From 817776d7358e48836532fc1477e01857fe76de97 Mon Sep 17 00:00:00 2001
From: finga <finga@onders.org>
Date: Fri, 4 Mar 2022 13:17:18 +0100
Subject: [PATCH] fw-rust: Initialize the LCD display

Send commands via SPI to the LCD display to initialize and configure
it.
---
 firmware/rust/src/main.rs | 33 ++++++++++++++++++++++++++++++---
 1 file changed, 30 insertions(+), 3 deletions(-)

diff --git a/firmware/rust/src/main.rs b/firmware/rust/src/main.rs
index bf1f68b..38569cb 100644
--- a/firmware/rust/src/main.rs
+++ b/firmware/rust/src/main.rs
@@ -2,12 +2,18 @@
 #![no_main]
 
 use atmega_hal::{
+    clock::MHz8,
+    delay::Delay,
     pins,
     spi::{DataOrder, SerialClockRate, Settings, Spi},
     Peripherals,
 };
 use avr_device::interrupt;
-use embedded_hal::spi::{Mode, Phase, Polarity};
+use embedded_hal::{
+    blocking::delay::DelayMs,
+    spi::{FullDuplex, Mode, Phase, Polarity},
+};
+use nb::block;
 use panic_halt as _;
 
 #[atmega_hal::entry]
@@ -15,9 +21,10 @@ fn main() -> ! {
     // Disable interrupts when initializing
     interrupt::disable();
 
-    // Get peripherals and pins
+    // Get peripherals, pins and delay
     let dp = Peripherals::take().unwrap();
     let pins = pins!(dp);
+    let mut delay = Delay::<MHz8>::new();
 
     // Init display backlight
     let tc0 = dp.TC0;
@@ -37,7 +44,7 @@ fn main() -> ! {
     pins.pd5.into_output();
 
     // Init SPI
-    let (_, _) = Spi::new(
+    let (mut spi, _) = Spi::new(
         dp.SPI,
         pins.pb5.into_output(),
         pins.pb3.into_output(),
@@ -53,6 +60,26 @@ fn main() -> ! {
         },
     );
 
+    // Init LCD
+    let _lcd_cd = pins.pb0.into_output();
+    let mut lcd_rst = pins.pb1.into_output();
+    // TODO: Test if delay is really needed
+    delay.delay_ms(1_u8);
+    lcd_rst.set_high();
+    // TODO: Try to reduce delay to a minimum
+    delay.delay_ms(5_u8);
+
+    block!(spi.send(0x40)).unwrap(); // (6)  Set Scroll Line: Display start line 0
+    block!(spi.send(0xA1)).unwrap(); // (13) Set SEG direction: SEG reverse
+    block!(spi.send(0xC0)).unwrap(); // (14) Set COM direction: Normal COM0 - COM63
+    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(0x08)).unwrap(); // (9)  Set Electronic Volume: Set Contrast // TODO: Use EEPROM
+    block!(spi.send(0xAF)).unwrap(); // (12) Set Display Enable: Display on
+
     // Enable interrupts
     unsafe { interrupt::enable() };