-
Notifications
You must be signed in to change notification settings - Fork 3
/
light_ws2812.cpp
162 lines (143 loc) · 3.73 KB
/
light_ws2812.cpp
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
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
/*
* light weight WS2812 lib V2.1 - Arduino support
*
* Controls WS2811/WS2812/WS2812B RGB-LEDs
* Author: Tim (cpldcpu@gmail.com)
*
* Jan 18th, 2014 v2.0b Initial Version
* March 7th, 2014 v2.1 Added option to retarget the port register during runtime
* Removes inlining to allow compiling with c++
*
* April 2nd, 2015 added global brightness -- Marv
*
* License: GNU GPL v2 (see License.txt)
*/
#include "WS2812.h"
/*
This routine writes an array of bytes with RGB values to the Dataout pin
using the fast 800kHz clockless WS2811/2812 protocol.
*/
// Timing in ns
#define w_zeropulse 350
#define w_onepulse 900
#define w_totalperiod 1250
// Fixed cycles used by the inner loop
#define w_fixedlow 3
#define w_fixedhigh 6
#define w_fixedtotal 10
// Insert NOPs to match the timing, if possible
#define w_zerocycles (((F_CPU/1000)*w_zeropulse )/1000000)
#define w_onecycles (((F_CPU/1000)*w_onepulse +500000)/1000000)
#define w_totalcycles (((F_CPU/1000)*w_totalperiod +500000)/1000000)
// w1 - nops between rising edge and falling edge - low
#define w1 (w_zerocycles-w_fixedlow)
// w2 nops between fe low and fe high
#define w2 (w_onecycles-w_fixedhigh-w1)
// w3 nops to complete loop
#define w3 (w_totalcycles-w_fixedtotal-w1-w2)
#if w1>0
#define w1_nops w1
#else
#define w1_nops 0
#endif
// The only critical timing parameter is the minimum pulse length of the "0"
// Warn or throw error if this timing can not be met with current F_CPU settings.
#define w_lowtime ((w1_nops+w_fixedlow)*1000000)/(F_CPU/1000)
#if w_lowtime>550
#error "Light_ws2812: Sorry, the clock speed is too low. Did you set F_CPU correctly?"
#elif w_lowtime>450
#warning "Light_ws2812: The timing is critical and may only work on WS2812B, not on WS2812(S)."
#warning "Please consider a higher clockspeed, if possible"
#endif
#if w2>0
#define w2_nops w2
#else
#define w2_nops 0
#endif
#if w3>0
#define w3_nops w3
#else
#define w3_nops 0
#endif
#define w_nop1 "nop \n\t"
#define w_nop2 "rjmp .+0 \n\t"
#define w_nop4 w_nop2 w_nop2
#define w_nop8 w_nop4 w_nop4
#define w_nop16 w_nop8 w_nop8
void WS2812::ws2812_sendarray_mask(uint8_t *data,uint16_t datlen,uint8_t maskhi,uint8_t *port, uint8_t *portreg)
{
uint8_t curbyte,ctr,masklo;
uint8_t sreg_prev;
masklo = ~maskhi & *port;
maskhi |= *port;
sreg_prev=SREG;
cli();
while (datlen--) {
curbyte=*data++;
#ifdef USE_GLOBAL_BRIGHTNESS
curbyte=(int)((curbyte)*(int)(brightness) ) >>8;
#endif
asm volatile(
" ldi %0,8 \n\t"
"loop%=: \n\t"
" st X,%3 \n\t" // '1' [02] '0' [02] - re
#if (w1_nops&1)
w_nop1
#endif
#if (w1_nops&2)
w_nop2
#endif
#if (w1_nops&4)
w_nop4
#endif
#if (w1_nops&8)
w_nop8
#endif
#if (w1_nops&16)
w_nop16
#endif
" sbrs %1,7 \n\t" // '1' [04] '0' [03]
" st X,%4 \n\t" // '1' [--] '0' [05] - fe-low
" lsl %1 \n\t" // '1' [05] '0' [06]
#if (w2_nops&1)
w_nop1
#endif
#if (w2_nops&2)
w_nop2
#endif
#if (w2_nops&4)
w_nop4
#endif
#if (w2_nops&8)
w_nop8
#endif
#if (w2_nops&16)
w_nop16
#endif
" brcc skipone%= \n\t" // '1' [+1] '0' [+2] -
" st X,%4 \n\t" // '1' [+3] '0' [--] - fe-high
"skipone%=: " // '1' [+3] '0' [+2] -
#if (w3_nops&1)
w_nop1
#endif
#if (w3_nops&2)
w_nop2
#endif
#if (w3_nops&4)
w_nop4
#endif
#if (w3_nops&8)
w_nop8
#endif
#if (w3_nops&16)
w_nop16
#endif
" dec %0 \n\t" // '1' [+4] '0' [+3]
" brne loop%=\n\t" // '1' [+5] '0' [+4]
: "=&d" (ctr)
// : "r" (curbyte), "I" (_SFR_IO_ADDR(ws2812_PORTREG)), "r" (maskhi), "r" (masklo)
: "r" (curbyte), "x" (port), "r" (maskhi), "r" (masklo)
);
}
SREG=sreg_prev;
}