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
|
/*
* MIT License
*
* Copyright (c) 2023 Gabor L Ugray
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef CHIRPY_TX_H
#define CHIRPY_TX_H
/** @brief Calculates the CRC of a byte sequence.
*/
uint8_t chirpy_crc8(const uint8_t *addr, uint16_t len);
/** @brief Updates a CRC value with the next byte of input.
*/
uint8_t chirpy_update_crc8(uint8_t next_byte, uint8_t crc);
/** @brief Function to return next byte to be encoded.
* @param next_byte Pointer where implementor must write next byte (if available).
* @return 1 if there is a next byte, or 0 if no more data to encode.
*/
typedef uint8_t (*chirpy_get_next_byte_t)(uint8_t *next_byte);
#define CHIRPY_TONE_BUF_SIZE 16
// Holds state used by the encoder. Do not manipulate directly.
typedef struct {
uint8_t tone_buf[CHIRPY_TONE_BUF_SIZE];
uint8_t tone_pos;
uint8_t tone_count;
uint8_t block_len;
uint8_t block_size;
uint8_t crc;
uint16_t bits;
uint8_t bit_count;
chirpy_get_next_byte_t get_next_byte;
} chirpy_encoder_state_t;
/** @brief Iniitializes the encoder state to be used during the transmission.
* @param ces Pointer to encoder state object to be initialized.
* @param get_next_byte Pointer to function that the encoder will call to fetch data byte by byte.
*/
void chirpy_init_encoder(chirpy_encoder_state_t *ces, chirpy_get_next_byte_t get_next_byte);
/** @brief Returns the next tone to be transmitted.
* @details This function will call the get_next_byte function stored in the encoder state to
* retrieve the next byte to be transmitted as needed. As a single byte is encoded as several tones,
* and because the transmission also includes periodic CRC values, not every call to this function
* will result in a callback for the next data byte.
* @param ced Pointer to the encoder state object.
* @return A tone index from 0 to N (where N is the largest tone index), or 255 if the transmission is over.
*/
uint8_t chirpy_get_next_tone(chirpy_encoder_state_t *ces);
/** @brief Returns the period value for buzzing out a tone.
* @param tone The tone index, 0 thru 8.
* @return The period for the tone's frequency, i.e., 1_000_000 / freq.
*/
uint16_t chirpy_get_tone_period(uint8_t tone);
/** @brief Typedef for a tick handler function.
*/
typedef void (*chirpy_tick_fun_t)(void *context);
/** @brief Creature-comfort struct for use in your chirping code.
* @details The idea is to handle a tick that happens 64 times per second at the outermost level.
* To get to the desired ~20 tones per second, increment a counter and call the actual
* transmission ticker when tick_counter reaches tick_compare, with a compare value of 3.
* seq_pos is for use by the transmission function to keep track of where it is in the data.
* The current transmission function is stored in tick_fun. You can have multiple phases
* by switching to a different function. E.g., intro countdown first, followed by data chirping.
*/
typedef struct {
uint8_t tick_count;
uint8_t tick_compare;
uint16_t seq_pos;
chirpy_tick_fun_t tick_fun;
} chirpy_tick_state_t;
#endif
|
