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mbed-classic/api/SPI.h

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/* mbed Microcontroller Library
* Copyright (c) 2006-2015 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef MBED_SPI_H
#define MBED_SPI_H
#include "platform.h"
#if DEVICE_SPI
#include "spi_api.h"
#if DEVICE_SPI_ASYNCH
#include "CThunk.h"
#include "dma_api.h"
#include "CircularBuffer.h"
#include "FunctionPointer.h"
#include "Transaction.h"
#endif
namespace mbed {
/** 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
*
* Most SPI devices will also require Chip Select and Reset signals. These
* can be controlled using <DigitalOut> pins
*
* Example:
* @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
*
* // software ssel
* SPI device(p5, p6, p7); // mosi, miso, sclk
* DigitalOut cs(p8); // ssel
*
* int main() {
* // hardware ssel (where applicable)
* //int response = device.write(0xFF);
*
* // software ssel
* cs = 0;
* int response = device.write(0xFF);
* cs = 1;
* }
* @endcode
*/
class SPI {
public:
/** Create a SPI master connected to the specified pins
*
* mosi or miso can be specfied 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
*/
SPI(PinName mosi, PinName miso, PinName sclk, PinName ssel=NC);
/** Configure the data transmission format
*
* @param bits Number of bits per SPI frame (4 - 16)
* @param mode Clock polarity and phase mode (0 - 3)
*
* @code
* mode | POL PHA
* -----+--------
* 0 | 0 0
* 1 | 0 1
* 2 | 1 0
* 3 | 1 1
* @endcode
*/
void format(int bits, int mode = 0);
/** Set the spi bus clock frequency
*
* @param hz SCLK frequency in hz (default = 1MHz)
*/
void frequency(int hz = 1000000);
/** Write to the SPI Slave and return the response
*
* @param value Data to be sent to the SPI slave
*
* @returns
* Response from the SPI slave
*/
virtual int write(int value);
#if DEVICE_SPI_ASYNCH
/** Start non-blocking SPI transfer using 8bit buffers.
*
* @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 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
*/
template<typename Type>
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) {
if (spi_active(&_spi)) {
return queue_transfer(tx_buffer, tx_length, rx_buffer, rx_length, sizeof(Type)*8, callback, event);
}
start_transfer(tx_buffer, tx_length, rx_buffer, rx_length, sizeof(Type)*8, callback, event);
return 0;
}
/** Abort the on-going SPI transfer, and continue with transfer's in the queue if any.
*/
void abort_transfer();
/** Clear the transaction buffer
*/
void clear_transfer_buffer();
/** Clear the transaction buffer and abort on-going transfer.
*/
void abort_all_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
*/
int set_dma_usage(DMAUsage usage);
protected:
/** SPI IRQ handler
*
*/
void irq_handler_asynch(void);
/** Common transfer method
*
* @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 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
*/
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);
/**
*
* @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 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
*/
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
*
* @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 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
*/
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 TRANSACTION_QUEUE_SIZE_SPI
/** Start a new transaction
*
* @param data Transaction data
*/
void start_transaction(transaction_t *data);
/** Dequeue a transaction
*
*/
void dequeue_transaction();
static CircularBuffer<Transaction<SPI>, TRANSACTION_QUEUE_SIZE_SPI> _transaction_buffer;
#endif
#endif
public:
virtual ~SPI() {
}
protected:
spi_t _spi;
#if DEVICE_SPI_ASYNCH
CThunk<SPI> _irq;
event_callback_t _callback;
DMAUsage _usage;
#endif
void aquire(void);
static SPI *_owner;
int _bits;
int _mode;
int _hz;
};
} // namespace mbed
#endif
#endif