- /*
- * 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);
-
- void ws2812_setleds(LED_TYPE *ledarray, uint16_t number_of_leds) {
- DDRx_ADDRESS(RGB_DI_PIN) |= pinmask(RGB_DI_PIN);
-
- uint8_t masklo = ~(pinmask(RGB_DI_PIN)) & PORTx_ADDRESS(RGB_DI_PIN);
- uint8_t maskhi = pinmask(RGB_DI_PIN) | PORTx_ADDRESS(RGB_DI_PIN);
-
- ws2812_sendarray_mask((uint8_t *)ledarray, number_of_leds * sizeof(LED_TYPE), masklo, maskhi);
-
- _delay_us(WS2812_TRST_US);
- }
-
- /*
- This routine writes an array of bytes with RGB values to the Dataout pin
- using the fast 800kHz clockless WS2811/2812 protocol.
- */
-
- // 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) * WS2812_T0H) / 1000000)
- #define w_onecycles (((F_CPU / 1000) * WS2812_T1H + 500000) / 1000000)
- #define w_totalcycles (((F_CPU / 1000) * WS2812_TIMING + 500000) / 1000000)
-
- // w1_nops - nops between rising edge and falling edge - low
- #if w_zerocycles >= w_fixedlow
- # define w1_nops (w_zerocycles - w_fixedlow)
- #else
- # define w1_nops 0
- #endif
-
- // w2_nops - nops between fe low and fe high
- #if w_onecycles >= (w_fixedhigh + w1_nops)
- # define w2_nops (w_onecycles - w_fixedhigh - w1_nops)
- #else
- # define w2_nops 0
- #endif
-
- // w3_nops - nops to complete loop
- #if w_totalcycles >= (w_fixedtotal + w1_nops + w2_nops)
- # define w3_nops (w_totalcycles - w_fixedtotal - w1_nops - w2_nops)
- #else
- # define w3_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
-
- #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;
- }
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