car_fmw: implementation of periodic forward and backward engine rotation

car_fmw/src/car_engine.h

@@ -0,0 +1,53 @@
+#pragma once
+
+#include "stm32f4_discovery.h"
+#include "stm32f4xx_conf.h"
+
+//#define CAR_ENGINE_ENABLE
+
+#define CAR_ENGINE_GPIO_PORT_CLOCK RCC_AHB1Periph_GPIOB
+#define CAR_ENGINE_GPIO_PORT GPIOB
+#define CAR_ENGINE_ENABLE_PIN GPIO_Pin_4
+#define CAR_ENGINE_DIRECTION_FORWARD_PIN GPIO_Pin_5
+#define CAR_ENGINE_DIRECTION_BACKWARD_PIN GPIO_Pin_6
+
+inline void engine_init(void)
+{
+    GPIO_InitTypeDef GPIO_InitStructure;
+    RCC_AHB1PeriphClockCmd(CAR_ENGINE_GPIO_PORT_CLOCK, ENABLE);
+    GPIO_InitStructure.GPIO_Pin = CAR_ENGINE_ENABLE_PIN
+        | CAR_ENGINE_DIRECTION_FORWARD_PIN
+        | CAR_ENGINE_DIRECTION_BACKWARD_PIN;
+    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
+    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
+    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
+    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
+    GPIO_Init(CAR_ENGINE_GPIO_PORT, &GPIO_InitStructure);
+}
+
+inline void engine_stop(void)
+{
+    GPIO_ResetBits(CAR_ENGINE_GPIO_PORT, 0
+            | CAR_ENGINE_DIRECTION_BACKWARD_PIN
+            | CAR_ENGINE_ENABLE_PIN
+            | CAR_ENGINE_DIRECTION_FORWARD_PIN);
+}
+
+#ifdef CAR_ENGINE_ENABLE
+inline void engine_forward(void)
+{
+    engine_stop();
+    GPIO_SetBits(CAR_ENGINE_GPIO_PORT, CAR_ENGINE_ENABLE_PIN);
+    GPIO_SetBits(CAR_ENGINE_GPIO_PORT, CAR_ENGINE_DIRECTION_FORWARD_PIN);
+}
+
+inline void engine_backward(void)
+{
+    engine_stop();
+    GPIO_SetBits(CAR_ENGINE_GPIO_PORT, CAR_ENGINE_ENABLE_PIN);
+    GPIO_SetBits(CAR_ENGINE_GPIO_PORT, CAR_ENGINE_DIRECTION_BACKWARD_PIN);
+}
+#else
+#define engine_forward(...);
+#define engine_backward(...);
+#endif // CAR_ENGINE_ENABLE

car_fmw/src/main.c

@@ -1,4 +1,5 @@
 #include "car_leds.h"
+#include "car_engine.h"
 #include "delay.h"
 
 int main(void)
@@ -11,21 +12,31 @@ int main(void)
      */
 
     leds_init();
+    engine_init();
 
+    const int DELAY = 0x3FFFFF;
     while (1)
     {
         led_set(LED_GREEN, true);
-        Delay(0x3FFFFF);
+        Delay(DELAY);
+
+        engine_forward();
         led_set(LED_ORANGE, true);
-        Delay(0x3FFFFF);
+        Delay(DELAY);
+
+        engine_stop();
         led_set(LED_RED, true);
-        Delay(0x3FFFFF);
+        Delay(DELAY);
+
+        engine_backward();
         led_set(LED_BLUE, true);
-        Delay(0x7FFFFF);
+        Delay(DELAY);
+
+        engine_stop();
         led_set(LED_GREEN, false);
         led_set(LED_ORANGE, false);
         led_set(LED_RED, false);
         led_set(LED_BLUE, false);
-        Delay(0xFFFFFF);
+        Delay(DELAY);
     }
 }