From 24daab9c1705055eb10964840395c5411ce083c3 Mon Sep 17 00:00:00 2001
From: kirbylife <kirbylife@protonmail.com>
Date: Sat, 10 Dec 2022 23:48:27 -0600
Subject: [PATCH] add comments

---
 src/main.rs | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/main.rs b/src/main.rs
index d58ee28..e0f0c18 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,16 +5,30 @@
 use core::arch::asm;
 use core::ptr::{read_volatile, write_volatile};
 
+/*
+PORTC{0..5} Analog
+PORTC6 Reset
+
+PORTB{0..5} Digital {8..13}
+PORTD{0..7} Digital {0..7}
+
+PORTB5 LED_BUILTIN
+ */
+
 const DDRB: *mut u8 = 0x24 as *mut u8;
 const PORTB: *mut u8 = 0x25 as *mut u8;
 
+// ATmega328p cycle speed
 const CPU_SPEED: u32 = 16_000_000;
 
 #[no_mangle]
 pub extern "C" fn main() -> ! {
+    // Set all the B pins on OUTPUT mode
     unsafe { write_volatile(DDRB, 0b11111111) };
 
     loop {
+        // if pin[5] == 1: 1^1 = 0
+        // if pin[5] == 0: 0^1 = 1
         let mut portb_value = unsafe { read_volatile(PORTB) };
         portb_value = portb_value ^ (1 << 5);
         unsafe { write_volatile(PORTB, portb_value) };