-
Notifications
You must be signed in to change notification settings - Fork 1
/
app-encoder.c
102 lines (81 loc) · 2.73 KB
/
app-encoder.c
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
/*
* MPG-Nano - Firmware and UCCNC plugin for Arduino Nano based serial-over-USB
* interface for modified 4-axis Chinese MPG pendant.
*
* https://github.com/mattbucknall/mpg-nano
*
* Copyright (c) 2021 Matthew T. Bucknall
*
* 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, ARISIN
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#include <avr/interrupt.h>
#include <avr/io.h>
#include "app-io.h"
static int16_t m_delta;
static uint8_t m_prev_bits;
void app_encoder_reset(void) {
// clear delta counter
m_delta = 0;
}
int16_t app_encoder_delta(void) {
int16_t delta;
// capture and clear delta counter
delta = m_delta;
m_delta = 0;
return delta;
}
void app_encoder_loop(void) {
static uint8_t phase;
static uint8_t hyst;
// not using PROGMEM because this LUT is small and better off in RAM
static const int8_t LUT[16] = {
0, 1, -1, 0,
-1, 0, 0, 1,
1, 0, 0, -1,
0, -1, 1, 0
};
// capture encoder input states
uint8_t bits = PINC;
int8_t dir;
// decode direction of quadrature transition
bits = (bits & (1 << APP_IO_C_ENC_AP)) | ((bits & (1 << APP_IO_C_ENC_BP)) >> 1);
dir = LUT[bits | m_prev_bits];
m_prev_bits = bits << 2;
// update phase
phase = (phase + dir) & 3;
// apply hysteresis and update delta
if ( phase == 0 && !hyst ) {
if ( dir > 0 ) {
m_delta++;
} else if ( dir < 0 ) {
m_delta--;
}
hyst = 1;
}
else if ( phase == 2 ) {
hyst = 0;
}
}
void app_encoder_init(void) {
uint8_t bits;
// capture initial state
bits = PINC;
m_prev_bits = (bits & (1 << APP_IO_C_ENC_AP)) | ((bits & (1 << APP_IO_C_ENC_BP)) >> 1);
m_prev_bits = m_prev_bits << 2;
}