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tinySA/os/hal/platforms/LPC13xx/spi_lld.c

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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 LPC13xx/spi_lld.c
* @brief LPC13xx low level SPI driver code.
*
* @addtogroup SPI
* @{
*/
#include "ch.h"
#include "hal.h"
#if HAL_USE_SPI || defined(__DOXYGEN__)
/*===========================================================================*/
/* Driver exported variables. */
/*===========================================================================*/
#if LPC13xx_SPI_USE_SSP0 || 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) {
LPC_SSP_TypeDef *ssp = spip->spd_ssp;
uint32_t n = spip->spd_txcnt > LPC13xx_SSP_FIFO_DEPTH ?
LPC13xx_SSP_FIFO_DEPTH : spip->spd_txcnt;
while(((ssp->SR & SR_TNF) != 0) && (n > 0)) {
if (spip->spd_txptr != NULL) {
if ((ssp->CR0 & CR0_DSSMASK) > CR0_DSS8BIT) {
const uint16_t *p = spip->spd_txptr;
ssp->DR = *p++;
spip->spd_txptr = p;
}
else {
const uint8_t *p = spip->spd_txptr;
ssp->DR = *p++;
spip->spd_txptr = p;
}
}
else
ssp->DR = 0xFFFFFFFF;
n--;
spip->spd_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->spd_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...*/
LPC13xx_SPI_SSP_ERROR_HOOK(spip);
}
ssp->ICR = ICR_RT | ICR_ROR;
while ((ssp->SR & SR_RNE) != 0) {
if (spip->spd_rxptr != NULL) {
if ((ssp->CR0 & CR0_DSSMASK) > CR0_DSS8BIT) {
uint16_t *p = spip->spd_rxptr;
*p++ = ssp->DR;
spip->spd_rxptr = p;
}
else {
uint8_t *p = spip->spd_rxptr;
*p++ = ssp->DR;
spip->spd_rxptr = p;
}
}
else
(void)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->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->IMSC = IMSC_ROR | IMSC_RT | IMSC_RX;
}
/*===========================================================================*/
/* Driver interrupt handlers. */
/*===========================================================================*/
#if LPC13xx_SPI_USE_SSP0 || defined(__DOXYGEN__)
/**
* @brief SSP0 interrupt handler.
*
* @isr
*/
CH_IRQ_HANDLER(VectorF4) {
CH_IRQ_PROLOGUE();
spi_serve_interrupt(&SPID1);
CH_IRQ_EPILOGUE();
}
#endif
/*===========================================================================*/
/* Driver exported functions. */
/*===========================================================================*/
/**
* @brief Low level SPI driver initialization.
*
* @notapi
*/
void spi_lld_init(void) {
#if LPC13xx_SPI_USE_SSP0
spiObjectInit(&SPID1);
SPID1.spd_ssp = LPC_SSP;
LPC_IOCON->SCKLOC = LPC13xx_SPI_SCK0_SELECTOR;
#if LPC13xx_SPI_SCK0_SELECTOR == SCK0_IS_PIO0_10
LPC_IOCON->JTAG_TCK_PIO0_10 = 0xC2; /* SCK0 without resistors. */
#elif LPC13xx_SPI_SCK0_SELECTOR == SCK0_IS_PIO2_11
LPC_IOCON->PIO2_11 = 0xC1; /* SCK0 without resistors. */
#else /* LPC13xx_SPI_SCK0_SELECTOR == SCK0_IS_PIO0_6 */
LPC_IOCON->PIO0_6 = 0xC2; /* SCK0 without resistors. */
#endif
LPC_IOCON->PIO0_8 = 0xC1; /* MISO0 without resistors. */
LPC_IOCON->PIO0_9 = 0xC1; /* MOSI0 without resistors. */
#endif /* LPC13xx_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->spd_state == SPI_STOP) {
/* Clock activation.*/
#if LPC13xx_SPI_USE_SSP0
if (&SPID1 == spip) {
LPC_SYSCON->SSPCLKDIV = LPC13xx_SPI_SSP0CLKDIV;
LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 11);
LPC_SYSCON->PRESETCTRL |= 1;
NVICEnableVector(SSP_IRQn,
CORTEX_PRIORITY_MASK(LPC13xx_SPI_SSP0_IRQ_PRIORITY));
}
#endif
}
/* Configuration.*/
spip->spd_ssp->CR1 = 0;
spip->spd_ssp->ICR = ICR_RT | ICR_ROR;
spip->spd_ssp->CR0 = spip->spd_config->spc_cr0;
spip->spd_ssp->CPSR = spip->spd_config->spc_cpsr;
spip->spd_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->CR1 = 0;
spip->spd_ssp->CR0 = 0;
spip->spd_ssp->CPSR = 0;
#if LPC13xx_SPI_USE_SSP0
if (&SPID1 == spip) {
LPC_SYSCON->PRESETCTRL &= ~1;
LPC_SYSCON->SYSAHBCLKCTRL &= ~(1 << 11);
LPC_SYSCON->SSPCLKDIV = 0;
NVICDisableVector(SSP_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->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->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->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->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->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->DR = (uint32_t)frame;
while ((spip->spd_ssp->SR & SR_RNE) == 0)
;
return (uint16_t)spip->spd_ssp->DR;
}
#endif /* HAL_USE_SPI */
/** @} */
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