;
; Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
;
; SPDX-License-Identifier: BSD-3-Clause
;

.program pio_dac

; Repeatedly get one word of data from the TX FIFO, stalling when the FIFO is
; empty. Write the least significant bit to the OUT pin group.

.wrap_target
    out pins, 1
.wrap

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

static inline void pio_dac_program_init(PIO pio, uint sm, uint offset, uint pin, float fs) {
    pio_sm_config c = pio_dac_program_get_default_config(offset);

    // Map the state machine's OUT pin group to one pin, namely the `pin`
    // parameter to this function.
    sm_config_set_out_shift(&c, true, true, 32);
    sm_config_set_out_pins(&c, pin, 1);
    sm_config_set_clkdiv(&c, (float)clock_get_hz(clk_sys) / fs);

    // Set this pin's GPIO function (connect PIO to the pad)
    pio_gpio_init(pio, pin);

    // Set the pin direction to output at the PIO
    pio_sm_set_consecutive_pindirs(pio, sm, pin, 1, true);

    // 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);
}
%}