lightning_tx.pio

.program lightning_tx

; 1 NOP is 0.5us

SET PINS 1
SET PINDIRS 1
send:
    ; Pull in one byte from OSR
    PULL
    ; Output counter (reg X)
    SET X, 7

continue_send:
    ; Pull 1 bit from OSR
    OUT Y 1

    ; if Y is zero we send a (you guessed it) zero
    JMP !Y send_zero

    ; otherwise we send a 1
send_one:
    SET PINS 0 [3]
    SET PINS 1 [11]
    JMP send_done
send_zero:
    SET PINS 0 [13]
    SET PINS 1 [2]
send_done:
    JMP X-- continue_send
    NOP [14]
    PUSH [15]


% c-sdk {
static inline pio_sm_config lightning_tx_program_init(PIO pio, uint sm, uint offset, uint pin, float clkdiv) {


    pio_sm_set_pins_with_mask(pio, sm, 1u << pin, 1u << pin);
    pio_sm_set_pindirs_with_mask(pio, sm, 1u << pin, 1u << pin);
    //pio_sm_set_pindirs_with_mask(pio, sm, 1u << 19, 0u << pin);
    pio_gpio_init(pio, 19);


    pio_sm_config c = lightning_tx_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_pins(&c, pin, 1);
    sm_config_set_set_pins(&c, pin, 1);
    sm_config_set_in_pins(&c, pin);
sm_config_set_jmp_pin(&c, pin);
    //pio_sm_set_sideset_pins(pio, sm, 19);
    //sm_config_set_sideset_pins(&c, 19);

    // shift_right = false, auto_push = false
    sm_config_set_in_shift(&c, false, false, 32);
    // shift_right = true, auto_pull = false
    sm_config_set_out_shift(&c, true, false, 32);
    
    // Set this pin's GPIO function (connect PIO to the pad)
    pio_gpio_init(pio, pin);
    pio_gpio_init(pio, 19);
    // Set the pin direction to output at the PIO
    //pio_sm_set_consecutive_pindirs(pio, sm, pin, 1, false);
    sm_config_set_clkdiv(&c, clkdiv);
    

    // 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);
    return c;
}
%}