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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_I2C_SLAVE_H
#define MBED_I2C_SLAVE_H
#include "platform.h"
#if DEVICE_I2CSLAVE
#include "i2c_api.h"
namespace mbed {
/** An I2C Slave, used for communicating with an I2C Master device
*
* Example:
* @code
* // Simple I2C responder
* #include <mbed.h>
*
* I2CSlave slave(p9, p10);
*
* int main() {
* char buf[10];
* char msg[] = "Slave!";
*
* slave.address(0xA0);
* while (1) {
* int i = slave.receive();
* switch (i) {
* case I2CSlave::ReadAddressed:
* slave.write(msg, strlen(msg) + 1); // Includes null char
* break;
* case I2CSlave::WriteGeneral:
* slave.read(buf, 10);
* printf("Read G: %s\n", buf);
* break;
* case I2CSlave::WriteAddressed:
* slave.read(buf, 10);
* printf("Read A: %s\n", buf);
* break;
* }
* for(int i = 0; i < 10; i++) buf[i] = 0; // Clear buffer
* }
* }
* @endcode
*/
class I2CSlave {
public:
enum RxStatus {
NoData = 0,
ReadAddressed = 1,
WriteGeneral = 2,
WriteAddressed = 3
};
/** Create an I2C Slave interface, connected to the specified pins.
*
* @param sda I2C data line pin
* @param scl I2C clock line pin
*/
I2CSlave(PinName sda, PinName scl);
/** Set the frequency of the I2C interface
*
* @param hz The bus frequency in hertz
*/
void frequency(int hz);
/** Checks to see if this I2C Slave has been addressed.
*
* @returns
* A status indicating if the device has been addressed, and how
* - NoData - the slave has not been addressed
* - ReadAddressed - the master has requested a read from this slave
* - WriteAddressed - the master is writing to this slave
* - WriteGeneral - the master is writing to all slave
*/
int receive(void);
/** Read from an I2C master.
*
* @param data pointer to the byte array to read data in to
* @param length maximum number of bytes to read
*
* @returns
* 0 on success,
* non-0 otherwise
*/
int read(char *data, int length);
/** Read a single byte from an I2C master.
*
* @returns
* the byte read
*/
int read(void);
/** Write to an I2C master.
*
* @param data pointer to the byte array to be transmitted
* @param length the number of bytes to transmite
*
* @returns
* 0 on success,
* non-0 otherwise
*/
int write(const char *data, int length);
/** Write a single byte to an I2C master.
*
* @data the byte to write
*
* @returns
* '1' if an ACK was received,
* '0' otherwise
*/
int write(int data);
/** Sets the I2C slave address.
*
* @param address The address to set for the slave (ignoring the least
* signifcant bit). If set to 0, the slave will only respond to the
* general call address.
*/
void address(int address);
/** Reset the I2C slave back into the known ready receiving state.
*/
void stop(void);
protected:
i2c_t _i2c;
};
} // namespace mbed
#endif
#endif
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