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
|
/*
# WS2812 Library for libopencm3
Please mind these restrictions:
- Only usable with libopencm3
- Newer versions of libopencm3 may be not compatibel (libopencm3 api is not stable yet)
- Just usable with a clock frequency of 72 MHz
- You have to setup the clock and gpio yourself
*/
#include "ws2812.h"
#define NUMBER_NOPS_RESET 1080 // > 50 µs --> 60 µs (to be sure) = 4320 cycles @ 72 MHz = 1080 nops
#define NUMBER_NOPS_LONG 16 // 0.9 µs = 64.8 cycles @ 72 MHz = 16.2 nops --> 11.1 ns timing error
#define NUMBER_NOPS_SHORT 6 // 0.35 µs = 25.2 cycles @ 72 MHz = 6.3 nops --> 16.7 ns timing error
void ws2812_init(WS2812_ARRAY *control_struct, uint32_t port, uint16_t pin, uint8_t *buffer_ptr, uint32_t array_length)
{
control_struct->gpio_port = port;
control_struct->gpio_pin = pin;
control_struct->array_buffer = buffer_ptr;
control_struct->array_length = array_length;
ws2812_clear_buffer(control_struct);
ws2812_send_reset(control_struct);
}
void ws2812_send_reset(WS2812_ARRAY *control_struct)
{
gpio_clear(control_struct->gpio_port, control_struct->gpio_pin);
for (int i = 0; i < NUMBER_NOPS_RESET; i++) {
__asm__("nop");
}
}
void ws2812_send_zero(WS2812_ARRAY *control_struct)
{
gpio_set(control_struct->gpio_port, control_struct->gpio_pin);
for (int i = 0; i < NUMBER_NOPS_SHORT; i++) {
__asm__("nop");
}
gpio_clear(control_struct->gpio_port, control_struct->gpio_pin);
for (int i = 0; i < NUMBER_NOPS_LONG; i++) {
__asm__("nop");
}
}
void ws2812_send_one(WS2812_ARRAY *control_struct)
{
gpio_set(control_struct->gpio_port, control_struct->gpio_pin);
for (int i = 0; i < NUMBER_NOPS_LONG; i++) {
__asm__("nop");
}
gpio_clear(control_struct->gpio_port, control_struct->gpio_pin);
for (int i = 0; i < NUMBER_NOPS_SHORT; i++) {
__asm__("nop");
}
}
void ws2812_send_byte(WS2812_ARRAY *control_struct, uint8_t data)
{
for (int i=7; i>=0; i--){
if ( (data >> i) & 0x01 ){
ws2812_send_one(control_struct);
}
else {
ws2812_send_zero(control_struct);
}
}
}
void ws2812_send_led(WS2812_ARRAY *control_struct, uint8_t red, uint8_t green, uint8_t blue)
{
ws2812_send_byte(control_struct, green);
ws2812_send_byte(control_struct, red);
ws2812_send_byte(control_struct, blue);
}
void ws2812_write_leds(WS2812_ARRAY *control_struct)
{
for(uint32_t i=0; i<(control_struct->array_length); i++){
ws2812_send_led(
control_struct,
control_struct->array_buffer[i * WS2812_NUMBER_OF_COLORS + 0], // red
control_struct->array_buffer[i * WS2812_NUMBER_OF_COLORS + 1], // green
control_struct->array_buffer[i * WS2812_NUMBER_OF_COLORS + 2] // blue
);
}
ws2812_send_reset(control_struct);
}
void ws2812_set_array_led(WS2812_ARRAY *control_struct, uint32_t index, uint8_t red, uint8_t green, uint8_t blue)
{
control_struct->array_buffer[index * WS2812_NUMBER_OF_COLORS + 0] = red;
control_struct->array_buffer[index * WS2812_NUMBER_OF_COLORS + 1] = green;
control_struct->array_buffer[index * WS2812_NUMBER_OF_COLORS + 2] = blue;
}
void ws2812_clear_buffer(WS2812_ARRAY *control_struct)
{
for (uint32_t i=0; i<control_struct->array_length; i++){
ws2812_set_array_led(control_struct, i, 0, 0, 0);
}
}
|
