mbed-os/libraries/mbed/api/SPI.h

114 lines
2.6 KiB
C++

/* mbed Microcontroller Library
* Copyright (c) 2006-2013 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"
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"
*
* SPI device(p5, p6, p7); // mosi, miso, sclk
*
* int main() {
* int response = device.write(0xFF);
* }
* @endcode
*/
class SPI {
public:
/** Create a SPI master connected to the specified pins
*
* Pin Options:
* (5, 6, 7) or (11, 12, 13)
*
* 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
*/
SPI(PinName mosi, PinName miso, PinName sclk, PinName _unused=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);
public:
virtual ~SPI() {
}
protected:
spi_t _spi;
void aquire(void);
static SPI *_owner;
int _bits;
int _mode;
int _hz;
};
} // namespace mbed
#endif
#endif