feat: lcd-clock

Cargo.toml

@@ -18,6 +18,9 @@ defmt = {version="1.0.1", optional= true}
 defmt-rtt = {version="1.0.0", optional=true}
 panic-probe = { version = "0.3", features = ["print-defmt"], optional=true }
 
+[profile.release]
+debug = "full" # those are not on the board
+
 [features]
 logging = ["dep:defmt", "dep:defmt-rtt", "dep:panic-probe"]
 
@@ -40,3 +43,13 @@ required-features = ["logging"]
 name = "aes_ecb"
 path = "examples/aes_ecb.rs"
 required-features = ["logging"]
+
+[[example]]
+name = "lcd"
+path = "examples/lcd.rs"
+required-features = ["logging"]
+
+[[example]]
+name = "lcd-clock"
+path = "examples/lcd-clock.rs"
+required-features = ["logging"]

examples/lcd-clock.rs

@@ -0,0 +1,131 @@
+#![no_main]
+#![no_std]
+
+use heapless::String;
+use panic_probe as _;
+
+use defmt_rtt as _; // global logger
+
+use core::fmt::Write;
+
+use cortex_m_rt::entry;
+use hal::{
+    delay::Delay,
+    gpio::{Output, PushPull, gpioa::*, gpiob::*, gpioc::*},
+    pac,
+    prelude::*,
+    pwr::PWR,
+    rcc::Config,
+    rtc::{Datelike, Rtc, Timelike},
+};
+use hd44780_driver::HD44780;
+
+#[defmt::panic_handler]
+fn panic() -> ! {
+    cortex_m::asm::udf()
+}
+
+type Lcd = HD44780<
+    hd44780_driver::bus::FourBitBus<
+        PA9<Output<PushPull>>,
+        PC7<Output<PushPull>>,
+        PB5<Output<PushPull>>,
+        PB4<Output<PushPull>>,
+        PB10<Output<PushPull>>,
+        PA8<Output<PushPull>>,
+    >,
+>;
+
+#[entry]
+fn main() -> ! {
+    let dp = pac::Peripherals::take().unwrap();
+    let cp = cortex_m::Peripherals::take().unwrap();
+
+    let mut rcc = dp.RCC.freeze(Config::hsi16());
+    let pwr = PWR::new(dp.PWR, &mut rcc);
+
+    let gpioa = dp.GPIOA.split(&mut rcc);
+    let gpiob = dp.GPIOB.split(&mut rcc);
+    let gpioc = dp.GPIOC.split(&mut rcc);
+
+    // literal D4-D7 ports etc as written on the nucleo board, mapped to the D4-D7 ports of the LCD
+    // controller
+    let d4 = gpiob.pb5.into_push_pull_output();
+    let d5 = gpiob.pb4.into_push_pull_output();
+    let d6 = gpiob.pb10.into_push_pull_output();
+    let d7 = gpioa.pa8.into_push_pull_output();
+
+    // clock enable on D9
+    let en = gpioc.pc7.into_push_pull_output();
+    // register select on D8, the lib wants that but I'd just put it on ground otherwise
+    let rs = gpioa.pa9.into_push_pull_output();
+
+    // See https://en.wikipedia.org/wiki/Hitachi_HD44780_LCD_controller#Interface
+    // for the pins of the LCD
+
+    let mut delay = cp.SYST.delay(rcc.clocks);
+
+    let mut rtc = Rtc::new(dp.RTC, &mut rcc, &pwr, None).unwrap();
+    let mut led = gpioa.pa5.into_push_pull_output();
+
+    let mut lcd: Lcd = HD44780::new_4bit(rs, en, d4, d5, d6, d7, &mut delay)
+        .expect("could not init HD44780 driver");
+    lcd.set_display_mode(
+        hd44780_driver::DisplayMode {
+            cursor_visibility: hd44780_driver::Cursor::Invisible,
+            cursor_blink: hd44780_driver::CursorBlink::Off,
+            display: hd44780_driver::Display::On,
+        },
+        &mut delay,
+    )
+    .expect("could not set display properties");
+    lcd.reset(&mut delay).expect("could not reset the lcd");
+    lcd.write_str("Hello world!", &mut delay)
+        .expect("could not write to LCD");
+
+    let mut buf: String<20> = String::new();
+    loop {
+        led.set_high().unwrap();
+
+        display_time(&mut rtc, &mut lcd, &mut delay, &mut buf);
+
+        led.set_low().unwrap();
+
+        delay.delay_ms(1000_u16);
+    }
+}
+
+fn display_time(rtc: &mut Rtc, lcd: &mut Lcd, delay: &mut Delay, buf: &mut String<20>) {
+    let timestamp = rtc.now();
+
+    lcd.clear(delay).expect("could not clear the display");
+
+    lcd.set_cursor_pos(0, delay)
+        .expect("could not move cursor to start");
+
+    buf.clear();
+    write!(
+        buf,
+        "      {:02}:{:02}:{:02}      ",
+        timestamp.hour(),
+        timestamp.minute(),
+        timestamp.second()
+    )
+    .expect("could not format text content for display");
+    lcd.write_str(buf, delay).expect("could not write to LCD");
+
+    lcd.set_cursor_pos(20, delay)
+        .expect("could not move cursor to line 2");
+
+    buf.clear();
+    write!(
+        buf,
+        "     {:04}-{:02}-{:02}     ",
+        timestamp.year(),
+        timestamp.month(),
+        timestamp.day()
+    )
+    .expect("could not format text content for display");
+
+    lcd.write_str(buf, delay).expect("could not write to LCD");
+}

examples/lcd.rs

@@ -72,14 +72,14 @@ fn main() -> ! {
 
         lcd.set_cursor_pos(0, &mut delay)
             .expect("could not move cursor to start");
-        lcd.write_str("Hello world!", &mut delay)
+        lcd.write_str("    Hello world!    ", &mut delay)
             .expect("could not write to LCD");
 
         lcd.set_cursor_pos(20, &mut delay)
             .expect("could not move cursor to line 2");
 
         buf.clear();
-        write!(&mut buf, "Iteration: {i}").expect("could not format text content for display");
+        write!(&mut buf, " Iteration: {i:07} ").expect("could not format text content for display");
 
         lcd.write_str(&buf, &mut delay)
             .expect("could not write to LCD");