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Change duty cycle of PIO Tone to 50% (#2770)

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Markus Gyger 2025-01-22 01:03:31 +07:00 committed by GitHub
parent 5a34395f46
commit b3d0ccc7e3
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GPG key ID: B5690EEEBB952194
3 changed files with 14 additions and 17 deletions
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7
cores/rp2040/Tone.cpp
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@ -71,10 +71,7 @@ void tone(uint8_t pin, unsigned int frequency, unsigned long duration) {
return; // Weird deadlock case
}
int us = 1'000'000 / frequency / 2;
if (us < 5) {
us = 5;
}
unsigned int delay = (RP2040::f_cpu() + frequency) / (frequency * 2) - 3; // rounded
auto entry = _toneMap.find(pin);
Tone *newTone;
if (entry == _toneMap.end()) {
@ -99,7 +96,7 @@ void tone(uint8_t pin, unsigned int frequency, unsigned long duration) {
tone2_program_init(newTone->pio, newTone->sm, newTone->off, pin);
}
pio_sm_clear_fifos(newTone->pio, newTone->sm); // Remove any old updates that haven't yet taken effect
pio_sm_put_blocking(newTone->pio, newTone->sm, RP2040::usToPIOCycles(us));
pio_sm_put_blocking(newTone->pio, newTone->sm, delay);
pio_sm_exec(newTone->pio, newTone->sm, pio_encode_pull(false, false));
pio_sm_exec(newTone->pio, newTone->sm, pio_encode_mov(pio_x, pio_osr));
pio_sm_set_enabled(newTone->pio, newTone->sm, true);

9
cores/rp2040/tone2.pio
View file

@ -18,7 +18,7 @@
; Side-set pin 0 is used for Tone output
; OSR == Halfcycle count
; OSR == Halfcycle count - 3
.program tone2
.side_set 1 opt
@ -26,10 +26,11 @@
; pull ; TXFIFO -> OSR, or X -> OSR if no new period
; mov x, osr ; OSR -> X
.wrap_target
high:
pull noblock ; Potentially grab new HALFCYCLECOUNT, OTW copy from backup in X
mov x, osr ; OSR -> X
mov y, osr side 1 ; HALFCYCLECOUNT -> Y
mov x, osr side 1 ; OSR -> X
mov y, osr ; HALFCYCLECOUNT -> Y
highloop:
jmp y-- highloop ; while (y--) { /* noop delay */ }
@ -38,7 +39,7 @@ low:
lowloop:
jmp y-- lowloop ; while (y--) { /* noop delay */ }
jmp high ; GOTO high
.wrap ; GOTO high
% c-sdk {
static inline void tone2_program_init(PIO pio, uint sm, uint offset, uint pin) {

11
cores/rp2040/tone2.pio.h
View file

@ -13,27 +13,26 @@
// ----- //
#define tone2_wrap_target 0
#define tone2_wrap 6
#define tone2_wrap 5
#define tone2_pio_version 0
static const uint16_t tone2_program_instructions[] = {
// .wrap_target
0x8080, // 0: pull noblock
0xa027, // 1: mov x, osr
0xb847, // 2: mov y, osr side 1
0xb827, // 1: mov x, osr side 1
0xa047, // 2: mov y, osr
0x0083, // 3: jmp y--, 3
0xb047, // 4: mov y, osr side 0
0x0085, // 5: jmp y--, 5
0x0000, // 6: jmp 0
// .wrap
};
#if !PICO_NO_HARDWARE
static const struct pio_program tone2_program = {
.instructions = tone2_program_instructions,
.length = 7,
.length = 6,
.origin = -1,
.pio_version = 0,
.pio_version = tone2_pio_version,
#if PICO_PIO_VERSION > 0
.used_gpio_ranges = 0x0
#endif