nrf/twim: add examples

embassy-nrf-examples/src/bin/twim.rs

@@ -0,0 +1,35 @@
+//! Example on how to read a 24C/24LC i2c eeprom.
+//!
+//! Connect SDA to P0.03, SCL to P0.04
+
+#![no_std]
+#![no_main]
+#![feature(min_type_alias_impl_trait)]
+#![feature(impl_trait_in_bindings)]
+#![feature(type_alias_impl_trait)]
+#![allow(incomplete_features)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+
+use defmt::{panic, *};
+use embassy::executor::Spawner;
+use embassy_nrf::twim::{self, Twim};
+use embassy_nrf::{interrupt, Peripherals};
+
+const ADDRESS: u8 = 0x50;
+
+#[embassy::main]
+async fn main(_spawner: Spawner, p: Peripherals) {
+    info!("Initializing TWI...");
+    let config = twim::Config::default();
+    let irq = interrupt::take!(SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0);
+    let mut twi = Twim::new(p.TWISPI0, irq, p.P0_03, p.P0_04, config);
+
+    info!("Reading...");
+
+    let mut buf = [0u8; 16];
+    twi.write_then_read(ADDRESS, &mut [0x00], &mut buf).unwrap();
+
+    info!("Read: {=[u8]:x}", buf);
+}

embassy-nrf-examples/src/bin/twim_lowpower.rs

@@ -0,0 +1,54 @@
+//! Example on how to read a 24C/24LC i2c eeprom with low power consumption.
+//! The eeprom is read every 1 second, while ensuring lowest possible power while
+//! sleeping between reads.
+//!
+//! Connect SDA to P0.03, SCL to P0.04
+
+#![no_std]
+#![no_main]
+#![feature(min_type_alias_impl_trait)]
+#![feature(impl_trait_in_bindings)]
+#![feature(type_alias_impl_trait)]
+#![allow(incomplete_features)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+
+use core::mem;
+
+use defmt::{panic, *};
+use embassy::executor::Spawner;
+use embassy::time::{Duration, Timer};
+use embassy_nrf::twim::{self, Twim};
+use embassy_nrf::{interrupt, Peripherals};
+
+const ADDRESS: u8 = 0x50;
+
+#[embassy::main]
+async fn main(_spawner: Spawner, mut p: Peripherals) {
+    info!("Started!");
+    let mut irq = interrupt::take!(SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0);
+
+    loop {
+        info!("Initializing TWI...");
+        let config = twim::Config::default();
+
+        // Create the TWIM instance with borrowed singletons, so they're not consumed.
+        let mut twi = Twim::new(&mut p.TWISPI0, &mut irq, &mut p.P0_03, &mut p.P0_04, config);
+
+        info!("Reading...");
+
+        let mut buf = [0u8; 16];
+        twi.write_then_read(ADDRESS, &mut [0x00], &mut buf).unwrap();
+
+        info!("Read: {=[u8]:x}", buf);
+
+        // Drop the TWIM instance. This disables the peripehral and deconfigures the pins.
+        // This clears the borrow on the singletons, so they can now be used again.
+        mem::drop(twi);
+
+        // Sleep for 1 second. The executor ensures the core sleeps with a WFE when it has nothing to do.
+        // During this sleep, the nRF chip should only use ~3uA
+        Timer::after(Duration::from_secs(1)).await;
+    }
+}