microbit-dal/inc/MicroBitI2C.h

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#ifndef MICROBIT_I2C_H
#define MICROBIT_I2C_H
#include "mbed.h"
#define MICROBIT_I2C_MAX_RETRIES 9
/**
* Class definition for MicroBitI2C.
*
* Presents a wrapped mbed call to capture failed I2C operations caused by a known silicon bug in the nrf51822.
* Attempts to automatically reset and restart the I2C hardware if this case is detected.
*
* For reference see PAN56 in:
*
* https://www.nordicsemi.com/eng/nordic/Products/nRF51822/PAN-nRF51822/24634
*
* v2.0 through to v2.4
*/
class MicroBitI2C : public I2C
{
uint8_t retries;
public:
/**
* Constructor.
* Create an instance of i2c
* @param sda the Pin to be used for SDA
* @param scl the Pin to be used for SCL
* Example:
* @code
* MicroBitI2C i2c(MICROBIT_PIN_SDA, MICROBIT_PIN_SCL);
* @endcode
* @note this should prevent i2c lockups as well.
*/
MicroBitI2C(PinName sda, PinName scl);
/**
* Performs a complete read transaction. The bottom bit of the address is forced to 1 to indicate a read.
*
* @address 8-bit I2C slave address [ addr | 1 ]
* @data Pointer to the byte-array to read data in to
* @length Number of bytes to read
* @repeated Repeated start, true - don't send stop at end.
*
* @return MICROBIT_OK on success, MICROBIT_I2C_ERROR if an unresolved read failure is detected.
*/
int read(int address, char *data, int length, bool repeated = false);
/**
* Performs a complete write transaction. The bottom bit of the address is forced to 0 to indicate a write.
*
* @address 8-bit I2C slave address [ addr | 0 ]
* @data Pointer to the byte-arraycontaining the data to write
* @length Number of bytes to write
* @repeated Repeated start, true - don't send stop at end.
*
* @return MICROBIT_OK on success, MICROBIT_I2C_ERROR if an unresolved write failure is detected.
*/
int write(int address, const char *data, int length, bool repeated = false);
};
#endif