From ea54b8a9fb1b8dce528a1465a9cc73ad0ffa0b90 Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Tue, 26 Jun 2018 00:41:24 +0200
Subject: [PATCH] We have a working timer interrupt!

---
 Src/main.c         |  9 +++++----
 Src/stm32f1xx_it.c | 12 ++++++++++++
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/Src/main.c b/Src/main.c
index de59f78..57349e4 100644
--- a/Src/main.c
+++ b/Src/main.c
@@ -124,6 +124,10 @@ int main(void)
   display_init();
   usb_start(&usb);
 
+  LL_TIM_EnableCounter(TIM4);
+  LL_TIM_EnableIT_UPDATE(TIM4);
+  LL_TIM_GenerateEvent_UPDATE(TIM4);
+
   /* USER CODE END 2 */
 
   /* Infinite loop */
@@ -133,10 +137,7 @@ int main(void)
   {
     debug_printf("Counter = %d\n", cnt);
     display_counter(cnt);
-    LL_GPIO_SetOutputPin(LED_GPIO_Port, LED_Pin);
-    LL_mDelay(500);
-    LL_GPIO_ResetOutputPin(LED_GPIO_Port, LED_Pin);
-    LL_mDelay(500);
+    LL_mDelay(1000);
     cnt++;
 
   /* USER CODE END WHILE */
diff --git a/Src/stm32f1xx_it.c b/Src/stm32f1xx_it.c
index a02f001..67ae5fe 100644
--- a/Src/stm32f1xx_it.c
+++ b/Src/stm32f1xx_it.c
@@ -36,6 +36,8 @@
 #include "stm32f1xx_it.h"
 
 /* USER CODE BEGIN 0 */
+#include "util.h"
+#include "app.h"
 
 /* USER CODE END 0 */
 
@@ -226,6 +228,16 @@ void USB_LP_CAN1_RX0_IRQHandler(void)
 void TIM4_IRQHandler(void)
 {
   /* USER CODE BEGIN TIM4_IRQn 0 */
+  if (LL_TIM_IsActiveFlag_UPDATE(TIM4))
+    {
+      static byte led_state;
+      if (led_state)
+	LL_GPIO_SetOutputPin(LED_GPIO_Port, LED_Pin);
+      else
+	LL_GPIO_ResetOutputPin(LED_GPIO_Port, LED_Pin);
+      led_state ^= 1;
+      LL_TIM_ClearFlag_UPDATE(TIM4);
+    }
 
   /* USER CODE END TIM4_IRQn 0 */
   /* USER CODE BEGIN TIM4_IRQn 1 */
-- 
2.39.2