375 lines
11 KiB
C
375 lines
11 KiB
C
/*
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Copyright (C) 2015 Stephen Caudle
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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 NRF51822/spi_lld.c
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* @brief NRF51822 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 "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 NRF5_SPI_USE_SPI0 || 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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#if NRF5_SPI_USE_SPI1 || defined(__DOXYGEN__)
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/** @brief SPI2 driver identifier.*/
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SPIDriver SPID2;
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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 port_fifo_preload(SPIDriver *spip) {
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NRF_SPI_Type *port = spip->port;
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if (spip->txcnt > 0 && spip->txptr != NULL)
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port->TXD = *(uint8_t *)spip->txptr++;
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else
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port->TXD = 0xFF;
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spip->txcnt--;
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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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NRF_SPI_Type *port = spip->port;
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// Clear SPI READY event flag
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port->EVENTS_READY = 0;
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if (spip->rxptr != NULL) {
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*(uint8_t *)spip->rxptr++ = port->RXD;
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}
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else {
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(void)port->RXD;
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if (--spip->rxcnt == 0) {
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osalDbgAssert(spip->txcnt == 0, "counter out of synch");
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/* Stops the IRQ sources.*/
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spip->port->INTENCLR = (SPI_INTENCLR_READY_Clear << SPI_INTENCLR_READY_Pos);
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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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if (spip->txcnt > 0) {
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port_fifo_preload(spip);
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}
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else {
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spip->port->INTENCLR = (SPI_INTENCLR_READY_Clear << SPI_INTENCLR_READY_Pos);
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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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}
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}
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/*===========================================================================*/
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/* Driver interrupt handlers. */
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/*===========================================================================*/
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#if NRF5_SPI_USE_SPI0 || defined(__DOXYGEN__)
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/**
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* @brief SPI0 interrupt handler.
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*
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* @isr
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*/
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CH_IRQ_HANDLER(Vector4C) {
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CH_IRQ_PROLOGUE();
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serve_interrupt(&SPID1);
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CH_IRQ_EPILOGUE();
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}
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#endif
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#if NRF5_SPI_USE_SPI1 || 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(Vector50) {
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CH_IRQ_PROLOGUE();
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serve_interrupt(&SPID2);
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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 NRF5_SPI_USE_SPI0
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spiObjectInit(&SPID1);
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SPID1.port = NRF_SPI0;
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#endif
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#if NRF5_SPI_USE_SPI1
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spiObjectInit(&SPID2);
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SPID2.port = NRF_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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uint32_t config;
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if (spip->state == SPI_STOP) {
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#if NRF5_SPI_USE_SPI0
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if (&SPID1 == spip)
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nvicEnableVector(SPI0_TWI0_IRQn, NRF5_SPI_SPI0_IRQ_PRIORITY);
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#endif
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#if NRF5_SPI_USE_SPI1
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if (&SPID2 == spip)
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nvicEnableVector(SPI1_TWI1_IRQn, NRF5_SPI_SPI1_IRQ_PRIORITY);
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#endif
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}
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config = spip->config->lsbfirst ?
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(SPI_CONFIG_ORDER_LsbFirst << SPI_CONFIG_ORDER_Pos) :
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(SPI_CONFIG_ORDER_MsbFirst << SPI_CONFIG_ORDER_Pos);
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switch (spip->config->mode) {
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case 1:
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config |= (SPI_CONFIG_CPOL_ActiveLow << SPI_CONFIG_CPOL_Pos);
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config |= (SPI_CONFIG_CPHA_Trailing << SPI_CONFIG_CPHA_Pos);
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break;
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case 2:
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config |= (SPI_CONFIG_CPOL_ActiveHigh << SPI_CONFIG_CPOL_Pos);
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config |= (SPI_CONFIG_CPHA_Leading << SPI_CONFIG_CPHA_Pos);
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break;
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case 3:
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config |= (SPI_CONFIG_CPOL_ActiveHigh << SPI_CONFIG_CPOL_Pos);
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config |= (SPI_CONFIG_CPHA_Trailing << SPI_CONFIG_CPHA_Pos);
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break;
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default:
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config |= (SPI_CONFIG_CPOL_ActiveLow << SPI_CONFIG_CPOL_Pos);
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config |= (SPI_CONFIG_CPHA_Leading << SPI_CONFIG_CPHA_Pos);
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break;
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}
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/* Configuration.*/
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spip->port->CONFIG = config;
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spip->port->PSELSCK = spip->config->sckpad;
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spip->port->PSELMOSI = spip->config->mosipad;
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spip->port->PSELMISO = spip->config->misopad;
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spip->port->FREQUENCY = spip->config->freq;
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spip->port->ENABLE = (SPI_ENABLE_ENABLE_Enabled << SPI_ENABLE_ENABLE_Pos);
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/* clear events flag */
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spip->port->EVENTS_READY = 0;
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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->port->ENABLE = (SPI_ENABLE_ENABLE_Disabled << SPI_ENABLE_ENABLE_Pos);
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spip->port->INTENCLR = (SPI_INTENCLR_READY_Clear << SPI_INTENCLR_READY_Pos);
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#if NRF5_SPI_USE_SPI0
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if (&SPID1 == spip)
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nvicDisableVector(SPI0_TWI0_IRQn);
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#endif
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#if NRF5_SPI_USE_SPI1
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if (&SPID2 == spip)
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nvicDisableVector(SPI1_TWI1_IRQn);
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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(IOPORT1, 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(IOPORT1, 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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port_fifo_preload(spip);
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spip->port->INTENSET = (SPI_INTENCLR_READY_Enabled << SPI_INTENCLR_READY_Pos);
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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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port_fifo_preload(spip);
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spip->port->INTENSET = (SPI_INTENCLR_READY_Enabled << SPI_INTENCLR_READY_Pos);
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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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port_fifo_preload(spip);
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spip->port->INTENSET = (SPI_INTENCLR_READY_Enabled << SPI_INTENCLR_READY_Pos);
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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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port_fifo_preload(spip);
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spip->port->INTENSET = (SPI_INTENCLR_READY_Enabled << SPI_INTENCLR_READY_Pos);
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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->port->TXD = (uint8_t)frame;
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while (spip->port->EVENTS_READY == 0)
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;
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spip->port->EVENTS_READY = 0;
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return spip->port->RXD;
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}
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#endif /* HAL_USE_SPI */
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/** @} */
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