Fix compilation errors when UART is disabled

main.c

@@ -31,7 +31,9 @@
 #include "driver/gpio.h"
 #include "driver/system.h"
 #include "driver/systick.h"
-#include "driver/uart.h"
+#ifdef ENABLE_UART
+	#include "driver/uart.h"
+#endif
 #include "helper/battery.h"
 #include "helper/boot.h"
 #include "misc.h"
@@ -42,16 +44,17 @@
 #include "ui/menu.h"
 #include "version.h"
 
-void _putchar(char c)
+void _putchar(__attribute__((unused)) char c)
 {
+
+#ifdef ENABLE_UART
 	UART_Send((uint8_t *)&c, 1);
+#endif
+
 }
 
 void Main(void)
 {
-	unsigned int i;
-	BOOT_Mode_t  BootMode;
-
 	// Enable clock gating of blocks we need
 	SYSCON_DEV_CLK_GATE = 0
 		| SYSCON_DEV_CLK_GATE_GPIOA_BITS_ENABLE
@@ -66,11 +69,13 @@ void Main(void)
 
 	SYSTICK_Init();
 	BOARD_Init();
-	UART_Init();
 
 	boot_counter_10ms = 250;   // 2.5 sec
 
+#ifdef ENABLE_UART
+	UART_Init();
 	UART_Send(UART_Version, strlen(UART_Version));
+#endif
 
 	// Not implementing authentic device checks
 
@@ -92,7 +97,7 @@ void Main(void)
 
 	RADIO_SetupRegisters(true);
 
-	for (i = 0; i < ARRAY_SIZE(gBatteryVoltages); i++)
+	for (unsigned int i = 0; i < ARRAY_SIZE(gBatteryVoltages); i++)
 		BOARD_ADC_GetBatteryInfo(&gBatteryVoltages[i], &gBatteryCurrent);
 
 	BATTERY_GetReadings(false);
@@ -101,8 +106,8 @@ void Main(void)
 		AM_fix_init();
 	#endif
 
-	BootMode = BOOT_GetMode();
-	
+	const BOOT_Mode_t  BootMode = BOOT_GetMode();
+
 	if (BootMode == BOOT_MODE_F_LOCK)
 	{
 		gF_LOCK = true;            // flag to say include the hidden menu items
@@ -124,8 +129,9 @@ void Main(void)
 	{	// keys are pressed
 		UI_DisplayReleaseKeys();
 		BACKLIGHT_TurnOn();
-		i = 0;
-		while (i < 50)  // 500ms
+
+		// 500ms
+		for (int i = 0; i < 50;)
 		{
 			i = (GPIO_CheckBit(&GPIOC->DATA, GPIOC_PIN_PTT) && KEYBOARD_Poll() == KEY_INVALID) ? i + 1 : 0;
 			SYSTEM_DelayMs(10);