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Fix 74HC165 protocol: match RoxMux library polarity

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Key difference from RoxMux (the library designed for this hardware):
- LD pin starts HIGH, pulses LOW->HIGH to latch (was inverted)
- Data pin is INPUT (not INPUT_PULLUP) - 10k pullups on MUX board
- bitWrite instead of manual bit shifting
This commit is contained in:
Ashley Strahle
2026-06-23 13:51:21 +00:00
parent 70097057fb
commit 76dec0d359
1 changed files with 20 additions and 31 deletions
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src/pixel_stomp_mux.cpp
+20 -31
View File
@@ -1,18 +1,20 @@
#include "pixel_stomp_mux.h"
#include <Arduino.h>
#define ROXMUX_DELAY 1
PixelStompMux::PixelStompMux(uint8_t dat, uint8_t ld, uint8_t clk, uint8_t di)
: pin_dat(dat), pin_ld(ld), pin_clk(clk), pin_di(di),
strip(nullptr), last_button_state(0) {
}
void PixelStompMux::begin() {
pinMode(pin_ld, OUTPUT);
pinMode(pin_clk, OUTPUT);
pinMode(pin_di, INPUT_PULLUP);
pinMode(pin_ld, OUTPUT);
pinMode(pin_di, INPUT);
digitalWrite(pin_ld, LOW);
digitalWrite(pin_clk, LOW);
digitalWrite(pin_ld, HIGH);
strip = new Adafruit_NeoPixel(NUM_LEDS, pin_dat, NEO_GRB + NEO_KHZ800);
strip->begin();
@@ -22,19 +24,25 @@ void PixelStompMux::begin() {
Serial.printf("[MUX] Init DAT=%d LD=%d CLK=%d DI=%d\n",
pin_dat, pin_ld, pin_clk, pin_di);
Serial.printf("[MUX] 74HC165 x2 daisy-chain for %d buttons\n", NUM_BUTTONS);
Serial.printf("[MUX] WS2812C for %d LEDs\n", NUM_LEDS);
Serial.printf("[MUX] DI pin reads: %d\n", digitalRead(pin_di));
Serial.printf("[MUX] 74HC165 x2 daisy-chain, WS2812C x%d LEDs\n", NUM_LEDS);
}
uint8_t PixelStompMux::read_buttons() {
digitalWrite(pin_ld, HIGH);
delayMicroseconds(20);
digitalWrite(pin_ld, LOW);
delayMicroseconds(20);
delayMicroseconds(ROXMUX_DELAY);
digitalWrite(pin_ld, HIGH);
last_button_state = shift_in_74hc165();
return last_button_state;
uint8_t data = 0;
for (int i = 7; i >= 0; i--) {
bitWrite(data, i, digitalRead(pin_di));
digitalWrite(pin_clk, HIGH);
delayMicroseconds(ROXMUX_DELAY);
digitalWrite(pin_clk, LOW);
delayMicroseconds(ROXMUX_DELAY);
}
last_button_state = data;
return data;
}
bool PixelStompMux::is_button_pressed(uint8_t index) {
@@ -78,36 +86,17 @@ void PixelStompMux::dump() {
}
}
uint8_t PixelStompMux::shift_in_74hc165() {
uint8_t data = 0;
for (int i = NUM_BUTTONS - 1; i >= 0; i--) {
if (digitalRead(pin_di)) {
data |= (1 << i);
}
digitalWrite(pin_clk, HIGH);
delayMicroseconds(2);
digitalWrite(pin_clk, LOW);
delayMicroseconds(2);
}
return data;
}
void PixelStompMux::probe() {
Serial.println("[MUX] === Hardware Probe ===");
Serial.printf(" DI (GPIO %d) raw: %d\n", pin_di, digitalRead(pin_di));
Serial.println(" Testing LD pin...");
Serial.println(" Testing LD pin (RoxMux protocol)...");
digitalWrite(pin_ld, LOW);
delayMicroseconds(10);
Serial.printf(" LD=LOW, DI=%d\n", digitalRead(pin_di));
digitalWrite(pin_ld, HIGH);
delayMicroseconds(10);
Serial.printf(" LD=HIGH, DI=%d\n", digitalRead(pin_di));
digitalWrite(pin_ld, LOW);
delayMicroseconds(10);
Serial.println(" Toggling CLK 16 times, reading DI...");
for (int i = 0; i < 16; i++) {