1 CAN Message Utilities for C
2 ===========================
4 This is a C library with functions to help encode and decode Controller Area
5 Network (CAN) message payloads. Some of the bitfield functions may be useful for
8 The header files contain complete function documentation, but to get you
9 started, here are examples using the API:
11 ## Bitfield Manipulation
13 uint8_t data[4] = {0x12, 0x34, 0x56, 0x78};
14 uint8_t result = get_byte(data, sizeof(data), 0);
15 uint8_t result = get_nibble(data, sizeof(data), 0);
16 fail_unless(copy_bits_right_aligned(data, 4, 4, 12, result, 4));
18 ## 8 Byte Bitfield Decoding
20 uint64_t data = 0x8000000000000000;
21 uint64_t result = get_bit_field(data, 0, 1, false);
24 data = 0x0402574d555a0401;
25 result = get_bit_field(data, 16, 32, false);
26 // result = 0x574d555a;
28 data = 0x00000000F34DFCFF;
29 result = nth_byte(data, 0);
32 result = nth_byte(data, 4);
35 ## 8 Byte Bitfield Encoding
38 fail_unless(set_bit_field(&data, 1, 0, 1));
39 uint64_t result = get_bit_field(data, 0, 1, false);
40 ck_assert_int_eq(result, 0x1);
42 TODO setting bit fields is just copying
44 ## CAN Signal Encoding
46 The library supports encoding floating point CAN signals as well as booleans
47 into a uint64_t payload.
49 uint64_t payload = bitfield_encode_float(1, 1, 3, 1, 0)
50 // payload == 0x1000000000000000
52 payload = bitfield_encode_bool(true, 1, 3);
53 // payload == 0x1000000000000000
55 ## CAN Signal Decoding
57 The library supports parsing floating point CAN signals as well as booleans.
59 uint64_t payload = 0xeb00000000000000;
60 float float_result = bitfield_parse_float(payload,
62 4, // width of the signal's field
63 1001.0, // transformation factor for the signal value
64 -30000.0); // transformation offset for the signal value
65 // float_result == -19990.0
67 bool bool_result = bitfield_parse_bool(payload,
69 1, // width of the signal's field
70 1.0, // transformation factor for the signal value
71 0); // transformation offset for the signal value
72 // bool_result == true
76 The library includes a test suite that uses the `check` C unit test library.
82 Chris Peplin cpeplin@ford.com
86 Copyright (c) 2013 Ford Motor Company
88 Licensed under the BSD license.