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mbed-classic/api/SPISlave.h

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/* 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_SPISLAVE_H
#define MBED_SPISLAVE_H
#include "platform.h"
#if DEVICE_SPISLAVE
#include "spi_api.h"
namespace mbed {
/** A SPI slave, used for communicating with a SPI Master device
*
* The default format is set to 8-bits, mode 0, and a clock frequency of 1MHz
*
* Example:
* @code
* // Reply to a SPI master as slave
*
* #include "mbed.h"
*
* SPISlave device(p5, p6, p7, p8); // mosi, miso, sclk, ssel
*
* int main() {
* device.reply(0x00); // Prime SPI with first reply
* while(1) {
* if(device.receive()) {
* int v = device.read(); // Read byte from master
* v = (v + 1) % 0x100; // Add one to it, modulo 256
* device.reply(v); // Make this the next reply
* }
* }
* }
* @endcode
*/
class SPISlave {
public:
/** Create a SPI slave 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
*/
SPISlave(PinName mosi, PinName miso, PinName sclk, PinName ssel);
/** 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);
/** Polls the SPI to see if data has been received
*
* @returns
* 0 if no data,
* 1 otherwise
*/
int receive(void);
/** Retrieve data from receive buffer as slave
*
* @returns
* the data in the receive buffer
*/
int read(void);
/** Fill the transmission buffer with the value to be written out
* as slave on the next received message from the master.
*
* @param value the data to be transmitted next
*/
void reply(int value);
protected:
spi_t _spi;
int _bits;
int _mode;
int _hz;
};
} // namespace mbed
#endif
#endif