simplified main loop with coroutines

fw/main.c

@@ -33,6 +33,26 @@ static inline bool timer_expired(struct timer *t)
 }
 
 
+// Button
+struct button {
+	bool now, prev;
+};
+
+static inline void button_init(struct button *btn, bool pullup)
+{
+	btn->now = btn->prev = pullup;
+}
+
+static inline void button_update(struct button *btn, bool state)
+{
+	btn->prev = btn->now;
+	btn->now = state;
+}
+
+#define button_rising(btn) ((btn).now == true && (btn).prev == false)
+#define button_falling(btn) ((btn).now == false && (btn).prev == true)
+
+
 /* ------------------------------ Global State ------------------------------ */
 u8g2_t *u8g2;                   // Display state
 int16_t encoder;                // Rotary encoder counter
@@ -45,7 +65,6 @@ uint16_t vbus_mv;               // USB bus voltage in mV
 uint16_t current_ma;            // USB bus current to the heater in mA
 uint16_t power;                 // Current power provided to the heater
 uint16_t duty;                  // Current mosfet driver duty cycle (0-100%)
-bool pwm = false;               // PWM status (on-off)
 bool enabled = false;           // Power electronics enabled
 
 
@@ -493,10 +512,69 @@ static inline void update_tip_and_vcc(void)
 }
 
 
+// coroutine to draw the "main" ui which draws the current tip temperature, power
+// pwm state, etc.
+coro_state_t cs_ui;
+coroutine c_draw_main_ui(coro_state_t *state)
+{
+	static struct timer t;
+	coro_begin(state);
+
+	for(;;) {
+		// Wait for the next frame, roughly 30 fps
+		timer_set(&t, 33);
+		coro_wait_until(state, timer_expired(&t));
+
+		// Draw UI
+		u8g2_ClearBuffer(u8g2);
+		u8g2_SetFont(u8g2, u8g2_font_5x8_tr);
+		draw_temp(u8g2, x_off+0, y_off+0, tip_temp_c, true);
+		u8g2_DrawStr(u8g2, x_off+32, y_off+6, "A:");
+		u8g2_DrawStr(u8g2, x_off+42, y_off+6, u16toa((current_ma+500)/1000));
+		u8g2_DrawStr(u8g2, x_off+60, y_off+6, "V:");
+		u8g2_DrawStr(u8g2, x_off+70, y_off+6, u16toa((vbus_mv+500)/1000));
+		uint8_t p = (power*100)/pd_profile.set_power;
+		uint8_t w = (uint16_t)(p*54)/100;
+		u8g2_DrawBox(u8g2, x_off+42, y_off+14, w, 5);
+	}
+
+	coro_end();
+}
+
+
+// coroutine to update the tip temperature, vcc and compute the new pid value
+// this has to be called periodically but only with pwm disabled
+coro_state_t cs_duty;
+coroutine c_update_duty(coro_state_t *state)
+{
+	static struct timer t;
+	coro_begin(state);
+
+	for(;;) {
+		timer_set(&t, 50);
+		coro_wait_until(state, timer_expired(&t));
+
+		pwm_set(0);
+		Delay_Ms(TURN_OFF_DELAY);
+		update_tip_and_vcc();
+		if (enabled) {
+			duty = pid((int16_t)pd_profile.set_temp - tip_temp_c, pd_profile.max_duty);
+		} else {
+			duty = 0;
+		}
+	}
+
+	coro_end();
+}
+
+
 __attribute__((noreturn)) int main(void)
 {
 	setup();
 
+	coro_init(&cs_ui);
+	coro_init(&cs_duty);
+
 	u8g2_ClearBuffer(u8g2);
 	u8g2_SetFont(u8g2, u8g2_font_5x8_tr);
 	u8g2_DrawStr(u8g2, x_off+0, y_off+7, "Negotiating...");
@@ -539,33 +617,21 @@ __attribute__((noreturn)) int main(void)
 		STATE_MENU,
 		STATE_HEATING,
 	} state = STATE_MENU;
+
+	/* ============================== Main Loop =============================== */
+	struct button btn;
+	button_init(&btn, true);
 	for (;;) {
-		u32 start = funSysTick32();
+		button_update(&btn, funDigitalRead(PIN_BTN));
 
-		u8g2_ClearBuffer(u8g2);
-		u8g2_SetFont(u8g2, u8g2_font_5x8_tr);
-
-		static uint8_t count = 0; // Loop cycles with PWM on
-		static s32 elapsed = 0;
-		static bool prev_btn = true;
-		bool btn = funDigitalRead(PIN_BTN);
-
-		if (has_pd) {
 		update_power_and_temperature();
 
-			// Update the tip temperature only when the PWM is not running
+		c_update_duty(&cs_duty);
-			if (!pwm || !enabled) {
-				Delay_Ms(TURN_OFF_DELAY);
-				update_tip_and_vcc();
-				if (enabled) {
-					duty = pid((int16_t)pd_profile.set_temp - tip_temp_c, pd_profile.max_duty);
-				} else {
-					duty = 0;
-				}
-			}
 
 		switch (state) {
 		case STATE_MENU:
+			u8g2_ClearBuffer(u8g2);
+			u8g2_SetFont(u8g2, u8g2_font_5x8_tr);
 			u8g2_DrawStr(u8g2, x_off+0, y_off+7, "TEMP:");
 			u8g2_DrawStr(u8g2, x_off+25, y_off+7, u8g2_u16toa(pd_profile.set_temp, 4));
 
@@ -576,53 +642,31 @@ __attribute__((noreturn)) int main(void)
 				if (pd_profile.set_temp > MAX_TIP_SET_TEMP) pd_profile.set_temp = MAX_TIP_SET_TEMP;
 			}
 
-				if (btn == 0 && prev_btn == 1) {
+			if (button_falling(btn)) {
 				state = STATE_HEATING;
 				enabled = false;
 			}
 			break;
 		case STATE_HEATING:
-				// Draw UI
+			c_draw_main_ui(&cs_ui);
-				draw_temp(u8g2, x_off+0, y_off+0, tip_temp_c, true);
-				u8g2_DrawStr(u8g2, x_off+32, y_off+6, "A:");
-				u8g2_DrawStr(u8g2, x_off+42, y_off+6, u16toa((current_ma+500)/1000));
-				u8g2_DrawStr(u8g2, x_off+60, y_off+6, "V:");
-				u8g2_DrawStr(u8g2, x_off+70, y_off+6, u16toa((vbus_mv+500)/1000));
-				uint8_t p = (power*100)/pd_profile.set_power;
-				uint8_t w = (uint16_t)(p*54)/100;
-				u8g2_DrawBox(u8g2, x_off+42, y_off+14, w, 5);
 
 			if (enabled) {
 				funDigitalWrite(PIN_12V, 1);
 
-					if (count > CYCLES_PER_MEASURE) {
-						pwm = false;
-						count = 0;
-					} else {
-						pwm = true;
-						count++;
-					}
-
 				// Safety logic
 				if (current_ma > pd_profile.max_current + pd_profile.max_current/10) {
-						pwm = false;
+					enabled = false;
 				}
 				if (temp_c > MAX_BOARD_TEMP) {
 					enabled = false;
-						pwm = false;
 				}
 				if (tip_temp_c > MAX_TIP_TEMP) {
 					enabled = false;
-						pwm = false;
 				}
 
-					if (pwm) {
 				const uint16_t tim_max = FUNCONF_SYSTEM_CORE_CLOCK / PWM_FREQ_HZ - 1;
 				pwm_set(((u32)duty*tim_max)/100);
 				u8g2_DrawBox(u8g2, x_off+92, y_off+0, 4, 4);
-					} else {
-						pwm_set(0);
-					}
 			} else {
 				funDigitalWrite(PIN_12V, 0);
 			}
@@ -635,7 +679,7 @@ __attribute__((noreturn)) int main(void)
 			}
 
 			// Check button to toggle enable
-				if (btn == 0 && prev_btn == 1) {
+			if (button_falling(btn)) {
 				enabled = !enabled;
 				if (enabled) {
 					pwm_on();
@@ -645,18 +689,6 @@ __attribute__((noreturn)) int main(void)
 			}
 			break;
 		}
-		} else {
-			// No PD capability, just display a message
-			u8g2_DrawStr(u8g2, x_off+0, y_off+7, "NO PD");
-		}
-
 		u8g2_SendBuffer(u8g2);
-
-		prev_btn = btn;
-
-		elapsed = funSysTick32() - start;
-		if (elapsed > 0 && elapsed < Ticks_from_Ms(FRAME_TIME_MS)) {
-			DelaySysTick(Ticks_from_Ms(FRAME_TIME_MS) - elapsed);
-		}
 	}
 }