diff --git a/drivers/SPI.h b/drivers/SPI.h index 7c8e7d6103..363bbb9142 100644 --- a/drivers/SPI.h +++ b/drivers/SPI.h @@ -36,39 +36,44 @@ namespace mbed { /** \addtogroup drivers */ -/** A SPI Master, used for communicating with SPI slave devices +/** A SPI Master, used for communicating with SPI slave devices. * - * The default format is set to 8-bits, mode 0, and a clock frequency of 1MHz + * The default format is set to 8-bits, mode 0, and a clock frequency of 1MHz. * * Most SPI devices will also require Chip Select and Reset signals. These - * can be controlled using DigitalOut pins + * can be controlled using DigitalOut pins. * * @note Synchronization level: Thread safe * - * Example: + * Example of how to send a byte to a SPI slave and record the response: * @code - * // Send a byte to a SPI slave, and record the response - * * #include "mbed.h" * - * // hardware ssel (where applicable) - * //SPI device(p5, p6, p7, p8); // mosi, miso, sclk, ssel + * SPI device(SPI_MOSI, SPI_MISO, SPI_SCLK) * - * // software ssel - * SPI device(p5, p6, p7); // mosi, miso, sclk - * DigitalOut cs(p8); // ssel + * DigitalOut chip_select(SPI_CS); * * int main() { - * // hardware ssel (where applicable) - * //int response = device.write(0xFF); - * * device.lock(); - * // software ssel - * cs = 0; - * int response = device.write(0xFF); - * cs = 1; - * device.unlock(); + * chip_select = 0; * + * int response = device.write(0xFF); + * + * chip_select = 1; + * device.unlock(); + * } + * @endcode + * + * Example using hardware Chip Select line: + * @code + * #include "mbed.h" + * + * SPI device(SPI_MOSI, SPI_MISO, SPI_SCLK, SPI_CS) + * + * int main() { + * device.lock(); + * int response = device.write(0xFF); + * device.unlock(); * } * @endcode * @ingroup drivers @@ -77,22 +82,22 @@ class SPI : private NonCopyable { public: - /** Create a SPI master connected to the specified pins + /** Create a SPI master connected to the specified pins. * - * mosi or miso can be specified as NC if not used + * @note You can specify mosi or miso as NC if not used. * - * @param mosi SPI Master Out, Slave In pin - * @param miso SPI Master In, Slave Out pin - * @param sclk SPI Clock pin - * @param ssel SPI chip select pin + * @param mosi SPI Master Out, Slave In pin. + * @param miso SPI Master In, Slave Out pin. + * @param sclk SPI Clock pin. + * @param ssel SPI Chip Select pin. */ SPI(PinName mosi, PinName miso, PinName sclk, PinName ssel = NC); virtual ~SPI(); - /** Configure the data transmission format + /** Configure the data transmission format. * - * @param bits Number of bits per SPI frame (4 - 16) - * @param mode Clock polarity and phase mode (0 - 3) + * @param bits Number of bits per SPI frame (4 - 16). + * @param mode Clock polarity and phase mode (0 - 3). * * @code * mode | POL PHA @@ -105,51 +110,50 @@ public: */ void format(int bits, int mode = 0); - /** Set the spi bus clock frequency + /** Set the SPI bus clock frequency. * - * @param hz SCLK frequency in hz (default = 1MHz) + * @param hz Clock frequency in Hz (default = 1MHz). */ void frequency(int hz = 1000000); - /** Write to the SPI Slave and return the response + /** Write to the SPI Slave and return the response. * - * @param value Data to be sent to the SPI slave + * @param value Data to be sent to the SPI slave. * - * @returns - * Response from the SPI slave + * @return Response from the SPI slave. */ virtual int write(int value); - /** Write to the SPI Slave and obtain the response + /** Write to the SPI Slave and obtain the response. * * The total number of bytes sent and received will be the maximum of * tx_length and rx_length. The bytes written will be padded with the * value 0xff. * - * @param tx_buffer Pointer to the byte-array of data to write to the device - * @param tx_length Number of bytes to write, may be zero - * @param rx_buffer Pointer to the byte-array of data to read from the device - * @param rx_length Number of bytes to read, may be zero - * @returns + * @param tx_buffer Pointer to the byte-array of data to write to the device. + * @param tx_length Number of bytes to write, may be zero. + * @param rx_buffer Pointer to the byte-array of data to read from the device. + * @param rx_length Number of bytes to read, may be zero. + * @return * The number of bytes written and read from the device. This is * maximum of tx_length and rx_length. */ virtual int write(const char *tx_buffer, int tx_length, char *rx_buffer, int rx_length); - /** Acquire exclusive access to this SPI bus + /** Acquire exclusive access to this SPI bus. */ virtual void lock(void); - /** Release exclusive access to this SPI bus + /** Release exclusive access to this SPI bus. */ virtual void unlock(void); - /** Set default write data + /** Set default write data. * SPI requires the master to send some data during a read operation. * Different devices may require different default byte values. * For example: A SD Card requires default bytes to be 0xFF. * - * @param data Default character to be transmitted while read operation + * @param data Default character to be transmitted during a read operation. */ void set_default_write_value(char data); @@ -157,17 +161,20 @@ public: /** Start non-blocking SPI transfer using 8bit buffers. * - * This function locks the deep sleep until any event has occurred + * This function locks the deep sleep until any event has occurred. * * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed, - * the default SPI value is sent - * @param tx_length The length of TX buffer in bytes + * the default SPI value is sent. + * @param tx_length The length of TX buffer in bytes. * @param rx_buffer The RX buffer which is used for received data. If NULL is passed, - * received data are ignored - * @param rx_length The length of RX buffer in bytes - * @param callback The event callback function - * @param event The logical OR of events to modify. Look at spi hal header file for SPI events. - * @return Zero if the transfer has started, or -1 if SPI peripheral is busy + * received data are ignored. + * @param rx_length The length of RX buffer in bytes. + * @param callback The event callback function. + * @param event The event mask of events to modify. @see spi_api.h for SPI events. + * + * @return Operation result. + * @retval 0 If the transfer has started. + * @retval -1 If SPI peripheral is busy. */ template int transfer(const Type *tx_buffer, int tx_length, Type *rx_buffer, int rx_length, const event_callback_t &callback, int event = SPI_EVENT_COMPLETE) @@ -179,75 +186,85 @@ public: return 0; } - /** Abort the on-going SPI transfer, and continue with transfer's in the queue if any. + /** Abort the on-going SPI transfer, and continue with transfers in the queue, if any. */ void abort_transfer(); - /** Clear the transaction buffer + /** Clear the queue of transfers. */ void clear_transfer_buffer(); - /** Clear the transaction buffer and abort on-going transfer. + /** Clear the queue of transfers and abort the on-going transfer. */ void abort_all_transfers(); - /** Configure DMA usage suggestion for non-blocking transfers + /** Configure DMA usage suggestion for non-blocking transfers. * - * @param usage The usage DMA hint for peripheral - * @return Zero if the usage was set, -1 if a transaction is on-going - */ + * @param usage The usage DMA hint for peripheral. + * + * @return Result of the operation. + * @retval 0 The usage was set. + * @retval -1 Usage cannot be set as there is an ongoing transaction. + */ int set_dma_usage(DMAUsage usage); protected: - /** SPI IRQ handler - * - */ + /** SPI interrupt handler. + */ void irq_handler_asynch(void); - /** Common transfer method + /** Start the transfer or put it on the queue. * * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed, * the default SPI value is sent - * @param tx_length The length of TX buffer in bytes + * @param tx_length The length of TX buffer in bytes. * @param rx_buffer The RX buffer which is used for received data. If NULL is passed, - * received data are ignored - * @param rx_length The length of RX buffer in bytes - * @param bit_width The buffers element width - * @param callback The event callback function - * @param event The logical OR of events to modify - * @return Zero if the transfer has started or was added to the queue, or -1 if SPI peripheral is busy/buffer is full - */ + * received data are ignored. + * @param rx_length The length of RX buffer in bytes. + * @param bit_width The buffers element width in bits. + * @param callback The event callback function. + * @param event The event mask of events to modify. + * + * @return Operation success. + * @retval 0 A transfer was started or added to the queue. + * @retval -1 Transfer can't be added because queue is full. + */ int transfer(const void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t &callback, int event); - /** + /** Put a transfer on the transfer queue. * * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed, - * the default SPI value is sent - * @param tx_length The length of TX buffer in bytes + * the default SPI value is sent. + * @param tx_length The length of TX buffer in bytes. * @param rx_buffer The RX buffer which is used for received data. If NULL is passed, - * received data are ignored - * @param rx_length The length of RX buffer in bytes - * @param bit_width The buffers element width - * @param callback The event callback function - * @param event The logical OR of events to modify - * @return Zero if a transfer was added to the queue, or -1 if the queue is full - */ + * received data are ignored. + * @param rx_length The length of RX buffer in bytes. + * @param bit_width The buffers element width in bits. + * @param callback The event callback function. + * @param event The event mask of events to modify. + * + * @return Operation success. + * @retval 0 A transfer was added to the queue. + * @retval -1 Transfer can't be added because queue is full. + */ int queue_transfer(const void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t &callback, int event); - /** Configures a callback, spi peripheral and initiate a new transfer + /** Configure a callback, SPI peripheral, and initiate a new transfer. * * @param tx_buffer The TX buffer with data to be transfered. If NULL is passed, - * the default SPI value is sent - * @param tx_length The length of TX buffer in bytes + * the default SPI value is sent. + * @param tx_length The length of TX buffer in bytes. * @param rx_buffer The RX buffer which is used for received data. If NULL is passed, - * received data are ignored - * @param rx_length The length of RX buffer in bytes - * @param bit_width The buffers element width - * @param callback The event callback function - * @param event The logical OR of events to modify - */ + * received data are ignored. + * @param rx_length The length of RX buffer in bytes. + * @param bit_width The buffers element width. + * @param callback The event callback function. + * @param event The event mask of events to modify. + */ void start_transfer(const void *tx_buffer, int tx_length, void *rx_buffer, int rx_length, unsigned char bit_width, const event_callback_t &callback, int event); +#if !defined(DOXYGEN_ONLY) + private: /** Lock deep sleep only if it is not yet locked */ void lock_deep_sleep(); @@ -258,44 +275,63 @@ private: #if TRANSACTION_QUEUE_SIZE_SPI - /** Start a new transaction + /** Start a new transaction. * - * @param data Transaction data - */ + * @param data Transaction data. + */ void start_transaction(transaction_t *data); - /** Dequeue a transaction - * - */ + /** Dequeue a transaction and start the transfer if there was one pending. + */ void dequeue_transaction(); + + /* Queue of pending transfers */ static CircularBuffer, TRANSACTION_QUEUE_SIZE_SPI> _transaction_buffer; #endif -#endif +#endif //!defined(DOXYGEN_ONLY) + +#endif //DEVICE_SPI_ASYNCH + +#if !defined(DOXYGEN_ONLY) protected: + /* Internal SPI object identifying the resources */ spi_t _spi; #if DEVICE_SPI_ASYNCH + /* Interrupt */ CThunk _irq; + /* Interrupt handler callback */ event_callback_t _callback; + /* Current preferred DMA mode @see dma_api.h */ DMAUsage _usage; + /* Current sate of the sleep manager */ bool _deep_sleep_locked; #endif + /* Take over the physical SPI and apply our settings (thread safe) */ void aquire(void); + /* Current user of the SPI */ static SPI *_owner; + /* Used by lock and unlock for thread safety */ static SingletonPtr _mutex; + /* Size of the SPI frame */ int _bits; + /* Clock polairy and phase */ int _mode; + /* Clock frequency */ int _hz; + /* Default character used for NULL transfers */ char _write_fill; private: - /* Private acquire function without locking/unlocking - * Implemented in order to avoid duplicate locking and boost performance + /** Private acquire function without locking/unlocking. + * Implemented in order to avoid duplicate locking and boost performance. */ void _acquire(void); + +#endif //!defined(DOXYGEN_ONLY) }; } // namespace mbed