pico-hf-oscillator/piodco/dco.pio

.program dco
    set x, 0
    set y, 0

.wrap_target        //                                              CYCLES
    pull            // load full 32-bit register.                   1c
    out y, 8        // load 8-bit delay value.                      2c
    mov x, y        // copy value in order to do next PI cycle.     3c
LOOP0:
    jmp x-- LOOP0   // do exactly X*CPU CLK delay.                  4c+x
    set pins, 1 [3] // set output high.                             5c+x
    
LOOP1:
    jmp y-- LOOP1   // do exactly X*CPU CLK delay.                  8c+x
    set pins, 0     // set output high.                             9c+x

    // RPix: The next sections repeat aforementioned algo 3 times.
    out y, 8
    mov x, y [1]
LOOP2:
    jmp x-- LOOP2
    set pins, 1 [3]
LOOP3:
    jmp y-- LOOP3
    set pins, 0


    out y, 8
    mov x, y [1]
LOOP4:
    jmp x-- LOOP4
    set pins, 1 [3]
LOOP5:
    jmp y-- LOOP5
    set pins, 0


    out y, 8
    mov x, y [1]
LOOP6:
    jmp x-- LOOP6
    set pins, 1 [3]
LOOP7:
    jmp y-- LOOP7
    set pins, 0

.wrap

% c-sdk {

#define PIOASM_DELAY_CYCLES 5

static inline void dco_program_init(PIO pio, uint sm, uint offset, uint pin)
{
    pio_sm_config c = dco_program_get_default_config(offset);
    sm_config_set_out_pins(&c, pin, 1);
    pio_gpio_init(pio, pin);

    sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_TX);
    //sm_config_set_out_shift(&c, true, true, 32);           // Autopull.

    pio_sm_set_consecutive_pindirs(pio, sm, pin, 1, true);
    
    sm_config_set_clkdiv_int_frac(&c, 1u, 0u);

    pio_sm_init(pio, sm, offset, &c);
    pio_sm_set_enabled(pio, sm, true);
}
//
static inline void dco_program_puts(PIO pio, uint sm, const uint32_t *s)
{
    pio_sm_put_blocking(pio, sm, s[0]);
    pio_sm_put_blocking(pio, sm, s[1]);
    pio_sm_put_blocking(pio, sm, s[2]);
    pio_sm_put_blocking(pio, sm, s[3]);
    pio_sm_put_blocking(pio, sm, s[4]);
    pio_sm_put_blocking(pio, sm, s[5]);
    pio_sm_put_blocking(pio, sm, s[6]);
    pio_sm_put_blocking(pio, sm, s[7]);
}

static inline void dco_program_puts1w(PIO pio, uint sm, const uint32_t val)
{
    pio_sm_put_blocking(pio, sm, val);
}
%}