ws2818b.pio

.program ws2818b
.side_set 1
.wrap_target
    out x, 1        side 0 [2]
    jmp !x, 3       side 1 [1]
    jmp 0           side 1 [4]
    nop             side 0 [4]
.wrap 


% c-sdk {
void ws2818b_program_init(PIO pio, uint sm, uint offset, uint pin, float freq);

#ifndef __WS2818B_PROGRAM_INIT_INC
#define __WS2818B_PROGRAM_INIT_INC

#include "hardware/clocks.h"

void ws2818b_program_init(PIO pio, uint sm, uint offset, uint pin, float freq) {

  pio_gpio_init(pio, pin);
  
  pio_sm_set_consecutive_pindirs(pio, sm, pin, 1, true);
  
  // Program configuration.
  pio_sm_config c = ws2818b_program_get_default_config(offset);
  sm_config_set_sideset_pins(&c, pin); // Uses sideset pins.
  sm_config_set_out_shift(&c, true, true, 8); // 8 bit transfers, right-shift.
  sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_TX); // Use only TX FIFO.
  float prescaler = clock_get_hz(clk_sys) / (10.f * freq); // 10 cycles per transmission, freq is frequency of encoded bits.
  sm_config_set_clkdiv(&c, prescaler);
  
  pio_sm_init(pio, sm, offset, &c);
  pio_sm_set_enabled(pio, sm, true);
}
#endif
%}