_HOOK();
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}
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ssp->SSP_ICR = ICR_RT | ICR_ROR;
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while ((ssp->SSP_SR & SR_RNE) != 0) {
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if (spip->rxptr != NULL) {
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if ((ssp->SSP_CR0 & CR0_DSSMASK) > CR0_DSS8BIT)
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*(uint16_t *)spip->rxptr++ = ssp->SSP_DR;
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else
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*(uint8_t *)spip->rxptr++ = ssp->SSP_DR;
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}
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else
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(void)ssp->SSP_DR;
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if (--spip->rxcnt == 0) {
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chDbgAssert(spip->txcnt == 0,
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"spi_serve_interrupt(), #1", "counter out of synch");
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/* Stops the IRQ sources.*/
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ssp->SSP_IMSC = 0;
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/* Portable SPI ISR code defined in the high level driver, note, it is
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a macro.*/
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_spi_isr_code(spip);
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return;
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}
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}
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ssp_fifo_preload(spip);
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if (spip->txcnt == 0)
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ssp->SSP_IMSC = IMSC_ROR | IMSC_RT | IMSC_RX;
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}
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/*===========================================================================*/
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/* Driver interrupt handlers. */
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/*===========================================================================*/
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#if LPC214x_SPI_USE_SSP || defined(__DOXYGEN__)
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/**
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* @brief SPI1 interrupt handler.
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*
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* @isr
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*/
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CH_IRQ_HANDLER(SPI1IrqHandler) {
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CH_IRQ_PROLOGUE();
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serve_interrupt(&SPID1);
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VICVectAddr = 0;
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CH_IRQ_EPILOGUE();
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}
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#endif
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/*===========================================================================*/
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/* Driver exported functions. */
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/*===========================================================================*/
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/**
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* @brief Low level SPI driver initialization.
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*
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* @notapi
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*/
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void spi_lld_init(void) {
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#if LPC214x_SPI_USE_SSP
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spiObjectInit(&SPID1);
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SPID1.ssp = SSPBase;
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SetVICVector(SPI1IrqHandler, LPC214x_SPI_SSP_IRQ_PRIORITY, SOURCE_SPI1);
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#endif
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}
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/**
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* @brief Configures and activates the SPI peripheral.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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*
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* @notapi
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*/
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void spi_lld_start(SPIDriver *spip) {
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if (spip->state == SPI_STOP) {
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/* Clock activation.*/
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#if LPC214x_SPI_USE_SSP
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if (&SPID1 == spip) {
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PCONP = (PCONP & PCALL) | PCSPI1;
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VICIntEnable = INTMASK(SOURCE_SPI1);
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}
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#endif
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}
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/* Configuration.*/
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spip->ssp->SSP_CR1 = 0;
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/* Emptying the receive FIFO, it happens to not be empty while debugging.*/
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while (spip->ssp->SSP_SR & SR_RNE)
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(void) spip->ssp->SSP_DR;
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spip->ssp->SSP_ICR = ICR_RT | ICR_ROR;
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spip->ssp->SSP_CR0 = spip->config->cr0;
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spip->ssp->SSP_CPSR = spip->config->cpsr;
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spip->ssp->SSP_CR1 = CR1_SSE;
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}
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/**
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* @brief Deactivates the SPI peripheral.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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*
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* @notapi
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*/
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void spi_lld_stop(SPIDriver *spip) {
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if (spip->state != SPI_STOP) {
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spip->ssp->SSP_CR1 = 0;
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spip->ssp->SSP_CR0 = 0;
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spip->ssp->SSP_CPSR = 0;
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#if LPC214x_SPI_USE_SSP
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if (&SPID1 == spip) {
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PCONP = (PCONP & PCALL) & ~PCSPI1;
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VICIntEnClear = INTMASK(SOURCE_SPI1);
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}
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#endif
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}
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}
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/**
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* @brief Asserts the slave select signal and prepares for transfers.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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*
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* @notapi
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*/
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void spi_lld_select(SPIDriver *spip) {
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palClearPad(spip->config->ssport, spip->config->sspad);
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}
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/**
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* @brief Deasserts the slave select signal.
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* @details The previously selected peripheral is unselected.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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*
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* @notapi
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*/
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void spi_lld_unselect(SPIDriver *spip) {
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palSetPad(spip->config->ssport, spip->config->sspad);
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}
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/**
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* @brief Ignores data on the SPI bus.
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* @details This function transmits a series of idle words on the SPI bus and
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* ignores the received data. This function can be invoked even
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* when a slave select signal has not been yet asserted.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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* @param[in] n number of words to be ignored
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*
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* @notapi
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*/
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void spi_lld_ignore(SPIDriver *spip, size_t n) {
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spip->rxptr = NULL;
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spip->txptr = NULL;
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spip->rxcnt = spip->txcnt = n;
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ssp_fifo_preload(spip);
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spip->ssp->SSP_IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX;
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}
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/**
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* @brief Exchanges data on the SPI bus.
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* @details This asynchronous function starts a simultaneous transmit/receive
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* operation.
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* @post At the end of the operation the configured callback is invoked.
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* @note The buffers are organized as uint8_t arrays for data sizes below or
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* equal to 8 bits else it is organized as uint16_t arrays.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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* @param[in] n number of words to be exchanged
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* @param[in] txbuf the pointer to the transmit buffer
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* @param[out] rxbuf the pointer to the receive buffer
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*
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* @notapi
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*/
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void spi_lld_exchange(SPIDriver *spip, size_t n,
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const void *txbuf, void *rxbuf) {
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spip->rxptr = rxbuf;
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spip->txptr = txbuf;
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spip->rxcnt = spip->txcnt = n;
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ssp_fifo_preload(spip);
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spip->ssp->SSP_IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX;
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}
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/**
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* @brief Sends data over the SPI bus.
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* @details This asynchronous function starts a transmit operation.
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* @post At the end of the operation the configured callback is invoked.
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* @note The buffers are organized as uint8_t arrays for data sizes below or
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* equal to 8 bits else it is organized as uint16_t arrays.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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* @param[in] n number of words to send
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* @param[in] txbuf the pointer to the transmit buffer
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*
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* @notapi
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*/
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void spi_lld_send(SPIDriver *spip, size_t n, const void *txbuf) {
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spip->rxptr = NULL;
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spip->txptr = txbuf;
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spip->rxcnt = spip->txcnt = n;
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ssp_fifo_preload(spip);
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spip->ssp->SSP_IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX;
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}
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/**
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* @brief Receives data from the SPI bus.
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* @details This asynchronous function starts a receive operation.
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* @post At the end of the operation the configured callback is invoked.
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* @note The buffers are organized as uint8_t arrays for data sizes below or
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* equal to 8 bits else it is organized as uint16_t arrays.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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* @param[in] n number of words to receive
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* @param[out] rxbuf the pointer to the receive buffer
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*
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* @notapi
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*/
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void spi_lld_receive(SPIDriver *spip, size_t n, void *rxbuf) {
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spip->rxptr = rxbuf;
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spip->txptr = NULL;
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spip->rxcnt = spip->txcnt = n;
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ssp_fifo_preload(spip);
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spip->ssp->SSP_IMSC = IMSC_ROR | IMSC_RT | IMSC_TX | IMSC_RX;
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}
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/**
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* @brief Exchanges one frame using a polled wait.
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* @details This synchronous function exchanges one frame using a polled
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* synchronization method. This function is useful when exchanging
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* small amount of data on high speed channels, usually in this
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* situation is much more efficient just wait for completion using
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* polling than suspending the thread waiting for an interrupt.
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*
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* @param[in] spip pointer to the @p SPIDriver object
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* @param[in] frame the data frame to send over the SPI bus
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* @return The received data frame from the SPI bus.
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*/
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uint16_t spi_lld_polled_exchange(SPIDriver *spip, uint16_t frame) {
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spip->ssp->SSP_DR = (uint32_t)frame;
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while ((spip->ssp->SSP_SR & SR_RNE) == 0)
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;
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return (uint16_t)spip->ssp->SSP_DR;
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}
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#endif /* HAL_USE_SPI */
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/** @} */
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