70 lines
2.1 KiB
C
70 lines
2.1 KiB
C
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/*
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Copyright (c) 2003, Thomas Kurschel
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Part of DDC driver
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I2C protocoll
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*/
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#ifndef _I2C_H
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#define _I2C_H
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#include <OS.h>
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// timing for i2c bus
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typedef struct i2c_timing {
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// general timing as defined by standard
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// (in microseconds for 100kHz/400kHz mode)
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int buf; // bus free between start and stop (4.7/1.3)
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int hd_sta; // hold time start condition (4.0/0.6)
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int low; // low period of clock (4.7/1.3)
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int high; // high period of clock (4.0/0.6)
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int su_sta; // setup time of repeated start condition (4.7/0.6)
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int hd_dat; // hold time data (5.0/- for CBUS, 0/0 for I2C)
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int su_dat; // setup time data (0.250/0.100)
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int r; // maximum raise time of clock and data signal (1.0/0.3)
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int f; // maximum fall time of clock and data signal (0.3/0.3)
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int su_sto; // setup time for stop condition (4.0/0.6)
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// clock stretching limits, not part of i2c standard
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int start_timeout; // max. delay of start condition
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int byte_timeout; // max. delay of first bit of byte
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int bit_timeout; // max. delay of one bit within a byte transmission
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int ack_start_timeout; // max. delay of acknowledge start
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// other timeouts, not part of i2c standard
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int ack_timeout; // timeout of waiting for acknowledge
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} i2c_timing;
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// set signals on bus
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typedef status_t (*i2c_set_signals)( void *cookie, int scl, int sda );
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// read signals from bus
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typedef status_t (*i2c_get_signals)( void *cookie, int *scl, int *sda );
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// i2c bus definition
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typedef struct i2c_bus {
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void *cookie; // user-defined cookie
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i2c_set_signals set_signals; // callback to set signals
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i2c_get_signals get_signals; // callback to detect signals
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} i2c_bus;
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// send and receive data via i2c bus
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status_t i2c_send_receive( const i2c_bus *bus, const i2c_timing *timing,
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int slave_address,
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const uint8 *write_buffer, size_t write_len,
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uint8 *read_buffer, size_t read_len );
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// fill <timing> with standard 100kHz bus timing
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void i2c_get100k_timing( i2c_timing *timing );
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// fill <timing> with standard 400kHz bus timing
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// (as timing resolution is 1 microsecond, we cannot reach full speed!)
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void i2c_get400k_timing( i2c_timing *timing );
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#endif
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