add PCA9685 testing, add support for one-time run and cleanup functions

Core/Inc/PCA9685.h

@@ -0,0 +1,2 @@
+void PCA9685_run_test(void);
+void PCA9685_cleanup(void);

Core/Inc/lcd.h

@@ -1,6 +1,8 @@
 #ifndef __LCD
 #define __LCD
 
+#include <stdint.h>
+
 #define DISPLAY_RS  ((uint16_t) (0x1U << 7))
 #define DISPLAY_RW  ((uint16_t) (0x1U << 10))
 #define DISPLAY_ENA ((uint16_t) (0x1U << 11))

Core/Inc/stm32f4xx_hal_conf.h

@@ -53,7 +53,7 @@
 /* #define HAL_SRAM_MODULE_ENABLED */
 /* #define HAL_SDRAM_MODULE_ENABLED */
 /* #define HAL_HASH_MODULE_ENABLED */
-/* #define HAL_I2C_MODULE_ENABLED */
+#define HAL_I2C_MODULE_ENABLED
 /* #define HAL_I2S_MODULE_ENABLED */
 /* #define HAL_IWDG_MODULE_ENABLED */
 /* #define HAL_LTDC_MODULE_ENABLED */