fw-rust: Handle data residing in the EEPROM

firmware/rust/src/main.rs

@@ -16,6 +16,14 @@ use embedded_hal::{
 use nb::block;
 use panic_halt as _;
 
+#[used]
+#[link_section = ".eeprom"]
+static CONTRAST: u8 = 8;
+
+#[used]
+#[link_section = ".eeprom"]
+static BACKLIGHT: u8 = 1;
+
 // TODO: Use https://github.com/rust-lang/rust/issues/85077 when stabilized
 static SACRED_CHAO: [[u8; 40]; 5] = [
     [
@@ -64,11 +72,35 @@ static ONDERS_ORG: [[u8; 48]; 2] = [
 #[atmega_hal::entry]
 fn main() -> ! {
     interrupt::free(|_cs| {
-        // Get peripherals, pins and delay
+        // Get peripherals, pins, eeprom and delay
         let dp = Peripherals::take().unwrap();
         let pins = pins!(dp);
+        let eeprom = dp.EEPROM;
         let mut delay = Delay::<MHz8>::new();
 
+        // TODO: Wait for completion of previous write
+        // Write address into eeprom address register
+        eeprom
+            .eear
+            .write(|w| unsafe { w.bits(&CONTRAST as *const u8 as u16) });
+        // Start to read from eeprom by setting EERE
+        eeprom.eecr.write(|w| w.eere().set_bit());
+        // Return data from eeprom data register
+        let _contrast = eeprom.eedr.read().bits();
+
+        // TODO: Remove delay when waiting for completion of revious write is done
+        delay.delay_ms(1_u8);
+
+        // TODO: Wait for completion of previous write
+        // Write address into eeprom address register
+        eeprom
+            .eear
+            .write(|w| unsafe { w.bits(&BACKLIGHT as *const u8 as u16) });
+        // Start to read from eeprom by setting EERE
+        eeprom.eecr.write(|w| w.eere().set_bit());
+        // Return data from eeprom data register
+        let _backlight = eeprom.eedr.read().bits();
+
         // Init display backlight
         let tc0 = dp.TC0;
         tc0.tccr0a.write(|w| {