stepper.pio

.program stepper_1
;.side_set 1

.define public STD 1

.wrap_target
bitloop:
    out x, 1       ; Side-set still takes place when instruction stalls
    jmp !x do_zero ; Branch on the bit we shifted out
do_one:
    set pins 1     [STD + 3]
    set pins 0     [STD]
    jmp  bitloop   
do_zero:
    set pins 0   ; Or drive low, for a short pulse
.wrap

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

static inline void stepper_1_program_init(PIO pio, uint sm, uint offset, uint pin, float freq, bool step) {

    pio_gpio_init(pio, pin);
    pio_sm_set_consecutive_pindirs(pio, sm, pin, 1, true);

    pio_sm_config c = stepper_1_program_get_default_config(offset);
    sm_config_set_set_pins(&c, pin, 1);
    sm_config_set_out_shift(&c, false, true, step ? 32 : 32);
    sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_TX);

    float div = clock_get_hz(clk_sys) / (freq);
    sm_config_set_clkdiv(&c, div);

    pio_sm_init(pio, sm, offset, &c);
    pio_sm_set_enabled(pio, sm, true);
}
%}