blob: f22f7c5d8629f1eb89533496ad660b1c0f93dd36 (
plain)
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
|
#include "knob_v2.h"
bool knob_prev_a = false;
static knob_report_t knob_report = {.dir = 0, .phase = 0};
void knob_init(void) {
// I use pins D1 (ISR1) & D4 for a knob.
// Set pin mode for D4 as input.
DDRD &= ~(0UL << ENCODER_PIN_2);
// Enable internal pull-up for D4.
// This is done by "writing" 1 to a pin that has its mode set to input.
PORTD |= (1 << ENCODER_PIN_2);
// Enable interrupt for D1
// For more info on the below flags see this awesome section 11.1 (pages 89-90) here:
// https://cdn-shop.adafruit.com/datasheets/atmel-7766-8-bit-avr-atmega16u4-32u4_datasheet.pdf
// Set pin mode & pull-up.
DDRD &= ~(0UL << ENCODER_PIN_1);
PORTD |= (1UL << ENCODER_PIN_1);
// INT: 33221100
EICRA |= 0b00010000; // 0b01 - any edge
// INT: 6 3210
EIMSK |= 0b00000100;
}
ISR(ENCODER_INT) {
bool a = PIND & (1 << ENCODER_PIN_1);
if (knob_prev_a != a) {
// "A" channel has REALLY changed.
knob_report.phase = a;
knob_prev_a = a;
bool b = PIND & (1 << ENCODER_PIN_2);
if (a == b) {
// Halfway through CCW rotation (A == B)
//
// +---YOU ARE HERE (A=1, B=1)
// | +---OR HERE (A=0, B=0)
// | |
// v v
// A: _____/^^^^^\__
// B: __/^^^^^\_____
knob_report.dir++;
} else {
// Halfway through CW rotation (A != B)
//
// +---YOU ARE HERE (A=1, B=0)
// | +---OR HERE (A=0, B=1)
// | |
// v v
// A: _____/^^^^^\_____
// B: ________/^^^^^\__
knob_report.dir--;
}
}
}
knob_report_t knob_report_read(void) {
// Return knob report.
return knob_report;
}
void knob_report_reset(void) {
// Call this ASAP once you've processed the previous knob report.
// TODO: This should probably be called within `knob_report_read`.
knob_report.dir = 0;
knob_report.phase = 0;
}
|
