From 84c3f5421626ac3e86064ef801273e2b69c692d7 Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Thu, 18 Jul 2019 12:19:23 +0200
Subject: [PATCH] Aircon: Better main loop

---
 aircon/firmware/config.h |  2 +-
 aircon/firmware/main.c   | 31 ++++++++++++++++++++++---------
 lib/util.h               |  7 +++++++
 3 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/aircon/firmware/config.h b/aircon/firmware/config.h
index 2c40c0b..af1ea4c 100644
--- a/aircon/firmware/config.h
+++ b/aircon/firmware/config.h
@@ -30,7 +30,7 @@
 
 #define MODBUS_BAUD_RATE 19200
 
-#define MODBUS_DEBUG
+#undef MODBUS_DEBUG
 
 // DS18B20 library parameters
 
diff --git a/aircon/firmware/main.c b/aircon/firmware/main.c
index b4650bf..737aafb 100644
--- a/aircon/firmware/main.c
+++ b/aircon/firmware/main.c
@@ -19,6 +19,7 @@
 #include <string.h>
 
 static void rc_init(void);
+static bool rc_send(char key);
 
 static void clock_init(void)
 {
@@ -106,12 +107,14 @@ static void tick_init(void)
 	systick_interrupt_enable();
 }
 
+#if 0
 static void delay_ms(uint ms)
 {
 	u32 start_ticks = ms_ticks;
 	while (ms_ticks - start_ticks < ms)
 		;
 }
+#endif
 
 static void usart_init(void)
 {
@@ -131,7 +134,6 @@ static void usart_init(void)
 static byte bypass_active;
 static byte fan_pwm;
 
-// FIXME
 static void show_temperature(void)
 {
 	debug_putc('#');
@@ -157,7 +159,6 @@ static void pwm_init(void)
 
 	// 50% PWM for the IR LED
 	timer_set_oc_mode(TIM4, TIM_OC2, TIM_OCM_FORCE_HIGH);	// will be TIM_OCM_PWM1 when transmitting
-	// timer_set_oc_mode(TIM4, TIM_OC2, TIM_OCM_PWM1);	// FIXME
 	timer_set_oc_value(TIM4, TIM_OC2, T4_CYCLE / 2);
 	timer_set_oc_polarity_high(TIM4, TIM_OC2);
 	timer_enable_oc_output(TIM4, TIM_OC2);
@@ -180,17 +181,23 @@ int main(void)
 	pwm_init();
 	rc_init();
 
-	debug_puts("Hello, world!\n");
+	debug_puts("Hello, world! This is Aircon Controller speaking.\n");
 
 	ds_init();
 	modbus_init();
 
-	byte cycles = 0;
+	u32 last_show_temp = 0;
+	u32 last_ds_step = 0;
+
 	for (;;) {
-		debug_led_toggle();
-		delay_ms(100);
-		ds_step();
+		if (ms_ticks - last_ds_step >= 100) {
+			debug_led_toggle();
+			ds_step();
+			last_ds_step = ms_ticks;
+		}
+
 		modbus_loop();
+
 		if (usart_get_flag(USART1, USART_SR_RXNE)) {
 			uint ch = usart_recv(USART1);
 			if (ch == 'B') {
@@ -219,12 +226,17 @@ int main(void)
 				 *	% = pwm*4.389 - 12.723
 				 */
 				timer_set_oc_value(TIM4, TIM_OC1, T4_CYCLE * fan_pwm / 256);
+			} else {
+				rc_send(ch);
 			}
 		}
-		if (cycles++ >= 50) {
-			cycles = 0;
+
+		if (ms_ticks - last_show_temp >= 5000) {
 			show_temperature();
+			last_show_temp = ms_ticks;
 		}
+
+		wait_for_interrupt();
 	}
 
 	return 0;
@@ -341,6 +353,7 @@ static bool rc_send(char key)
 		return false;
 	rc_pending = key;
 	rc_pattern_pos = rc_patterns[s - rc_keys];
+	debug_printf("RC sending: %c", key);
 
 	gpio_clear(GPIOC, GPIO13);
 
diff --git a/lib/util.h b/lib/util.h
index b37c527..e31f7fd 100644
--- a/lib/util.h
+++ b/lib/util.h
@@ -77,6 +77,13 @@ static inline void put_u32_le(byte *p, u32 x)
 	p[0] = x & 0xff;
 }
 
+// CPU instructions not covered by libopencm3
+
+static inline void wait_for_interrupt(void)
+{
+	asm volatile ("wfi");
+}
+
 // util-debug.c
 
 void debug_printf(const char *fmt, ...);
-- 
2.39.5