spi.h
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/*
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 <http://www.gnu.org/licenses/>.
---
A special exception to the GPL can be applied should you wish to distribute
a combined work that includes ChibiOS/RT, without being obliged to provide
the source code for any proprietary components. See the file exception.txt
for full details of how and when the exception can be applied.
*/
/**
* @file spi.h
* @brief SPI Driver macros and structures.
*
* @addtogroup SPI
* @{
*/
#ifndef _SPI_H_
#define _SPI_H_
#if HAL_USE_SPI || defined(__DOXYGEN__)
/*===========================================================================*/
/* Driver constants. */
/*===========================================================================*/
/*===========================================================================*/
/* Driver pre-compile time settings. */
/*===========================================================================*/
/**
* @name SPI configuration options
* @{
*/
/**
* @brief Enables synchronous APIs.
* @note Disabling this option saves both code and data space.
*/
#if !defined(SPI_USE_WAIT) || defined(__DOXYGEN__)
#define SPI_USE_WAIT TRUE
#endif
/**
* @brief Enables the @p spiAcquireBus() and @p spiReleaseBus() APIs.
* @note Disabling this option saves both code and data space.
*/
#if !defined(SPI_USE_MUTUAL_EXCLUSION) || defined(__DOXYGEN__)
#define SPI_USE_MUTUAL_EXCLUSION TRUE
#endif
/** @} */
/*===========================================================================*/
/* Derived constants and error checks. */
/*===========================================================================*/
#if SPI_USE_MUTUAL_EXCLUSION && !CH_USE_MUTEXES && !CH_USE_SEMAPHORES
#error "SPI_USE_MUTUAL_EXCLUSION requires CH_USE_MUTEXES and/or CH_USE_SEMAPHORES"
#endif
/*===========================================================================*/
/* Driver data structures and types. */
/*===========================================================================*/
/**
* @brief Driver state machine possible states.
*/
typedef enum {
SPI_UNINIT = 0, /**< Not initialized. */
SPI_STOP = 1, /**< Stopped. */
SPI_READY = 2, /**< Ready. */
SPI_ACTIVE = 3, /**< Exchanging data. */
SPI_COMPLETE = 4 /**< Asynchronous operation complete. */
} spistate_t;
#include "spi_lld.h"
/*===========================================================================*/
/* Driver macros. */
/*===========================================================================*/
/**
* @name Macro Functions
* @{
*/
/**
* @brief Asserts the slave select signal and prepares for transfers.
*
* @param[in] spip pointer to the @p SPIDriver object
*
* @iclass
*/
#define spiSelectI(spip) { \
spi_lld_select(spip); \
}
/**
* @brief Deasserts the slave select signal.
* @details The previously selected peripheral is unselected.
*
* @param[in] spip pointer to the @p SPIDriver object
*
* @iclass
*/
#define spiUnselectI(spip) { \
spi_lld_unselect(spip); \
}
/**
* @brief Ignores data on the SPI bus.
* @details This asynchronous function starts the transmission of a series of
* idle words on the SPI bus and ignores the received data.
* @pre A slave must have been selected using @p spiSelect() or
* @p spiSelectI().
* @post At the end of the operation the configured callback is invoked.
*
* @param[in] spip pointer to the @p SPIDriver object
* @param[in] n number of words to be ignored
*
* @iclass
*/
#define spiStartIgnoreI(spip, n) { \
(spip)->state = SPI_ACTIVE; \
spi_lld_ignore(spip, n); \
}
/**
* @brief Exchanges data on the SPI bus.
* @details This asynchronous function starts a simultaneous transmit/receive
* operation.
* @pre A slave must have been selected using @p spiSelect() or
* @p spiSelectI().
* @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
*
* @iclass
*/
#define spiStartExchangeI(spip, n, txbuf, rxbuf) { \
(spip)->state = SPI_ACTIVE; \
spi_lld_exchange(spip, n, txbuf, rxbuf); \
}
/**
* @brief Sends data over the SPI bus.
* @details This asynchronous function starts a transmit operation.
* @pre A slave must have been selected using @p spiSelect() or
* @p spiSelectI().
* @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
*
* @iclass
*/
#define spiStartSendI(spip, n, txbuf) { \
(spip)->state = SPI_ACTIVE; \
spi_lld_send(spip, n, txbuf); \
}
/**
* @brief Receives data from the SPI bus.
* @details This asynchronous function starts a receive operation.
* @pre A slave must have been selected using @p spiSelect() or
* @p spiSelectI().
* @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
*
* @iclass
*/
#define spiStartReceiveI(spip, n, rxbuf) { \
(spip)->state = SPI_ACTIVE; \
spi_lld_receive(spip, n, rxbuf); \
}
/**
* @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.
* @note This API is implemented as a macro in order to minimize latency.
*
* @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.
*/
#define spiPolledExchange(spip, frame) spi_lld_polled_exchange(spip, frame)
/** @} */
/**
* @name Low Level driver helper macros
* @{
*/
#if SPI_USE_WAIT || defined(__DOXYGEN__)
/**
* @brief Waits for operation completion.
* @details This function waits for the driver to complete the current
* operation.
* @pre An operation must be running while the function is invoked.
* @note No more than one thread can wait on a SPI driver using
* this function.
*
* @param[in] spip pointer to the @p SPIDriver object
*
* @notapi
*/
#define _spi_wait_s(spip) { \
chDbgAssert((spip)->thread == NULL, \
"_spi_wait(), #1", "already waiting"); \
(spip)->thread = chThdSelf(); \
chSchGoSleepS(THD_STATE_SUSPENDED); \
}
/**
* @brief Wakes up the waiting thread.
*
* @param[in] spip pointer to the @p SPIDriver object
*
* @notapi
*/
#define _spi_wakeup_isr(spip) { \
if ((spip)->thread != NULL) { \
Thread *tp = (spip)->thread; \
(spip)->thread = NULL; \
chSysLockFromIsr(); \
chSchReadyI(tp); \
chSysUnlockFromIsr(); \
} \
}
#else /* !SPI_USE_WAIT */
#define _spi_wait_s(spip)
#define _spi_wakeup_isr(spip)
#endif /* !SPI_USE_WAIT */
/**
* @brief Common ISR code.
* @details This code handles the portable part of the ISR code:
* - Callback invocation.
* - Waiting thread wakeup, if any.
* - Driver state transitions.
* .
* @note This macro is meant to be used in the low level drivers
* implementation only.
*
* @param[in] spip pointer to the @p SPIDriver object
*
* @notapi
*/
#define _spi_isr_code(spip) { \
if ((spip)->config->end_cb) { \
(spip)->state = SPI_COMPLETE; \
(spip)->config->end_cb(spip); \
if ((spip)->state == SPI_COMPLETE) \
(spip)->state = SPI_READY; \
} \
else \
(spip)->state = SPI_READY; \
_spi_wakeup_isr(spip); \
}
/** @} */
/*===========================================================================*/
/* External declarations. */
/*===========================================================================*/
#ifdef __cplusplus
extern "C" {
#endif
void spiInit(void);
void spiObjectInit(SPIDriver *spip);
void spiStart(SPIDriver *spip, const SPIConfig *config);
void spiStop(SPIDriver *spip);
void spiSelect(SPIDriver *spip);
void spiUnselect(SPIDriver *spip);
void spiStartIgnore(SPIDriver *spip, size_t n);
void spiStartExchange(SPIDriver *spip, size_t n,
const void *txbuf, void *rxbuf);
void spiStartSend(SPIDriver *spip, size_t n, const void *txbuf);
void spiStartReceive(SPIDriver *spip, size_t n, void *rxbuf);
#if SPI_USE_WAIT
void spiIgnore(SPIDriver *spip, size_t n);
void spiExchange(SPIDriver *spip, size_t n, const void *txbuf, void *rxbuf);
void spiSend(SPIDriver *spip, size_t n, const void *txbuf);
void spiReceive(SPIDriver *spip, size_t n, void *rxbuf);
#endif /* SPI_USE_WAIT */
#if SPI_USE_MUTUAL_EXCLUSION
void spiAcquireBus(SPIDriver *spip);
void spiReleaseBus(SPIDriver *spip);
#endif /* SPI_USE_MUTUAL_EXCLUSION */
#ifdef __cplusplus
}
#endif
#endif /* HAL_USE_SPI */
#endif /* _SPI_H_ */
/** @} */