44 lines
1.3 KiB
Plaintext
44 lines
1.3 KiB
Plaintext
; --------------------------------------------------
|
|
; Quadrature Output using PIO
|
|
; by Christopher (@ZodiusInfuser) Parrott
|
|
; --------------------------------------------------
|
|
;
|
|
; A simple PIO that will create a quadrature output signal
|
|
; for use with testing quadrature decoder code
|
|
|
|
|
|
; Constants
|
|
; --------------------------------------------------
|
|
.define public QUAD_OUT_SET_CYCLES 10
|
|
|
|
|
|
.program quadrature_out
|
|
.wrap_target
|
|
set pins, 0 [QUAD_OUT_SET_CYCLES - 1]
|
|
set pins, 1 [QUAD_OUT_SET_CYCLES - 1]
|
|
set pins, 3 [QUAD_OUT_SET_CYCLES - 1]
|
|
set pins, 2 [QUAD_OUT_SET_CYCLES - 1]
|
|
.wrap
|
|
|
|
|
|
; Initialisation Code
|
|
; --------------------------------------------------
|
|
% c-sdk {
|
|
#include "hardware/clocks.h"
|
|
|
|
void quadrature_out_program_init(PIO pio, uint sm, uint offset, uint pin, float freq)
|
|
{
|
|
pio_gpio_init(pio, pin);
|
|
pio_gpio_init(pio, pin + 1);
|
|
pio_sm_set_consecutive_pindirs(pio, sm, pin, 2, true);
|
|
pio_sm_config c = quadrature_out_program_get_default_config(offset);
|
|
sm_config_set_set_pins(&c, pin, 2);
|
|
|
|
int cycles_per_bit = QUAD_OUT_SET_CYCLES * 4;
|
|
float div = clock_get_hz(clk_sys) / (freq * cycles_per_bit);
|
|
sm_config_set_clkdiv(&c, div);
|
|
|
|
pio_sm_init(pio, sm, offset, &c);
|
|
pio_sm_set_enabled(pio, sm, true);
|
|
}
|
|
%} |