qmk_firmware/drivers/avr/ws2812.c

/*
 * 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>

/*
 * 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.
 */

void ws2812_sendarray(uint8_t *array, uint16_t length);
void ws2812_sendarray_mask(uint8_t *array, uint16_t length, uint8_t pinmask);

#ifdef RGBW_BB_TWI

// Port for the I2C
#    define I2C_DDR DDRD
#    define I2C_PIN PIND
#    define I2C_PORT PORTD

// Pins to be used in the bit banging
#    define I2C_CLK 0
#    define I2C_DAT 1

#    define I2C_DATA_HI()           \
        I2C_DDR &= ~(1 << I2C_DAT); \
        I2C_PORT |= (1 << I2C_DAT);
#    define I2C_DATA_LO()          \
        I2C_DDR |= (1 << I2C_DAT); \
        I2C_PORT &= ~(1 << I2C_DAT);

#    define I2C_CLOCK_HI()          \
        I2C_DDR &= ~(1 << I2C_CLK); \
        I2C_PORT |= (1 << I2C_CLK);
#    define I2C_CLOCK_LO()         \
        I2C_DDR |= (1 << I2C_CLK); \
        I2C_PORT &= ~(1 << I2C_CLK);

#    define I2C_DELAY 1

void I2C_WriteBit(unsigned char c) {
    if (c > 0) {
        I2C_DATA_HI();
    } else {
        I2C_DATA_LO();
    }

    I2C_CLOCK_HI();
    _delay_us(I2C_DELAY);

    I2C_CLOCK_LO();
    _delay_us(I2C_DELAY);

    if (c > 0) {
        I2C_DATA_LO();
    }

    _delay_us(I2C_DELAY);
}

// Inits bitbanging port, must be called before using the functions below
//
void I2C_Init(void) {
    I2C_PORT &= ~((1 << I2C_DAT) | (1 << I2C_CLK));

    I2C_CLOCK_HI();
    I2C_DATA_HI();

    _delay_us(I2C_DELAY);
}

// Send a START Condition
//
void I2C_Start(void) {
    // set both to high at the same time
    I2C_DDR &= ~((1 << I2C_DAT) | (1 << I2C_CLK));
    _delay_us(I2C_DELAY);

    I2C_DATA_LO();
    _delay_us(I2C_DELAY);

    I2C_CLOCK_LO();
    _delay_us(I2C_DELAY);
}

// Send a STOP Condition
//
void I2C_Stop(void) {
    I2C_CLOCK_HI();
    _delay_us(I2C_DELAY);

    I2C_DATA_HI();
    _delay_us(I2C_DELAY);
}

// write a byte to the I2C slave device
//
unsigned char I2C_Write(unsigned char c) {
    for (char i = 0; i < 8; i++) {
        I2C_WriteBit(c & 128);

        c <<= 1;
    }

    I2C_WriteBit(0);
    _delay_us(I2C_DELAY);
    _delay_us(I2C_DELAY);

    // _delay_us(I2C_DELAY);
    // return I2C_ReadBit();
    return 0;
}

#endif

// Setleds for standard RGB
void inline ws2812_setleds(LED_TYPE *ledarray, uint16_t leds) {
    // ws2812_setleds_pin(ledarray,leds, _BV(ws2812_pin));
    ws2812_setleds_pin(ledarray, leds, _BV(RGB_DI_PIN & 0xF));
}

void inline ws2812_setleds_pin(LED_TYPE *ledarray, uint16_t leds, uint8_t pinmask) {
#ifdef RGBW_BB_TWI
    uint8_t sreg_prev, twcr_prev;
    sreg_prev = SREG;
    twcr_prev = TWCR;
    cli();
    TWCR &= ~(1 << TWEN);
    I2C_Init();
    I2C_Start();
    I2C_Write(0x84);
    uint16_t datlen = leds << 2;
    uint8_t  curbyte;
    uint8_t *data = (uint8_t *)ledarray;
    while (datlen--) {
        curbyte = *data++;
        I2C_Write(curbyte);
    }
    I2C_Stop();
    SREG = sreg_prev;
    TWCR = twcr_prev;
#endif
    // ws2812_DDRREG |= pinmask; // Enable DDR
    // new universal format (DDR)
    _SFR_IO8((RGB_DI_PIN >> 4) + 1) |= pinmask;

    ws2812_sendarray_mask((uint8_t *)ledarray, leds * sizeof(LED_TYPE), pinmask);

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

void ws2812_sendarray(uint8_t *data, uint16_t datlen) { ws2812_sendarray_mask(data, datlen, _BV(RGB_DI_PIN & 0xF)); }

/*
  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

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

    // masklo  =~maskhi&ws2812_PORTREG;
    // maskhi |=        ws2812_PORTREG;
    masklo = ~maskhi & _SFR_IO8((RGB_DI_PIN >> 4) + 2);
    maskhi |= _SFR_IO8((RGB_DI_PIN >> 4) + 2);
    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(_SFR_IO8((RGB_DI_PIN >> 4) + 2))), "r"(maskhi), "r"(masklo));
    }

    SREG = sreg_prev;
}