/** * @file main.c * @brief Bike rear light implementation for ATTINY202. * */ #include #include #include #include /** @defgroup LED_Masks LED bitmasks for PORTA * @{ */ #define BUTTON_PIN_MASK 0x01 // PA0 #define PA1_SET_MASK 0x02 ///< LED 1–2 #define PA2_SET_MASK 0x04 ///< LED 3–6 #define PA3_SET_MASK 0x08 ///< LED 7–8 #define PA6_SET_MASK 0x40 ///< Green LED pin #define PA7_SET_MASK 0x80 ///< Red LED /** @} */ #define MAIN_LOOP_SLEEP 10U // Main loop delay in ms (system tick) #define BUTTON_LONG_PRESS_DURATION_MS 1000U // Long press detection threshold #define BUTTON_IGNORE_DURATION_MS 1000U // Time that the button is ignored after a long press /** @brief Convert milliseconds to system ticks (integer division). */ #define MS_TO_TICKS(ms) ((ms) / MAIN_LOOP_SLEEP) /** @brief Global flags */ volatile bool bLedEnabled = true; volatile bool bBtnPressed = false; // Function forward declarations void blinkLed(bool resetCounters); static inline void leds_off(void); static inline void leds_on(void); static void handleSwitch(void); /** * @brief Main entry point. * * Initializes I/O ports and runs the main loop, periodically calling @ref blinkLed(). * * @return never returns */ int main(void) { // --- configure LED pins as outputs --- VPORTA.DIR = (PA1_SET_MASK | PA2_SET_MASK | PA3_SET_MASK | /*PA6_SET_MASK |*/ // PA6 now input (switch) PA7_SET_MASK); // Configure PA0 as input with pull-up VPORTA.DIR &= ~BUTTON_PIN_MASK; // Input PORTA.PIN0CTRL = PORT_PULLUPEN_bm; // Pull-up enabled // --- ensure all LEDs off at startup --- leds_off(); VPORTA.OUT &= (uint8_t) ~(PA7_SET_MASK); bool bLedEnabledOld = bLedEnabled; while (true) { handleSwitch(); // check switch state if (bBtnPressed) { leds_on(); } else { leds_off(); } if (bLedEnabledOld != bLedEnabled) { // A long press detected --> confirm with a blink bLedEnabledOld = bLedEnabled; leds_off(); _delay_ms(BUTTON_IGNORE_DURATION_MS / 10); leds_on(); _delay_ms(BUTTON_IGNORE_DURATION_MS / 10); leds_off(); _delay_ms(BUTTON_IGNORE_DURATION_MS); blinkLed(true); // reset the persistent counters } else { if ((bLedEnabled) && (!bBtnPressed)) { blinkLed(false); } } _delay_ms(MAIN_LOOP_SLEEP); } } /** * @brief Switch off all controlled LEDs (PA1, PA2, PA3). * * @note Declared inline for speed (single instruction sequence). */ static inline void leds_off(void) { VPORTA.OUT &= (uint8_t) ~(PA1_SET_MASK | PA2_SET_MASK | PA3_SET_MASK); } /** * @brief Switch on all controlled LEDs (PA1, PA2, PA3). * * @note Declared inline for speed (single instruction sequence). */ static inline void leds_on(void) { VPORTA.OUT |= (PA1_SET_MASK | PA2_SET_MASK | PA3_SET_MASK); } /** * @brief Handle momentary switch input on PA6. TODO: Switch to PA0 * * A press longer than 2 seconds toggles ::bLedEnabled. * Uses simple state and counters for debouncing and long-press detection. */ static void handleSwitch(void) { static uint16_t pressTicks = 0; ///< press duration counter static bool prevPressed = false; ///< previous switch state bool pressed = !(VPORTA.IN & BUTTON_PIN_MASK); // active-low if (pressed) { bBtnPressed = true; if (pressTicks < 0xFFFF) { // prevent overflow pressTicks++; } } else { bBtnPressed = false; pressTicks = 0; } if (prevPressed && pressTicks >= MS_TO_TICKS(BUTTON_LONG_PRESS_DURATION_MS)) { // long press detected → toggle blinking bLedEnabled = !bLedEnabled; } prevPressed = pressed; } /** * @brief LED blink state machine (bike rear light style). * * Normal cycle: * 0: all off, wait 250 ms * 2: LED 1–2 + 7–8 ON, wait 50 ms * 5: all off, wait 100 ms * 7: LED 1–2 + 7–8 ON, wait 50 ms * 10: all off, wait 250 ms * 12: LED 3–6 ON, wait 50 ms * 14: all off, wait 100 ms * 16: LED 3–6 ON, wait 50 ms * 18: all off, wait 250 ms → restart * Special: every 3rd cycle, all LEDs ON for 250 ms */ void blinkLed(bool resetCounters) { // --- precomputed constants --- const uint8_t T50 = MS_TO_TICKS(50); ///< 50 ms in ticks const uint8_t T100 = MS_TO_TICKS(100); ///< 100 ms in ticks const uint8_t T250 = MS_TO_TICKS(250); ///< 250 ms in ticks // --- persistent state --- static uint16_t counter = 0; ///< ticks for current state static uint8_t state = 2; ///< start with first LEDs-on state static uint8_t cycle = 0; ///< cycle counter if (resetCounters) { counter = 0; state = 12; // start with LEDs on cycle = 0; } counter++; switch (state) { case 0: // all LEDs off, wait 250 ms leds_off(); if (counter >= T250) { counter = 0; state = 2; } break; case 2: // LED 1–2 + 7–8 on, wait 50 ms VPORTA.OUT |= (PA1_SET_MASK | PA3_SET_MASK); if (counter >= T50) { counter = 0; state = 5; } break; case 5: // all LEDs off, wait 100 ms leds_off(); if (counter >= T100) { counter = 0; state = 7; } break; case 7: // LED 1–2 + 7–8 on, wait 50 ms VPORTA.OUT |= (PA1_SET_MASK | PA3_SET_MASK); if (counter >= T50) { counter = 0; state = 10; } break; case 10: // all LEDs off, wait 250 ms leds_off(); if (counter >= T250) { counter = 0; state = 12; } break; case 12: // LED 3–6 on, wait 50 ms VPORTA.OUT |= PA2_SET_MASK; if (counter >= T50) { counter = 0; state = 14; } break; case 14: // all LEDs off, wait 100 ms leds_off(); if (counter >= T100) { counter = 0; state = 16; } break; case 16: // LED 3–6 on, wait 50 ms VPORTA.OUT |= PA2_SET_MASK; if (counter >= T50) { counter = 0; state = 18; } break; case 18: // all LEDs off, wait 250 ms leds_off(); if (counter >= T250) { counter = 0; if (++cycle >= 3) { cycle = 0; state = 20; // special all-LEDs-on state } else { state = 0; // restart normal cycle } } break; case 20: // special: all LEDs on for 250 ms VPORTA.OUT |= (PA1_SET_MASK | PA2_SET_MASK | PA3_SET_MASK); if (counter >= T250) { counter = 0; state = 0; // restart normal sequence } break; } }