Screen control

lwcpu/src/lib.rs

@@ -7,8 +7,9 @@ pub const BASE_POINTER           : u32 = 0x1000_0000;
 pub const NUMBER_DISPLAY_OFFSET  : u32 = 0x00;
 pub const RANDOM_NUMBER_OFFSET   : u32 = 0x04;
 pub const BUTTONS_OFFSET         : u32 = 0x08;
-pub const TEXT_DISPLAY_OFFSET    : u32 = 0x0C;
+pub const TEXT_DISPLAY_OFFSET    : u32 = 0x28;
 pub const KEYBOARD_OFFSET        : u32 = 0x10;
+pub const SCREEN_CONTROL_OFFSET  : u32 = 0x20;
 pub const SCREEN_OFFSET          : u32 = 0x80;
 
 pub const NUMBER_DISPLAY_POINTER : *mut u32 = (BASE_POINTER + NUMBER_DISPLAY_OFFSET) as *mut u32;
@@ -16,12 +17,34 @@ pub const RANDOM_NUMBER_POINTER  : *mut u32 = (BASE_POINTER + RANDOM_NUMBER_OFFS
 pub const BUTTONS_POINTER        : *mut u8  = (BASE_POINTER + BUTTONS_OFFSET)        as *mut u8;
 pub const TEXT_DISPLAY_POINTER   : *mut u8  = (BASE_POINTER + TEXT_DISPLAY_OFFSET)   as *mut u8;
 pub const KEYBOARD_POINTER       : *mut u32 = (BASE_POINTER + KEYBOARD_OFFSET)       as *mut u32;
+pub const SCREEN_CONTROL_POINTER : *mut u32 = (BASE_POINTER + SCREEN_CONTROL_OFFSET) as *mut u32;
 pub const SCREEN_POINTER         : *mut u32 = (BASE_POINTER + SCREEN_OFFSET)         as *mut u32;
 
+
+pub enum ScreenMode {
+    AlwaysDisplay,
+    Buffered,
+}
+
 pub struct Screen {}
 impl Screen {
+    const SCREEN_CLEAR: u32 = 0x0000_0001;
+    const SCREEN_DISPLAY: u32 = 0x0000_0100;
+
     #[inline]
-    pub fn clear() {}
+    pub fn init(mode: ScreenMode) {
+        unsafe {
+            write_volatile(SCREEN_CONTROL_POINTER, Self::SCREEN_CLEAR | Self::SCREEN_DISPLAY);
+            match mode {
+                ScreenMode::AlwaysDisplay => {
+                    write_volatile(SCREEN_CONTROL_POINTER, Self::SCREEN_DISPLAY);
+                },
+                ScreenMode::Buffered => {
+                    write_volatile(SCREEN_CONTROL_POINTER, 0);
+                }
+            }
+        }
+    }
     #[inline]
     pub fn turn_pixel_on(x: u8, y: u8) {
         unsafe {

test/src/main.rs

@@ -2,7 +2,7 @@
 #![no_main]
 
 use core::{fmt::Write, panic::PanicInfo, ptr::{read_volatile, write_volatile}};
-use lwcpu::{NumberDisplay, TextDisplay, SCREEN_POINTER};
+use lwcpu::{NumberDisplay, Screen, ScreenMode, TextDisplay, SCREEN_POINTER};
 use riscv_rt::entry;
 
 #[panic_handler]
@@ -17,6 +17,7 @@ const HELLO_WORLD: &str = " Hello world!";
 
 #[entry]
 fn main() -> ! {
+    Screen::init(ScreenMode::AlwaysDisplay);
     let mut text = TextDisplay{};
     unsafe {
         write_volatile(SCREEN_POINTER, 0x001166ff);