mirror of https://github.com/ARMmbed/mbed-os.git
310 lines
9.9 KiB
C++
310 lines
9.9 KiB
C++
/* mbed Microcontroller Library
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* Copyright (c) 2006-2015 ARM Limited
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*
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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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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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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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#ifndef MBED_SPI_H
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#define MBED_SPI_H
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#include "platform/platform.h"
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#if defined (DEVICE_SPI) || defined(DOXYGEN_ONLY)
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#include "platform/PlatformMutex.h"
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#include "hal/spi_api.h"
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#include "platform/SingletonPtr.h"
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#include "platform/NonCopyable.h"
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#if DEVICE_SPI_ASYNCH
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#include "platform/CThunk.h"
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#include "hal/dma_api.h"
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#include "platform/CircularBuffer.h"
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#include "platform/FunctionPointer.h"
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#include "platform/Transaction.h"
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#endif
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namespace mbed {
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/** \addtogroup drivers */
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/** A SPI Master, used for communicating with SPI slave devices
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*
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* The default format is set to 8-bits, mode 0, and a clock frequency of 1MHz
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*
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* Most SPI devices will also require Chip Select and Reset signals. These
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* can be controlled using DigitalOut pins
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*
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* @note Synchronization level: Thread safe
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*
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* Example:
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* @code
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* // Send a byte to a SPI slave, and record the response
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*
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* #include "mbed.h"
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*
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* // hardware ssel (where applicable)
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* //SPI device(p5, p6, p7, p8); // mosi, miso, sclk, ssel
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*
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* // software ssel
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* SPI device(p5, p6, p7); // mosi, miso, sclk
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* DigitalOut cs(p8); // ssel
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*
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* int main() {
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* // hardware ssel (where applicable)
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* //int response = device.write(0xFF);
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*
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* device.lock();
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* // software ssel
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* cs = 0;
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* int response = device.write(0xFF);
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* cs = 1;
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* device.unlock();
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*
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* }
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* @endcode
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* @ingroup drivers
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*/
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class SPI : private NonCopyable<SPI> {
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public:
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/** Create a SPI master connected to the specified pins
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*
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* mosi or miso can be specified as NC if not used
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*
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* @param mosi SPI Master Out, Slave In pin
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* @param miso SPI Master In, Slave Out pin
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* @param sclk SPI Clock pin
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* @param ssel SPI chip select pin
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*/
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SPI(PinName mosi, PinName miso, PinName sclk, PinName ssel = NC);
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/** Configure the data transmission format
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*
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* @param bits Number of bits per SPI frame (4 - 16)
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* @param mode Clock polarity and phase mode (0 - 3)
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*
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* @code
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* mode | POL PHA
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* -----+--------
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* 0 | 0 0
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* 1 | 0 1
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* 2 | 1 0
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* 3 | 1 1
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* @endcode
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*/
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void format(int bits, int mode = 0);
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/** Set the spi bus clock frequency
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*
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* @param hz SCLK frequency in hz (default = 1MHz)
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*/
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void frequency(int hz = 1000000);
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/** Write to the SPI Slave and return the response
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*
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* @param value Data to be sent to the SPI slave
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*
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* @returns
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* Response from the SPI slave
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*/
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virtual int write(int value);
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/** Write to the SPI Slave and obtain the response
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*
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* The total number of bytes sent and received will be the maximum of
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* tx_length and rx_length. The bytes written will be padded with the
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* value 0xff.
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*
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* @param tx_buffer Pointer to the byte-array of data to write to the device
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* @param tx_length Number of bytes to write, may be zero
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* @param rx_buffer Pointer to the byte-array of data to read from the device
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* @param rx_length Number of bytes to read, may be zero
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* @returns
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* The number of bytes written and read from the device. This is
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* maximum of tx_length and rx_length.
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*/
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virtual int write(const char *tx_buffer, int tx_length, char *rx_buffer, int rx_length);
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/** Acquire exclusive access to this SPI bus
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*/
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virtual void lock(void);
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/** Release exclusive access to this SPI bus
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*/
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virtual void unlock(void);
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/** Set default write data
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* SPI requires the master to send some data during a read operation.
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* Different devices may require different default byte values.
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* For example: A SD Card requires default bytes to be 0xFF.
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*
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* @param data Default character to be transmitted while read operation
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*/
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void set_default_write_value(char data);
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#if DEVICE_SPI_ASYNCH
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/** Start non-blocking SPI transfer using 8bit buffers.
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*
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* This function locks the deep sleep until any event has occurred
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*
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* @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
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* the default SPI value is sent
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* @param tx_length The length of TX buffer in bytes
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* @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
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* received data are ignored
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* @param rx_length The length of RX buffer in bytes
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* @param callback The event callback function
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* @param event The logical OR of events to modify. Look at spi hal header file for SPI events.
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* @return Zero if the transfer has started, or -1 if SPI peripheral is busy
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*/
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template<typename Type>
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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)
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{
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if (spi_active(&_spi)) {
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return queue_transfer(tx_buffer, tx_length, rx_buffer, rx_length, sizeof(Type) * 8, callback, event);
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}
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start_transfer(tx_buffer, tx_length, rx_buffer, rx_length, sizeof(Type) * 8, callback, event);
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return 0;
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}
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/** Abort the on-going SPI transfer, and continue with transfer's in the queue if any.
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*/
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void abort_transfer();
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/** Clear the transaction buffer
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*/
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void clear_transfer_buffer();
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/** Clear the transaction buffer and abort on-going transfer.
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*/
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void abort_all_transfers();
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/** Configure DMA usage suggestion for non-blocking transfers
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*
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* @param usage The usage DMA hint for peripheral
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* @return Zero if the usage was set, -1 if a transaction is on-going
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*/
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int set_dma_usage(DMAUsage usage);
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protected:
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/** SPI IRQ handler
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*
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*/
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void irq_handler_asynch(void);
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/** Common transfer method
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*
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* @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
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* the default SPI value is sent
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* @param tx_length The length of TX buffer in bytes
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* @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
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* received data are ignored
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* @param rx_length The length of RX buffer in bytes
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* @param bit_width The buffers element width
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* @param callback The event callback function
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* @param event The logical OR of events to modify
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* @return Zero if the transfer has started or was added to the queue, or -1 if SPI peripheral is busy/buffer is full
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*/
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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);
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/**
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*
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* @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
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* the default SPI value is sent
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* @param tx_length The length of TX buffer in bytes
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* @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
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* received data are ignored
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* @param rx_length The length of RX buffer in bytes
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* @param bit_width The buffers element width
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* @param callback The event callback function
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* @param event The logical OR of events to modify
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* @return Zero if a transfer was added to the queue, or -1 if the queue is full
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*/
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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);
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/** Configures a callback, spi peripheral and initiate a new transfer
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*
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* @param tx_buffer The TX buffer with data to be transfered. If NULL is passed,
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* the default SPI value is sent
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* @param tx_length The length of TX buffer in bytes
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* @param rx_buffer The RX buffer which is used for received data. If NULL is passed,
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* received data are ignored
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* @param rx_length The length of RX buffer in bytes
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* @param bit_width The buffers element width
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* @param callback The event callback function
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* @param event The logical OR of events to modify
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*/
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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);
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private:
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/** Lock deep sleep only if it is not yet locked */
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void lock_deep_sleep();
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/** Unlock deep sleep in case it is locked */
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void unlock_deep_sleep();
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#if TRANSACTION_QUEUE_SIZE_SPI
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/** Start a new transaction
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*
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* @param data Transaction data
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*/
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void start_transaction(transaction_t *data);
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/** Dequeue a transaction
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*
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*/
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void dequeue_transaction();
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static CircularBuffer<Transaction<SPI>, TRANSACTION_QUEUE_SIZE_SPI> _transaction_buffer;
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#endif
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#endif
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public:
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virtual ~SPI()
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{
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}
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protected:
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spi_t _spi;
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#if DEVICE_SPI_ASYNCH
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CThunk<SPI> _irq;
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event_callback_t _callback;
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DMAUsage _usage;
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bool _deep_sleep_locked;
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#endif
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void aquire(void);
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static SPI *_owner;
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static SingletonPtr<PlatformMutex> _mutex;
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int _bits;
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int _mode;
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int _hz;
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char _write_fill;
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private:
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/* Private acquire function without locking/unlocking
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* Implemented in order to avoid duplicate locking and boost performance
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*/
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void _acquire(void);
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};
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} // namespace mbed
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#endif
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#endif
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