summaryrefslogtreecommitdiffstats
path: root/drivers/avr/ws2812.c
blob: 5c3d72dcb5e8d01efc42d316bd511a989bb9611a (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
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
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
/*
 * light weight WS2812 lib V2.0b
 *
 * Controls WS2811/WS2812/WS2812B RGB-LEDs
 * Author: Tim (cpldcpu@gmail.com)
 *
 * Jan 18th, 2014  v2.0b Initial Version
 * Nov 29th, 2015  v2.3  Added SK6812RGBW support
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "ws2812.h"
#include <avr/interrupt.h>
#include <avr/io.h>
#include <util/delay.h>

#define pinmask(pin) (_BV((pin)&0xF))

/*
 * Forward declare internal functions
 *
 * The functions take a byte-array and send to the data output as WS2812 bitstream.
 * The length is the number of bytes to send - three per LED.
 */

static inline void ws2812_sendarray_mask(uint8_t *data, uint16_t datlen, uint8_t masklo, uint8_t maskhi);

// Setleds for standard RGB
void inline ws2812_setleds(LED_TYPE *ledarray, uint16_t number_of_leds) {
    // wrap up usage of RGB_DI_PIN
    ws2812_setleds_pin(ledarray, number_of_leds, RGB_DI_PIN);
}

void ws2812_setleds_pin(LED_TYPE *ledarray, uint16_t number_of_leds, uint8_t pin) {
    DDRx_ADDRESS(RGB_DI_PIN) |= pinmask(pin);

    uint8_t masklo = ~(pinmask(pin)) & PORTx_ADDRESS(pin);
    uint8_t maskhi = pinmask(pin) | PORTx_ADDRESS(pin);

    ws2812_sendarray_mask((uint8_t *)ledarray, number_of_leds * sizeof(LED_TYPE), masklo, maskhi);

#ifdef RGBW
    _delay_us(80);
#else
    _delay_us(50);
#endif
}

/*
  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 2
#define w_fixedhigh 4
#define w_fixedtotal 8

// 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

static inline void ws2812_sendarray_mask(uint8_t *data, uint16_t datlen, uint8_t masklo, uint8_t maskhi) {
    uint8_t curbyte, ctr, sreg_prev;

    sreg_prev = SREG;
    cli();

    while (datlen--) {
        curbyte = (*data++);

        asm volatile("       ldi   %0,8  \n\t"
                     "loop%=:            \n\t"
                     "       out   %2,%3 \n\t"  //  '1' [01] '0' [01] - 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' [03] '0' [02]
                     "       out   %2,%4 \n\t"  //  '1' [--] '0' [03] - fe-low
                     "       lsl   %1    \n\t"  //  '1' [04] '0' [04]
#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
                     "       out   %2,%4 \n\t"  //  '1' [+1] '0' [+1] - fe-high
#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' [+2] '0' [+2]
                     "       brne  loop%=\n\t"  //  '1' [+3] '0' [+4]
                     : "=&d"(ctr)
                     : "r"(curbyte), "I"(_SFR_IO_ADDR(PORTx_ADDRESS(RGB_DI_PIN))), "r"(maskhi), "r"(masklo));
    }

    SREG = sreg_prev;
}