add blink pwm code

Core/Src/main.c

@@ -97,6 +97,17 @@ int main(void)
   /* USER CODE BEGIN WHILE */
     while (1)
     {
+        for (int i=0; i<2000; i++)
+        {
+            HAL_GPIO_TogglePin(LED1_GPIO_Port, LED1_Pin);
+            for (int j=0; j<i; j++)
+            {
+            }
+            HAL_GPIO_TogglePin(LED1_GPIO_Port, LED1_Pin);
+            for (int j=2000; j>i; j--)
+            {
+            }
+        }
     /* USER CODE END WHILE */
 
     /* USER CODE BEGIN 3 */

Makefile

@@ -40,7 +40,6 @@ Core/Src/main.c \
 Core/Src/stm32f1xx_it.c \
 Core/Src/stm32f1xx_hal_msp.c \
 Drivers/STM32F1xx_HAL_Driver/Src/stm32f1xx_hal_gpio_ex.c \
-Drivers/STM32F1xx_HAL_Driver/Src/stm32f1xx_hal_i2c.c \
 Drivers/STM32F1xx_HAL_Driver/Src/stm32f1xx_hal_tim.c \
 Drivers/STM32F1xx_HAL_Driver/Src/stm32f1xx_hal_tim_ex.c \
 Drivers/STM32F1xx_HAL_Driver/Src/stm32f1xx_hal_uart.c \