Steve Martin / libdrv_SoftI2C

Fork of SoftI2C. Added clock stretching support.

Fork of SoftI2C by Erik -

SoftI2C.h@0:fee70b6fe0e9, 2016-11-22 (annotated)

Committer:
Sissors
Date:
Tue Nov 22 20:45:35 2016 +0000
Revision:
0:fee70b6fe0e9
Initial version

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Sissors 0:fee70b6fe0e9 1 #include "mbed.h"
Sissors 0:fee70b6fe0e9 2
Sissors 0:fee70b6fe0e9 3 #ifndef SOFTI2C_H
Sissors 0:fee70b6fe0e9 4 #define SOFTI2C_H
Sissors 0:fee70b6fe0e9 5
Sissors 0:fee70b6fe0e9 6 /**
Sissors 0:fee70b6fe0e9 7 * A software I2C class in case you run out of hardware I2C pins or cannot use
Sissors 0:fee70b6fe0e9 8 * those for another reason.
Sissors 0:fee70b6fe0e9 9 *
Sissors 0:fee70b6fe0e9 10 * The class is a drop-in replacement of the classic mbed I2C class: include
Sissors 0:fee70b6fe0e9 11 * this file in your program, replace I2C with SoftI2C when creating the object
Sissors 0:fee70b6fe0e9 12 * and it should work properly without other modifications.
Sissors 0:fee70b6fe0e9 13 */
Sissors 0:fee70b6fe0e9 14 class SoftI2C {
Sissors 0:fee70b6fe0e9 15 public:
Sissors 0:fee70b6fe0e9 16 /**
Sissors 0:fee70b6fe0e9 17 * Create an software I2C Master interface, connected to the specified pins
Sissors 0:fee70b6fe0e9 18 *
Sissors 0:fee70b6fe0e9 19 * @param sda I2C data pin
Sissors 0:fee70b6fe0e9 20 * @param scl I2C clock pin
Sissors 0:fee70b6fe0e9 21 */
Sissors 0:fee70b6fe0e9 22 SoftI2C(PinName sda, PinName scl);
Sissors 0:fee70b6fe0e9 23
Sissors 0:fee70b6fe0e9 24 /**
Sissors 0:fee70b6fe0e9 25 * Set the frequency of the I2C interface.
Sissors 0:fee70b6fe0e9 26 *
Sissors 0:fee70b6fe0e9 27 * Note that the delay of the DigitalInOuts is not compensated: the real
Sissors 0:fee70b6fe0e9 28 * frequency will be lower than the one set. However since I2C is a
Sissors 0:fee70b6fe0e9 29 * synchronous protocol this shouldn't affect functionality
Sissors 0:fee70b6fe0e9 30 *
Sissors 0:fee70b6fe0e9 31 * @param hz The bus frequency in hertz
Sissors 0:fee70b6fe0e9 32 */
Sissors 0:fee70b6fe0e9 33 void frequency(int hz);
Sissors 0:fee70b6fe0e9 34
Sissors 0:fee70b6fe0e9 35 /**
Sissors 0:fee70b6fe0e9 36 * Read from an I2C slave.
Sissors 0:fee70b6fe0e9 37 *
Sissors 0:fee70b6fe0e9 38 * Performs a complete read transaction. The bottom bit of the address is forced to 1 to indicate a read.
Sissors 0:fee70b6fe0e9 39 *
Sissors 0:fee70b6fe0e9 40 * @param address 8-bit I2C slave address [ addr | 1 ]
Sissors 0:fee70b6fe0e9 41 * @param Pointer to the byte-array data to read to
Sissors 0:fee70b6fe0e9 42 * @param length Number of bytes to read
Sissors 0:fee70b6fe0e9 43 * @param repeated Repeated start, true - do not send stop at end
Sissors 0:fee70b6fe0e9 44 * @return 0 on success (ack), non-0 on failure (nack)
Sissors 0:fee70b6fe0e9 45 */
Sissors 0:fee70b6fe0e9 46 int read(int address, char *data, int length, bool repeated=false);
Sissors 0:fee70b6fe0e9 47
Sissors 0:fee70b6fe0e9 48 /**
Sissors 0:fee70b6fe0e9 49 * Read a single byte from the I2C bus
Sissors 0:fee70b6fe0e9 50 *
Sissors 0:fee70b6fe0e9 51 * @param ack indicates if the byte is to be acknowledged (1 = acknowledge)
Sissors 0:fee70b6fe0e9 52 * @return the byte read
Sissors 0:fee70b6fe0e9 53 */
Sissors 0:fee70b6fe0e9 54 int read(int ack);
Sissors 0:fee70b6fe0e9 55
Sissors 0:fee70b6fe0e9 56 /**
Sissors 0:fee70b6fe0e9 57 * Write to an I2C slave.
Sissors 0:fee70b6fe0e9 58 *
Sissors 0:fee70b6fe0e9 59 * Performs a complete write transaction. The bottom bit of the address is forced to 0 to indicate a write.
Sissors 0:fee70b6fe0e9 60 *
Sissors 0:fee70b6fe0e9 61 * @param address 8-bit I2C slave address [ addr | 0 ]
Sissors 0:fee70b6fe0e9 62 * @param Pointer to the byte-array data to send
Sissors 0:fee70b6fe0e9 63 * @param length Number of bytes to send
Sissors 0:fee70b6fe0e9 64 * @param repeated Repeated start, true - do not send stop at end
Sissors 0:fee70b6fe0e9 65 * @return 0 on success (ack), non-0 on failure (nack)
Sissors 0:fee70b6fe0e9 66 */
Sissors 0:fee70b6fe0e9 67 int write(int address, const char *data, int length, bool repeated=false);
Sissors 0:fee70b6fe0e9 68
Sissors 0:fee70b6fe0e9 69 /**
Sissors 0:fee70b6fe0e9 70 * Write single byte out on the I2C bus
Sissors 0:fee70b6fe0e9 71 *
Sissors 0:fee70b6fe0e9 72 * @param data data to write on the bus
Sissors 0:fee70b6fe0e9 73 * @return '1' if an ACK is received, '0' otherwise
Sissors 0:fee70b6fe0e9 74 */
Sissors 0:fee70b6fe0e9 75 int write(int data);
Sissors 0:fee70b6fe0e9 76
Sissors 0:fee70b6fe0e9 77 /**
Sissors 0:fee70b6fe0e9 78 * Create a (re-)start condition on the I2C bus
Sissors 0:fee70b6fe0e9 79 */
Sissors 0:fee70b6fe0e9 80 void start(void);
Sissors 0:fee70b6fe0e9 81
Sissors 0:fee70b6fe0e9 82 /**
Sissors 0:fee70b6fe0e9 83 * Create a stop condition on the I2C bus
Sissors 0:fee70b6fe0e9 84 */
Sissors 0:fee70b6fe0e9 85 void stop(void);
Sissors 0:fee70b6fe0e9 86
Sissors 0:fee70b6fe0e9 87 protected:
Sissors 0:fee70b6fe0e9 88 DigitalInOut _sda;
Sissors 0:fee70b6fe0e9 89 DigitalInOut _scl;
Sissors 0:fee70b6fe0e9 90 int delay_us;
Sissors 0:fee70b6fe0e9 91 bool active;
Sissors 0:fee70b6fe0e9 92 };
Sissors 0:fee70b6fe0e9 93
Sissors 0:fee70b6fe0e9 94
Sissors 0:fee70b6fe0e9 95 #endif