1 /* 2 * Copyright 2003, Thomas Kurschel. All Rights Reserved. 3 * Distributed under the terms of the MIT License. 4 */ 5 #ifndef _I2C_H 6 #define _I2C_H 7 8 9 #include <OS.h> 10 11 12 // timing for i2c bus 13 typedef struct i2c_timing { 14 // general timing as defined by standard 15 // (in microseconds for 100kHz/400kHz mode) 16 int buf; // bus free between start and stop (4.7/1.3) 17 int hd_sta; // hold time start condition (4.0/0.6) 18 int low; // low period of clock (4.7/1.3) 19 int high; // high period of clock (4.0/0.6) 20 int su_sta; // setup time of repeated start condition (4.7/0.6) 21 int hd_dat; // hold time data (5.0/- for CBUS, 0/0 for I2C) 22 int su_dat; // setup time data (0.250/0.100) 23 int r; // maximum raise time of clock and data signal (1.0/0.3) 24 int f; // maximum fall time of clock and data signal (0.3/0.3) 25 int su_sto; // setup time for stop condition (4.0/0.6) 26 27 // clock stretching limits, not part of i2c standard 28 int start_timeout; // max. delay of start condition 29 int byte_timeout; // max. delay of first bit of byte 30 int bit_timeout; // max. delay of one bit within a byte transmission 31 int ack_start_timeout; // max. delay of acknowledge start 32 33 // other timeouts, not part of i2c standard 34 int ack_timeout; // timeout of waiting for acknowledge 35 } i2c_timing; 36 37 38 // set signals on bus 39 typedef status_t (*i2c_set_signals)(void *cookie, int clock, int data); 40 // read signals from bus 41 typedef status_t (*i2c_get_signals)(void *cookie, int *clock, int *data); 42 43 // i2c bus definition 44 typedef struct i2c_bus { 45 void *cookie; // user-defined cookie 46 i2c_timing timing; 47 i2c_set_signals set_signals; // callback to set signals 48 i2c_get_signals get_signals; // callback to detect signals 49 } i2c_bus; 50 51 52 #ifdef __cplusplus 53 extern "C" { 54 #endif 55 56 // send and receive data via i2c bus 57 status_t i2c_send_receive(const i2c_bus *bus, int slave_address, 58 const uint8 *writeBuffer, size_t writeLength, uint8 *readBuffer, 59 size_t readLength); 60 61 // fill <timing> with standard 100kHz bus timing 62 void i2c_get100k_timing(i2c_timing *timing); 63 64 // fill <timing> with standard 400kHz bus timing 65 // (as timing resolution is 1 microsecond, we cannot reach full speed!) 66 void i2c_get400k_timing(i2c_timing *timing); 67 68 #ifdef __cplusplus 69 } 70 #endif 71 72 #endif /* _I2C_H */ 73