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/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010 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 LPC214x/spi_lld.c
* @brief LPC214x low level SPI driver code.
*
* @addtogroup SPI
* @{
*/
#include "ch.h"
#include "hal.h"
#if HAL_USE_SPI || defined(__DOXYGEN__)
/*===========================================================================*/
/* Driver exported variables. */
/*===========================================================================*/
#if LPC214x_SPI_USE_SSP || defined(__DOXYGEN__)
/** @brief SPI1 driver identifier.*/
SPIDriver SPID1;
#endif
/*===========================================================================*/
/* Driver local variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver local functions. */
/*===========================================================================*/
/**
* @brief Preloads the transmit FIFO.
*
* @param[in] spip pointer to the @p SPIDriver object
*/
static void ssp_fifo_preload(SPIDriver *spip) {
SSP *ssp = spip->spd_ssp;
uint32_t n = spip->spd_txcnt > LPC214x_SSP_FIFO_DEPTH ?
LPC214x_SSP_FIFO_DEPTH : spip->spd_txcnt;
while(((ssp->SSP_SR & SR_TNF) != 0) && (n > 0)) {
if (spip->spd_txptr != NULL) {
if ((ssp->SSP_CR0 & CR0_DSSMASK) > CR0_DSS8BIT)
ssp->SSP_DR = *(uint16_t *)spip->spd_txptr++;
else
ssp->SSP_DR = *(uint8_t *)spip->spd_txptr++;
}
else
ssp->SSP_DR = 0xFFFFFFFF;
n--;
spip->spd_txcnt--;
}
}
#if defined(__GNUC__)
__attribute__((noinline))
#endif
/**
* @brief Common IRQ handler.
*
* @param[in] spip pointer to the @p SPIDriver object
*/
static void serve_interrupt(SPIDriver *spip) {
SSP *ssp = spip->spd_ssp;
if ((ssp->SSP_MIS & MIS_ROR) != 0) {
/* The overflow condition should never happen because priority is given
to receive but a hook macro is provided anyway...*/
LPC214x_SPI_SSP_ERROR_HOOK();
}
ssp->SSP_ICR = ICR_RT | ICR_ROR;
while ((ssp->SSP_SR & SR_RNE) != 0) {
if (spip->spd_rxptr != NULL) {
if ((ssp->SSP_CR0 & CR0_DSSMASK) > CR0_DSS8BIT)
*(uint16_t *)spip->spd_rxptr++ = ssp->SSP_DR;
else
*(uint8_t *)spip->spd_rxptr++ = ssp->SSP_DR;
}
else
(void)ssp->SSP_DR;
if (--spip->spd_rxcnt == 0) {
chDbgAssert(spip->spd_txcnt == 0,
"spi_serve_interrupt(), #1", "counter out of synch");
/* Stops the IRQ sources.*/
ssp->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->spd_txcnt == 0)
ssp->SSP_IMSC = IMSC_ROR | IMSC_RT | IMSC_RX;
}
/*===========================================================================*/
/* Driver interrupt handlers. */
/*===========================================================================*/
#if LPC214x_SPI_USE_SSP || defined(__DOXYGEN__)
/**
* @brief SPI1 interrupt handler.
*
* @isr
*/
CH_IRQ_HANDLER(SPI1IrqHandler) {
CH_IRQ_PROLOGUE();
serve_interrupt(&SPID1);
VICVectAddr = 0;
CH_IRQ_EPILOGUE();
}
#endif
/*===========================================================================*/
/* Driver exported functions. */
/*===========================================================================*/
/**
* @brief Low level SPI driver initialization.
*
* @notapi
*/
void spi_lld_init(void) {
#if LPC214x_SPI_USE_SSP
spiObjectInit(&SPID1);
SPID1.spd_ssp = SSPBase;
SetVICVector(SPI1IrqHandler, LPC214x_SPI_SSP_IRQ_PRIORITY, SOURCE_SPI1);
#endif
}
/**
* @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->spd_state == SPI_STOP) {
/* Clock activation.*/
#if LPC214x_SPI_USE_SSP
if (&SPID1 == spip) {
PCONP = (PCONP & PCALL) | PCSPI1;
VICIntEnable = INTMASK(SOURCE_SPI1);
}
#endif
}
/* Configuration.*/
spip->spd_ssp->SSP_CR1 = 0;
/* Emptying the receive FIFO, it happens to not be empty while debugging.*/
while (spip->spd_ssp->SSP_SR & SR_RNE)
(void) spip->spd_ssp->SSP_DR;
spip->spd_ssp->SSP_ICR = ICR_RT | ICR_ROR;
spip->spd_ssp->SSP_CR0 = spip->spd_config->spc_cr0;
spip->spd_ssp->SSP_CPSR = spip->spd_config->spc_cpsr;
spip->spd_ssp->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->spd_state != SPI_STOP) {
spip->spd_ssp->SSP_CR1 = 0;
spip->spd_ssp->SSP_CR0 = 0;
spip->spd_ssp->SSP_CPSR = 0;
#if LPC214x_SPI_USE_SSP
if (&SPID1 == spip) {
PCONP = (PCONP & PCALL) & ~PCSPI1;
VICIntEnClear = INTMASK(SOURCE_SPI1);
}
#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->spd_config->spc_ssport, spip->spd_config->spc_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->spd_config->spc_ssport, spip->spd_config->spc_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->spd_rxptr = NULL;
spip->spd_txptr = NULL;
spip->spd_rxcnt = spip->spd_txcnt = n;
ssp_fifo_preload(spip);
spip->spd_ssp->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->spd_rxptr = rxbuf;
spip->spd_txptr = txbuf;
spip->spd_rxcnt = spip->spd_txcnt = n;
ssp_fifo_preload(spip);
spip->spd_ssp->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->spd_rxptr = NULL;
spip->spd_txptr = txbuf;
spip->spd_rxcnt = spip->spd_txcnt = n;
ssp_fifo_preload(spip);
spip->spd_ssp->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->spd_rxptr = rxbuf;
spip->spd_txptr = NULL;
spip->spd_rxcnt = spip->spd_txcnt = n;
ssp_fifo_preload(spip);
spip->spd_ssp->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->spd_ssp->SSP_DR = (uint32_t)frame;
while ((spip->spd_ssp->SSP_SR & SR_RNE) == 0)
;
return (uint16_t)spip->spd_ssp->SSP_DR;
}
#endif /* HAL_USE_SPI */
/** @} */
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