1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
/****************************************************************************
*
* Copyright (c) 2006 Dave Hylands <dhylands@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Alternatively, this software may be distributed under the terms of BSD
* license.
*
* See README and COPYING for more details.
*
****************************************************************************/
/**
*
* @file i2c.h
*
* @brief Global definitions for interfacing with the AVR TWI (aka I2C)
* hardware
*
****************************************************************************/
/**
* @defgroup xxx Readable version of xxx.
*
* @brief Brief description of what xxx does.
*
* Longer description of what xxx does.
*
****************************************************************************/
#if !defined( I2C_H )
#define I2C_H /**< Include Guard */
/* ---- Include Files ---------------------------------------------------- */
#include <inttypes.h>
#if !defined( CONFIG_H )
# include "Config.h"
#endif
/**
* @addtogroup I2C
* @{
*/
/* ---- Constants and Types ---------------------------------------------- */
/**
* Error Codes
*/
#define I2C_ERROR_NONE 0 // No Error
#define I2C_ERROR_ADDR_NACK -1 // No response to SLA+R/W
#define I2C_ERROR_DATA_NACK -2 // NACK during data transmission
#define I2C_ERROR_ARBITRATION_LOST -3 // Lost arbitration
#define I2C_ERROR_BAD_LEN -4 // Length is wonky
#define I2C_ERROR_BAD_CRC -5 // CRC failed
#define I2C_ERROR_BUS_ERROR -6 // Someting weird on the i2c bus
typedef int8_t I2C_Error_t;
/**
* Since we're loosely following the SMBus spec, we restrict the amount
* of data in each transaction to 32 bytes.
*/
#define I2C_MAX_DATA_LEN 32
/**
* I2C_Addr_t can contain the address of any device on the bus. This
* module only supports 7 bit addressing.
*/
typedef uint8_t I2C_Addr_t;
/**
* The I2C_CRC macro can be used to remove all CRC support at compile time.
*/
#if CFG_I2C_USE_CRC
# define I2C_CRC(x) x
#else
# define I2C_CRC(x)
#endif
/**
* I2C_Data_t encapsulates the data being read or written on the i2c bus.
* This module follows the SMBus spec, whihch specifies a maximum payload
* of 32 bytes.
*/
typedef struct
{
#if CFG_I2C_USE_CRC
uint8_t m_crc;
#endif
// For reads, m_len is the number of bytes actually read (doesn't include
// the CRC - if present). If a block transfer was performed which has a
// length byte, this length will include the length byte.
uint8_t m_len;
// Note: Under SMBus, a block write can consist of a command, a length,
// 32 bytes of payload, and a CRC.
//
// A read response can consist of a length, 32 bytes of data, and a CRC.
uint8_t m_data[ I2C_MAX_DATA_LEN + 2]; // +1 for the command, +1 for length
} I2C_Data_t;
/* ---- Variable Externs ------------------------------------------------- */
/**
* Description of variable.
*/
/* ---- Function Prototypes ---------------------------------------------- */
/*
* Just include prototypes here. Put full descriptions in the .c files.
*/
/** @} */
#endif /* I2C_H */
|
