trigger_basic.pio

.program trigger_basic
.side_set 2

; These bits have to be consecutive in the GPIO index too
; bit 0 : gpio_pulse_go
; bit 1 : gpio_trigger_out_debug

.wrap_target
                                    ; todo: enable autopull
                                    ; actually mov from osr with autopull is undefined, 
                                    ; so dont enable autopull
    pull block          side 0b00
    mov x osr           side 0b00   ; read delay into scratch x
    pull block          side 0b00
    mov y osr           side 0b00   ; read length into scratch y
    irq clear 0         side 0b00   ; clear IRQ before starting
    wait 1 PIN 0        side 0b10   ; wait for trigger input to go high (polarity=1), 
                                    ; on the first input gpio (defined below),
                                    ; and sideset gpio_trigger_out_debug high
    ; nop                 side 0b10   ;      -> nop instead of wait, gpio_trigger_out_debug high
delay_loop:
    jmp x-- delay_loop  side 0b10   ; count down the delay
pulse_loop:
    jmp y-- pulse_loop  side 0b01   ; count down the pulse length
    irq set 0           side 0b00   ; pulse stop, signal that program is finished with IRQ
.wrap

% c-sdk {
static inline void trigger_basic_init(PIO pio, uint sm, uint offset, 
    uint trigger_in, uint trigger_pulse_go) {

    // TODO: trigger_in

    pio_sm_config c = trigger_basic_program_get_default_config(offset);

    // trigger_out_debug follows trigger_pulse_go sequentually
    // void pio_sm_set_consecutive_pindirs (PIO pio,
    //     uint sm,
    //     uint pin_base,
    //     uint pin_count,
    //     bool is_out)
    pio_sm_set_consecutive_pindirs(pio, sm, trigger_pulse_go, 2, true);

    pio_sm_set_consecutive_pindirs(pio, sm, trigger_in, 1, false);

    // init the GPIOs
    pio_gpio_init(pio, trigger_in);
    pio_gpio_init(pio, trigger_pulse_go);
    pio_gpio_init(pio, trigger_pulse_go+1);

    // configure the sideset pin count
    // static void sm_config_set_sideset (pio_sm_config *c,
    //     uint bit_count,
    //     bool optional,
    //     bool pindirs)
    sm_config_set_sideset(&c, 2, false, false);
    
    // configure the sideset pins
    // static void sm_config_set_sideset_pins (pio_sm_config *c,
    //     uint sideset_base)
    // trigger_out_debug follows trigger_pulse_go sequentually
    sm_config_set_sideset_pins(&c, trigger_pulse_go);

    // configure input pins
    // static void sm_config_set_in_pins (pio_sm_config *c,
    //    uint in_base)
    sm_config_set_in_pins(&c, trigger_in);

    // Load our configuration, and jump to the start of the program
    pio_sm_init(pio, sm, offset, &c);
    // Set the state machine running
    pio_sm_set_enabled(pio, sm, true);
}
%}