fw-rust: Create Lcd struct to handle the screen

To improve screen handling create the `Lcd` struct and implement some
first helper functions.

firmware/rust/src/main.rs

@@ -5,7 +5,7 @@ use atmega_hal::{
     clock::MHz8,
     delay::Delay,
     pins,
-    port::{mode::Output, Pin, PB0},
+    port::{mode::Output, Pin, PB0, PB1},
     spi::{DataOrder, SerialClockRate, Settings, Spi},
     Peripherals,
 };
@@ -68,78 +68,134 @@ const ONDERS_ORG: [[u8; 48]; 2] = [
     ],
 ];
 
-fn clear_screen(spi: &mut Spi, cd: &mut Pin<Output, PB0>) {
+pub struct Lcd {
+    spi: Spi,
+    cd: Pin<Output, PB0>,
+    rst: Pin<Output, PB1>,
+}
+
+impl Lcd {
+    fn init(&mut self, contrast: u8) {
+        let mut delay = Delay::<MHz8>::new();
+
+        // TODO: Test if delay is really needed
+        delay.delay_ms(1_u8);
+        self.rst.set_high();
+        // TODO: Try to reduce delay to a minimum
+        delay.delay_ms(1_u8);
+
+        block!(self.spi.send(0x40)).unwrap(); // (6)  Set Scroll Line: Display start line 0
+        block!(self.spi.send(0xA1)).unwrap(); // (13) Set SEG direction: SEG reverse
+        block!(self.spi.send(0xC0)).unwrap(); // (14) Set COM direction: Normal COM0 - COM63
+                                              // block!(spi.send(0xA4)).unwrap(); // (10) Set All Pixel On: Disable -> Set All Pixel to ON */
+        block!(self.spi.send(0xA6)).unwrap(); // (11) Set Inverse Display: Display inverse off
+        block!(self.spi.send(0xA2)).unwrap(); // (17) Set LCD Bias Ratio: Set Bias 1/9 (Duty 1/65)
+        block!(self.spi.send(0x2F)).unwrap(); // (5)  Set Power Control: Booster, Regulator and Follower on
+        block!(self.spi.send(0x27)).unwrap(); // (8)  Set VLCD Resistor Ratio: Set Contrast
+                                              // block!(spi.send(0xEE)).unwrap(); // (18) Reset Cursor Update Mode
+        block!(self.spi.send(0x81)).unwrap(); // (9)  Set Electronic Volume: Set Contrast
+        block!(self.spi.send(contrast)).unwrap(); // (9)  Set Electronic Volume: Set Contrast
+                                                  // block!(spi.send(0xFA)).unwrap(); // (25) Set Adv. Program Control 0: Set Temperature compensation curve to -0.11%/°C
+                                                  // block!(spi.send(0x90)).unwrap(); // (25) Set Adv. Program Control 0: Set Temperature compensation curve to -0.11%/°C
+        block!(self.spi.send(0xAF)).unwrap(); // (12) Set Display Enable: Display on
+
+        // TODO: This delay fixes issues, try find a better solution
+        delay.delay_ms(1_u8);
+    }
+
+    fn move_cursor(&mut self, segment: u8, page: u8) {
+        assert!(segment < 102);
+        assert!(page < 8);
+
+        block!(self.spi.send(0x0F & segment)).unwrap();
+        block!(self.spi.send(0x10 + (segment >> 4))).unwrap();
+        block!(self.spi.send(0xB0 + page)).unwrap();
+    }
+
+    fn clear(&mut self) {
         let mut delay = Delay::<MHz8>::new();
 
         for page in 0..8 {
-        block!(spi.send(0x00)).unwrap();
+            self.move_cursor(0, page as u8);
-        block!(spi.send(0x10)).unwrap();
-        block!(spi.send(0xB0 + page)).unwrap();
 
             // TODO: This delay fixes issues, try find a better solution
             delay.delay_ms(1_u8);
-        cd.set_high();
+            self.cd.set_high();
 
             for _ in 0..102 {
-            block!(spi.send(0x00)).unwrap();
+                block!(self.spi.send(0x00)).unwrap();
             }
 
             // TODO: This delay fixes issues, try find a better solution
             delay.delay_ms(1_u8);
-        cd.set_low();
+            self.cd.set_low();
+        }
+    }
+
+    fn screen(&mut self, screen: &Screens) {
+        self.clear();
+
+        match screen {
+            Screens::Splash(splash) => splash.draw(self),
+        }
     }
 }
 
-fn draw_splash(spi: &mut Spi, cd: &mut Pin<Output, PB0>) {
+pub trait Draw {
-    clear_screen(spi, cd);
+    fn draw(&self, lcd: &mut Lcd);
+}
 
+struct SplashScreen;
+
+impl Draw for SplashScreen {
+    fn draw(&self, lcd: &mut Lcd) {
         let mut delay = Delay::<MHz8>::new();
 
         for (i, page) in SACRED_CHAO.iter().enumerate() {
-        block!(spi.send(0x0F)).unwrap();
+            lcd.move_cursor(31, 1 + i as u8);
-        block!(spi.send(0x11)).unwrap();
-        block!(spi.send(0xB1 + i as u8)).unwrap();
 
             // TODO: This delay fixes issues, try find a better solution
             delay.delay_ms(1_u8);
-        cd.set_high();
+            lcd.cd.set_high();
 
             for segment in page {
-            block!(spi.send(*segment)).unwrap();
+                block!(lcd.spi.send(*segment)).unwrap();
             }
 
             // TODO: This delay fixes issues, try find a better solution
             delay.delay_ms(1_u8);
-        cd.set_low();
+            lcd.cd.set_low();
         }
 
         for (i, page) in ONDERS_ORG.iter().enumerate() {
-        block!(spi.send(0x0A)).unwrap();
+            lcd.move_cursor(27, 6 + i as u8);
-        block!(spi.send(0x11)).unwrap();
-        block!(spi.send(0xB6 + i as u8)).unwrap();
 
             // TODO: This delay fixes issues, try find a better solution
             delay.delay_ms(1_u8);
-        cd.set_high();
+            lcd.cd.set_high();
 
             for segment in page {
-            block!(spi.send(*segment)).unwrap();
+                block!(lcd.spi.send(*segment)).unwrap();
             }
 
             // TODO: This delay fixes issues, try find a better solution
             delay.delay_ms(1_u8);
-        cd.set_low();
+            lcd.cd.set_low();
         }
+    }
+}
+
+enum Screens {
+    Splash(SplashScreen),
 }
 
 #[atmega_hal::entry]
 fn main() -> ! {
     interrupt::free(|_cs| {
-        // Get peripherals, pins, eeprom and delay
+        // Get peripherals, pins and eeprom
         let dp = Peripherals::take().unwrap();
         let pins = pins!(dp);
         let eeprom = Eeprom::new(dp.EEPROM);
-        let mut delay = Delay::<MHz8>::new();
 
         // Get contrast and backlight from EEPROM
         let contrast = eeprom.read_value(&CONTRAST);
@@ -162,7 +218,7 @@ fn main() -> ! {
         pins.pd5.into_output();
 
         // Init SPI
-        let (mut spi, _) = Spi::new(
+        let (spi, _) = Spi::new(
             dp.SPI,
             pins.pb5.into_output(),
             pins.pb3.into_output(),
@@ -179,27 +235,19 @@ fn main() -> ! {
         );
 
         // Init LCD
-        let mut lcd_cd = pins.pb0.into_output();
+        let mut lcd = Lcd {
-        let mut lcd_rst = pins.pb1.into_output();
+            spi,
-        // TODO: Test if delay is really needed
+            cd: pins.pb0.into_output(),
-        delay.delay_ms(1_u8);
+            rst: pins.pb1.into_output(),
-        lcd_rst.set_high();
+        };
-        // TODO: Try to reduce delay to a minimum
+        lcd.init(contrast);
-        delay.delay_ms(5_u8);
 
-        block!(spi.send(0x40)).unwrap(); // (6)  Set Scroll Line: Display start line 0
+        // Create screen
-        block!(spi.send(0xA1)).unwrap(); // (13) Set SEG direction: SEG reverse
+        // TODO: This should use volatile and probably be somehow globally accessible
-        block!(spi.send(0xC0)).unwrap(); // (14) Set COM direction: Normal COM0 - COM63
+        let screen = Screens::Splash(SplashScreen);
-        block!(spi.send(0xA6)).unwrap(); // (11) Set Inverse Display: Display inverse off
-        block!(spi.send(0xA2)).unwrap(); // (17) Set LCD Bias Ratio: Set Bias 1/9 (Duty 1/65)
-        block!(spi.send(0x2F)).unwrap(); // (5)  Set Power Control: Booster, Regulator and Follower on
-        block!(spi.send(0x27)).unwrap(); // (8)  Set VLCD Resistor Ratio: Set Contrast
-        block!(spi.send(0x81)).unwrap(); // (9)  Set Electronic Volume: Set Contrast
-        block!(spi.send(contrast)).unwrap(); // (9)  Set Electronic Volume: Set Contrast
-        block!(spi.send(0xAF)).unwrap(); // (12) Set Display Enable: Display on
 
         // Draw splash screen
-        draw_splash(&mut spi, &mut lcd_cd);
+        lcd.screen(&screen);
     });
 
     #[allow(clippy::empty_loop)]