diff options
Diffstat (limited to 'platforms/avr/drivers/ws2812.c')
| -rw-r--r-- | platforms/avr/drivers/ws2812.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/platforms/avr/drivers/ws2812.c b/platforms/avr/drivers/ws2812.c new file mode 100644 index 0000000000..77c492cd4c --- /dev/null +++ b/platforms/avr/drivers/ws2812.c @@ -0,0 +1,176 @@ +/* + * 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; +} |