rp/examples: add spi example

examples/rp/src/bin/spi.rs

@@ -0,0 +1,50 @@
+#![no_std]
+#![no_main]
+#![feature(asm)]
+#![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::*;
+use embassy::executor::Spawner;
+use embassy_rp::gpio::NoPin;
+use embassy_rp::spi;
+use embassy_rp::spi::Spi;
+use embassy_rp::{gpio, Peripherals};
+use gpio::{Level, Output};
+
+#[embassy::main]
+async fn main(_spawner: Spawner, p: Peripherals) {
+    info!("Hello World!");
+
+    // Example for resistive touch sensor in Waveshare Pico-ResTouch
+
+    let miso = p.PIN_12;
+    let mosi = p.PIN_11;
+    let clk = p.PIN_10;
+    let touch_cs = p.PIN_16;
+
+    // create SPI
+    let mut config = spi::Config::default();
+    config.frequency = 2_000_000;
+    let mut spi = Spi::new(p.SPI1, clk, mosi, miso, NoPin, config);
+
+    // Configure CS
+    let mut cs = Output::new(touch_cs, Level::Low);
+
+    loop {
+        cs.set_low();
+        let mut buf = [0x90, 0x00, 0x00, 0xd0, 0x00, 0x00];
+        spi.transfer(&mut buf);
+        cs.set_high();
+
+        let x = (buf[1] as u32) << 5 | (buf[2] as u32) >> 3;
+        let y = (buf[4] as u32) << 5 | (buf[5] as u32) >> 3;
+
+        info!("touch: {=u32} {=u32}", x, y);
+    }
+}