mirror of
https://github.com/italicsjenga/rp-hal-boards.git
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139 lines
4.5 KiB
Rust
139 lines
4.5 KiB
Rust
//! # LCD Display Example
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//!
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//! In this example, the RP2040 is configured to drive a small two-line
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//! alphanumeric LCD using the
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//! [HD44780](https://crates.io/crates/hd44780-driver) driver.
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//!
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//! This example drives the LCD by pushing data out of six GPIO pins, writing
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//! the data four bits at a time. A faster alternative can be created using
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//! HD44780::new_8bit() but requiring an additional four GPIO pins.
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//!
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//! See the `Cargo.toml` file for Copyright and license details.
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//!
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//! ```text
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//! /--------------------------------------\
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//! ____________ | /-------------------------\ |
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//! | 1 GND|-------+---\ | _|USB|_ | |
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//! | 2 VDD|-------+---+----/ |1 R 40|-VBUS-o v
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//! | 3 VS|-------/ | |2 P 39| ||POT||
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//! | 4 RS|--\ o-----------GND-|3 38|-GND----------o
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//! | 5 RW|--+--------/ /------GP2-|4 P 37|
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//! | 6 EN|--+-\ /--+------GP3-|5 I 36|
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//! | 7 | | | /--+--+------GP4-|6 C |
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//! | 8 | | | /--+--+--+------GP5-|7 O |
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//! | 9 | | \--+--+--+--+---\ |8 |
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//! | 10 | \----+--+--+--+-\ \-GP6-|9 |
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//! | 11 D4|-------/ | | | \---GP7-|10 |
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//! | 12 D5|----------/ | | .........
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//! | 13 D6|-------------/ | |20 21|
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//! | 14 D7|----------------/ """""""
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//! ..............
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//! Symbols:
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//! - (+) crossing lines, not connected
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//! - (o) connected lines
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//! ```
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//!
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//! See the `Cargo.toml` file for Copyright and license details.
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#![no_std]
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#![no_main]
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// The macro for our start-up function
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use cortex_m_rt::entry;
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// Ensure we halt the program on panic (if we don't mention this crate it won't
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// be linked)
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use panic_halt as _;
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// Pull in any important traits
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use rp_pico::hal::prelude::*;
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// GPIO traits
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use embedded_hal::digital::v2::OutputPin;
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// Time handling traits
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use embedded_time::rate::*;
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// For LCD display
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use hd44780_driver::HD44780;
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#[entry]
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fn main() -> ! {
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// Grab our singleton objects
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let mut pac = rp_pico::hal::pac::Peripherals::take().unwrap();
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let core = rp_pico::hal::pac::CorePeripherals::take().unwrap();
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// Set up the watchdog driver - needed by the clock setup code
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let mut watchdog = rp_pico::hal::Watchdog::new(pac.WATCHDOG);
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// Configure the clocks
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// The default is to generate a 125 MHz system clock
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let clocks = rp_pico::hal::clocks::init_clocks_and_plls(
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rp_pico::XOSC_CRYSTAL_FREQ,
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pac.XOSC,
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pac.CLOCKS,
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pac.PLL_SYS,
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pac.PLL_USB,
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&mut pac.RESETS,
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&mut watchdog,
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)
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.ok()
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.unwrap();
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// The single-cycle I/O block controls our GPIO pins
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let sio = rp_pico::hal::Sio::new(pac.SIO);
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// Set the pins up according to their function on this particular board
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let pins = rp_pico::Pins::new(
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pac.IO_BANK0,
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pac.PADS_BANK0,
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sio.gpio_bank0,
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&mut pac.RESETS,
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);
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let mut led_pin = pins.led.into_push_pull_output();
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// The delay object lets us wait for specified amounts of time
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let mut delay = cortex_m::delay::Delay::new(core.SYST, clocks.system_clock.freq().integer());
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// Init pins
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let rs = pins.gpio7.into_push_pull_output();
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let en = pins.gpio6.into_push_pull_output();
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let d4 = pins.gpio5.into_push_pull_output();
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let d5 = pins.gpio4.into_push_pull_output();
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let d6 = pins.gpio3.into_push_pull_output();
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let d7 = pins.gpio2.into_push_pull_output();
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// LCD Init
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let mut lcd = HD44780::new_4bit(rs, en, d4, d5, d6, d7, &mut delay).unwrap();
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loop {
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// Clear the screen
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lcd.reset(&mut delay).unwrap();
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lcd.clear(&mut delay).unwrap();
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// Write to the top line
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lcd.write_str("rp-hal on", &mut delay).unwrap();
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// Move the cursor
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lcd.set_cursor_pos(40, &mut delay).unwrap();
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// Write more more text
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lcd.write_str("HD44780! ", &mut delay).unwrap();
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let mut char_count = 9;
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for ch in "move along!.. ".chars() {
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if char_count > 15 {
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// Switch autoscroll on
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lcd.set_autoscroll(true, &mut delay).unwrap();
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}
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led_pin.set_high().unwrap();
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lcd.write_char(ch, &mut delay).unwrap();
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char_count += 1;
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delay.delay_us(400_000); //0.4s
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led_pin.set_low().unwrap();
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delay.delay_us(100_000); //0.1s
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}
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lcd.set_autoscroll(false, &mut delay).unwrap();
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}
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}
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