sounder.pio

.program sounder

.wrap_target
    pull;       blocks
    out X, 31;
    out Y, 1;
loop:
    set pins, 0     [31];
    jmp !Y, noSound [31];
    set pins, 1     [ 0];
noSound:
    nop             [30];
    jmp X--, loop   [31];
    irq 1;
.wrap


% c-sdk {
#include "hardware/clocks.h"

static inline void sounder_program_init(PIO pio, uint sm, uint offset, uint pin)
{
    pio_gpio_init(pio, pin);
    pio_sm_set_consecutive_pindirs(pio, sm, pin, 1, true);

    pio_sm_config c = sounder_program_get_default_config(offset);
    
    // OSR shift_right, auto_pull, threshould
    sm_config_set_out_shift(&c, true, false, 32);
    
    //sm_config_set_out_pins(&c, pin, 1);
    sm_config_set_set_pins(&c, pin, 1);
    
    // all the FIFOs is TX
    //sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_TX);
    sm_config_set_clkdiv(&c, (float)clock_get_hz(clk_sys) / (2000UL));

    // start state machine
    pio_sm_init(pio, sm, offset, &c);
    pio_sm_set_enabled(pio, sm, true);
}

%}