diff --git a/src/main.cpp b/src/main.cpp
index 581ef7d..5c71739 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -4,6 +4,46 @@
 
 #include <MFRC522v2.h>
 
-__attribute__((noreturn)) int main() {
+#include "Pinout.h"
 
+__attribute__((noreturn)) int main() {
+	pinMode(pin_DBG_LED_1, OUTPUT);
+	pinMode(pin_DBG_LED_2, OUTPUT);
+
+	pinMode(pin_Reg_en, OUTPUT);
+	pinMode(pin_Audio_Amp_enable, OUTPUT);
+	pinMode(pin_Audio_AMP_GAIN_EN, OUTPUT);
+
+	pinMode(pin_NFC1_RST, OUTPUT);
+	pinMode(pin_LCD_RST, OUTPUT);
+
+	/* Preemptively disable what we can before the regulator is ON. */
+	digitalWrite(pin_Audio_Amp_enable, LOW);
+	digitalWrite(pin_NFC1_RST, LOW);
+	digitalWrite(pin_LCD_RST, LOW);
+
+	pinMode(pin_BAT_SNS, INPUT);
+	/*
+	 * Voltage divider ratio is 1.5 and analog input has 10 significant bits.
+	 * Which gives us 0-1023 <=> 0V-4.95V, so 650 is a measure of 3.14V.
+	 * This is quite low, but there's a voltage drop because of the diode, and
+	 * we don't want to be at the very end of the battery's charge anyway.
+	 * Let's be conservative.
+	 */
+	if (analogRead(pin_BAT_SNS) < 650) { /* TODO: Low battery handling */ }
+
+	digitalWrite(pin_Reg_en, HIGH);
+	/*
+	 * System is powered up after this point.
+	 */
+
+	Serial.begin(115200);
+	Serial.println("# System is powered up, running set-up.");
+
+	/* TODO: Setups once module structure is up. */
+
+	/* Main loop */
+	while (true) {
+
+	}
 }