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#include "HeltecRC32RotaryInput.h"
#include <Wire.h>
namespace {
constexpr uint8_t TCA6408_ADDR = 0x20;
constexpr uint8_t TCA6408_INPUT_REG = 0x00;
constexpr uint8_t TCA6408_POLARITY_REG = 0x02;
constexpr uint8_t TCA6408_CONFIG_REG = 0x03;
constexpr uint8_t TCA6408_ROTARY_A_MASK = 0x01;
constexpr uint8_t TCA6408_ROTARY_B_MASK = 0x02;
constexpr uint8_t TCA6408_ROTARY_MASK = TCA6408_ROTARY_A_MASK | TCA6408_ROTARY_B_MASK;
constexpr uint32_t TCA6408_DEBOUNCE_MS = 5;
}
bool HeltecRC32RotaryInput::begin() {
initialized = true;
ready = false;
input_state = TCA6408_ROTARY_MASK;
active_low_phase = false;
if (periph_power && !power_claimed) {
periph_power->claim();
power_claimed = true;
delay(12);
}
if (!writeRegister(TCA6408_POLARITY_REG, 0x00) || !writeRegister(TCA6408_CONFIG_REG, 0xFF)) {
return false;
}
uint8_t state = 0;
if (!readInput(state)) {
return false;
}
input_state = state & TCA6408_ROTARY_MASK;
ready = true;
return true;
}
RotaryInputEvent HeltecRC32RotaryInput::poll() {
if (!initialized) {
begin();
return RotaryInputEvent::None;
}
if (!ready) {
return RotaryInputEvent::None;
}
uint8_t new_state = 0;
if (!readInput(new_state)) {
return RotaryInputEvent::None;
}
new_state &= TCA6408_ROTARY_MASK;
RotaryInputEvent event = handleTransition(new_state);
input_state = new_state;
return event;
}
bool HeltecRC32RotaryInput::writeRegister(uint8_t reg, uint8_t value) {
Wire.beginTransmission(TCA6408_ADDR);
Wire.write(reg);
Wire.write(value);
return Wire.endTransmission() == 0;
}
bool HeltecRC32RotaryInput::readInput(uint8_t& value) {
Wire.beginTransmission(TCA6408_ADDR);
Wire.write(TCA6408_INPUT_REG);
if (Wire.endTransmission(false) != 0) {
return false;
}
if (Wire.requestFrom(TCA6408_ADDR, static_cast<uint8_t>(1)) != 1) {
return false;
}
value = Wire.read();
return true;
}
RotaryInputEvent HeltecRC32RotaryInput::handleTransition(uint8_t newState) {
uint8_t changed = (input_state ^ newState) & TCA6408_ROTARY_MASK;
RotaryInputEvent event = RotaryInputEvent::None;
bool a_low = (newState & TCA6408_ROTARY_A_MASK) == 0;
bool b_low = (newState & TCA6408_ROTARY_B_MASK) == 0;
if (!a_low && !b_low) {
active_low_phase = false;
}
if (!active_low_phase && (changed & TCA6408_ROTARY_A_MASK) && a_low && !b_low) {
event = RotaryInputEvent::Prev;
active_low_phase = true;
} else if (!active_low_phase && (changed & TCA6408_ROTARY_B_MASK) && b_low && !a_low) {
event = RotaryInputEvent::Next;
active_low_phase = true;
}
if (event == RotaryInputEvent::None && !active_low_phase && (changed & TCA6408_ROTARY_A_MASK)) {
bool a_rising = (newState & TCA6408_ROTARY_A_MASK) != 0;
if (a_rising && b_low) {
event = RotaryInputEvent::Prev;
}
}
if (event == RotaryInputEvent::None && !active_low_phase && (changed & TCA6408_ROTARY_B_MASK)) {
bool b_rising = (newState & TCA6408_ROTARY_B_MASK) != 0;
if (b_rising && a_low) {
event = RotaryInputEvent::Next;
}
}
if (event == RotaryInputEvent::None || (millis() - last_event_ms) < TCA6408_DEBOUNCE_MS) {
return RotaryInputEvent::None;
}
last_event_ms = millis();
return event;
}