From bf678fca8282e7ba2e2062933ab96a99181f4a40 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Franti=C5=A1ek=20Boh=C3=A1=C4=8Dek?=
 <fandabohacek@gmail.com>
Date: Tue, 20 Dec 2022 23:16:33 +0100
Subject: [PATCH] feat: add eeprom support

---
 src/eeprom.rs     | 61 +++++++++++++++++++++++++++++++++++++++++++++++
 src/entrypoint.rs | 23 +++++++++++++++++-
 2 files changed, 83 insertions(+), 1 deletion(-)
 create mode 100644 src/eeprom.rs

diff --git a/src/eeprom.rs b/src/eeprom.rs
new file mode 100644
index 0000000..9dfa1ef
--- /dev/null
+++ b/src/eeprom.rs
@@ -0,0 +1,61 @@
+pub struct Eeprom {
+    eeprom: avr_device::atmega8::EEPROM,
+}
+
+impl Eeprom {
+    pub fn new(ep: avr_device::atmega8::EEPROM) -> Eeprom {
+        Eeprom {
+            eeprom: ep
+        }
+    }
+
+    fn wait_until_write(&self) {
+        while self.eeprom.eecr.read().eewe().bit_is_set() {}
+    }
+
+    pub fn read(&self, address: u16, data: &mut [u8]) {
+        let mut address = address;
+        for i in 0..data.len() {
+            let byte = self.read_byte(address);
+            data[i] = byte;
+            address += 1;
+        }
+    }
+
+    pub fn write(&self, address: u16, data: &[u8]) {
+        let mut address = address;
+        for byte in data.iter() {
+            self.write_byte(address, *byte);
+            address += 1;
+        }
+    }
+
+    pub fn read_byte(&self, address: u16) -> u8 {
+        self.wait_until_write();
+
+        self.eeprom.eear.write(|w| unsafe {
+            w.bits(address)
+        });
+
+        self.eeprom.eecr.write(|w| w.eere().set_bit());
+        self.eeprom.eedr.read().bits()
+    }
+
+    pub fn write_byte(&self, address: u16, data: u8) {
+        self.wait_until_write();
+
+        self.eeprom.eear.write(|w| unsafe {
+            w.bits(address)
+        });
+        self.eeprom.eedr.write(|w| unsafe {
+            w.bits(data)
+        });
+
+        self.eeprom.eecr.write(|w|
+            w
+                .eemwe().set_bit()
+                .eewe().clear_bit());
+
+        self.eeprom.eecr.write(|w|  w.eewe().set_bit());
+    }
+}
diff --git a/src/entrypoint.rs b/src/entrypoint.rs
index 5d05633..c4f0520 100644
--- a/src/entrypoint.rs
+++ b/src/entrypoint.rs
@@ -1,6 +1,12 @@
 #![no_std]
 #![no_main]
 
+// TODO: seeds to eeprom
+//
+
+extern crate avr_device;
+
+mod eeprom;
 mod animation;
 mod button;
 mod filled_seven_segment;
@@ -78,8 +84,23 @@ fn main() -> ! {
     let btn_confirm = button::Button::create(in_confirm, false);
     // PERIPHERALS END
 
+
+    // load seeds from eeprom
+    let ep = eeprom::Eeprom::new(dp.EEPROM);
+    let mut seeds = [0u8; 3];
+    ep.read(0, &mut seeds);
+    if seeds[0] == 0 && seeds[1] == 0 && seeds[2] == 0 {
+        seeds[0] = 125;
+        seeds[1] = 139;
+        seeds[2] = 45;
+    }
+
     // RNG
-    let rng = rng::Rng::init(123, 111, 45);
+    let mut rng = rng::Rng::init(seeds[0], seeds[1], seeds[2]);
+
+    // write new seeds
+    let next_seeds = [rng.take_u8(), rng.take_u8(), rng.take_u8()];
+    ep.write(0, &next_seeds);
 
     // GAME
     let mut game = Game {
-- 
2.48.1