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/*
* 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.
*/
// 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 - 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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