Add expression pedal support on GPIO5 (CC 4)

2026-07-02 04:00:06 +00:00
parent ae2891fca8
commit 08d6fc8701
3 changed files with 88 additions and 1 deletions
@@ -0,0 +1,50 @@
+#include "expression_pedal.h"
+#include "midi_transport.h"
+#include <Arduino.h>
+
+ExpressionPedal::ExpressionPedal(uint8_t adc_pin)
+    : adc_pin(adc_pin)
+    , current_value(0)
+    , last_sent_value(255)
+    , midi_channel(1)
+    , midi_cc(4)
+    , last_read_time(0)
+{
+}
+
+void ExpressionPedal::begin() {
+    Serial.printf("[EXP] Expression pedal on ADC1_CH4 (GPIO%d)\n", adc_pin);
+    analogReadResolution(12);
+    pinMode(adc_pin, INPUT);
+    delay(10);
+    uint16_t initial = analogRead(adc_pin);
+    current_value = adc_to_midi(initial);
+    last_sent_value = current_value;
+    Serial.printf("[EXP] Initial ADC: %d -> MIDI: %d\n", initial, current_value);
+}
+
+void ExpressionPedal::update(UsbMidiTransport& midi) {
+    uint32_t now = millis();
+    if (now - last_read_time < READ_INTERVAL_MS) return;
+    last_read_time = now;
+
+    uint16_t raw = analogRead(adc_pin);
+    uint8_t new_value = adc_to_midi(raw);
+
+    if (new_value > current_value + HYSTERESIS ||
+        new_value + HYSTERESIS < current_value ||
+        (new_value != current_value && (new_value == 0 || new_value == 127))) {
+        current_value = new_value;
+    }
+
+    if (current_value != last_sent_value) {
+        last_sent_value = current_value;
+        midi.send_cc(midi_channel, midi_cc, current_value);
+        Serial.printf("[EXP] CC%d: %d\n", midi_cc, current_value);
+    }
+}
+
+uint8_t ExpressionPedal::adc_to_midi(uint16_t adc_value) {
+    uint32_t scaled = (uint32_t)adc_value * 127 / 4095;
+    return (uint8_t)scaled;
+}