screen tearing kinda poop

abi_sys/src/lib.rs

@@ -40,13 +40,13 @@ pub fn print(msg: &str) {
     }
 }
 
-pub type SleepAbi = extern "Rust" fn(ticks: u64);
+pub type SleepAbi = extern "Rust" fn(ms: u64);
 
-pub fn sleep(ticks: u64) {
+pub fn sleep(ms: u64) {
     unsafe {
         let ptr = CALL_ABI_TABLE[CallAbiTable::Print as usize];
         let f: SleepAbi = core::mem::transmute(ptr);
-        f(ticks);
+        f(ms);
     }
 }
 

kernel/src/abi.rs

@@ -4,6 +4,7 @@ use abi_sys::{DrawIterAbi, GetKeyAbi, Pixel, PrintAbi, SleepAbi};
 use alloc::boxed::Box;
 use defmt::info;
 use embassy_futures::block_on;
+use embassy_rp::clocks::clk_sys_freq;
 use embassy_time::Timer;
 use embedded_graphics::{
     Drawable,
@@ -26,9 +27,10 @@ pub extern "Rust" fn print(msg: &str) {
     defmt::info!("{:?}", msg);
 }
 
-pub extern "Rust" fn sleep(ticks: u64) {
-    for _ in 0..ticks {
-        for _ in 0..100 {
+pub extern "Rust" fn sleep(ms: u64) {
+    let cycles_per_ms = clk_sys_freq() / 1000;
+    for _ in 0..ms {
+        for _ in 0..cycles_per_ms {
             cortex_m::asm::nop();
         }
     }
@@ -36,10 +38,7 @@ pub extern "Rust" fn sleep(ticks: u64) {
 
 // TODO: maybe return result
 pub extern "Rust" fn draw_iter(pixels: &[Pixel<Rgb565>]) {
-    loop {
-        unsafe { FRAMEBUFFER.draw_iter(pixels.iter().copied()).unwrap() }
-        return;
-    }
+    unsafe { FRAMEBUFFER.draw_iter(pixels.iter().copied()).unwrap() }
 }
 
 pub extern "Rust" fn get_key() -> Option<KeyEvent> {

kernel/src/main.rs

@@ -259,8 +259,10 @@ static mut KEY_CACHE: Queue<KeyEvent, 32> = Queue::new();
 
 async fn get_keys() {
     if let Some(event) = read_keyboard_fifo().await {
-        unsafe {
-            let _ = KEY_CACHE.enqueue(event);
+        if let KeyState::Pressed = event.state {
+            unsafe {
+                let _ = KEY_CACHE.enqueue(event);
+            }
         }
     }
 }

user-apps/calculator/src/main.rs

@@ -2,7 +2,7 @@
 #![no_main]
 
 extern crate alloc;
-use abi::{KeyCode, display::Display, embassy_time, get_key, print};
+use abi::{KeyCode, display::Display, embassy_time, get_key, print, sleep};
 use alloc::{boxed::Box, string::String, vec};
 use core::{panic::PanicInfo, pin::Pin};
 use embedded_graphics::{
@@ -10,7 +10,8 @@ use embedded_graphics::{
     geometry::{Dimensions, Point},
     mono_font::{MonoTextStyle, ascii::FONT_6X10},
     pixelcolor::Rgb565,
-    prelude::RgbColor,
+    prelude::{Primitive, RgbColor, Size},
+    primitives::{PrimitiveStyle, Rectangle},
     text::{Alignment, Text},
 };
 
@@ -28,6 +29,16 @@ pub async fn main() {
     let mut text = vec!['H', 'E', 'L', 'L', 'O'];
 
     loop {
+        // First, clear the text area
+        let text_area = Rectangle::new(
+            display.bounding_box().center() + Point::new(0, 0),
+            Size::new(320, 320),
+        );
+        Rectangle::new(text_area.top_left, text_area.size)
+            .into_styled(PrimitiveStyle::with_fill(Rgb565::BLACK))
+            .draw(&mut display)
+            .unwrap();
+
         Text::with_alignment(
             &text.iter().cloned().collect::<String>(),
             display.bounding_box().center() + Point::new(0, 15),
@@ -37,8 +48,6 @@ pub async fn main() {
         .draw(&mut display)
         .unwrap();
 
-        embassy_time::Timer::after_millis(1000).await;
-
         if let Some(event) = get_key() {
             print("User got event");
             match event.key {
@@ -51,6 +60,7 @@ pub async fn main() {
                 _ => (),
             }
         }
+        sleep(1000)
     }
 }