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
|
// Support for bit-banging commands to WS2812 type "neopixel" LEDs
//
// Copyright (C) 2019 Kevin O'Connor <kevin@koconnor.net>
//
// This file may be distributed under the terms of the GNU GPLv3 license.
#include "autoconf.h" // CONFIG_MACH_AVR
#include "board/gpio.h" // gpio_out_write
#include "board/irq.h" // irq_poll
#include "board/misc.h" // timer_read_time
#include "basecmd.h" // oid_alloc
#include "command.h" // DECL_COMMAND
struct neopixel_s {
struct gpio_out pin;
uint32_t last_req_time;
};
void
command_config_neopixel(uint32_t *args)
{
struct gpio_out pin = gpio_out_setup(args[1], 0);
struct neopixel_s *n = oid_alloc(args[0], command_config_neopixel
, sizeof(*n));
n->pin = pin;
}
#if !CONFIG_MACH_AVR
DECL_COMMAND(command_config_neopixel, "config_neopixel oid=%c pin=%u");
#endif
uint32_t
timer_from_ns(uint32_t ns)
{
return timer_from_us(ns * 1000) / 1000000;
}
static int
send_data(struct neopixel_s *n, uint8_t *data, uint_fast8_t data_len)
{
// Make sure at least 50us has passed since last request
uint32_t last_req_time = n->last_req_time, cur = timer_read_time();
while (cur - last_req_time < timer_from_us(50)) {
irq_poll();
cur = timer_read_time();
}
struct gpio_out pin = n->pin;
uint32_t expire_time = cur + 0x40000000;
while (data_len--) {
uint_fast8_t byte = *data++;
uint_fast8_t bits = 8;
while (bits--) {
// Calculate pulse duration
uint32_t on, off;
if (byte & 0x80) {
on = timer_from_ns(700 - 150);
off = timer_from_ns(600 - 150);
} else {
on = timer_from_ns(350 - 150);
off = timer_from_ns(800 - 150);
}
byte <<= 1;
// Set output high
gpio_out_toggle(pin);
uint32_t on_start_time = timer_read_time();
if (timer_is_before(expire_time, on_start_time))
goto fail;
cur = on_start_time;
while (timer_is_before(cur, on_start_time + on)) {
irq_poll();
cur = timer_read_time();
}
// Set output low
gpio_out_toggle(pin);
uint32_t off_start_time = timer_read_time();
expire_time = on_start_time + on + timer_from_ns(300);
if (timer_is_before(expire_time, off_start_time))
goto fail;
cur = off_start_time;
while (timer_is_before(cur, off_start_time + off)) {
irq_poll();
cur = timer_read_time();
}
expire_time = off_start_time + off + timer_from_ns(300);
}
}
n->last_req_time = cur;
return 0;
fail:
// A hardware irq messed up the transmission - report a failure
n->last_req_time = cur;
return -1;
}
void
command_neopixel_send(uint32_t *args)
{
uint8_t oid = args[0];
struct neopixel_s *n = oid_lookup(oid, command_config_neopixel);
uint_fast8_t data_len = args[1];
uint8_t *data = (void*)(size_t)args[2];
uint_fast8_t retry = 8;
while (retry--) {
int ret = send_data(n, data, data_len);
if (!ret)
break;
}
}
#if !CONFIG_MACH_AVR
DECL_COMMAND(command_neopixel_send, "neopixel_send oid=%c data=%*s");
#endif
|
