From 9f77dbf5ae442c1cac0c652b4ef25bf1c82ed9d4 Mon Sep 17 00:00:00 2001
From: Jeremy Fitzhardinge <jeremy@goop.org>
Date: Thu, 29 Sep 2022 02:01:58 -0700
Subject: [PATCH] rp i2c: blocking example

i2c example talking to mcp23017 i2c gpio expander.
---
 examples/rp/src/bin/i2c.rs | 70 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 examples/rp/src/bin/i2c.rs

diff --git a/examples/rp/src/bin/i2c.rs b/examples/rp/src/bin/i2c.rs
new file mode 100644
index 00000000..a5991d0d
--- /dev/null
+++ b/examples/rp/src/bin/i2c.rs
@@ -0,0 +1,70 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_rp::i2c::{self, Config};
+use embassy_time::{Duration, Timer};
+use embedded_hal_1::i2c::blocking::I2c;
+use {defmt_rtt as _, panic_probe as _};
+
+#[allow(dead_code)]
+mod mcp23017 {
+    pub const ADDR: u8 = 0x20; // default addr
+
+    pub const IODIRA: u8 = 0x00;
+    pub const IPOLA: u8 = 0x02;
+    pub const GPINTENA: u8 = 0x04;
+    pub const DEFVALA: u8 = 0x06;
+    pub const INTCONA: u8 = 0x08;
+    pub const IOCONA: u8 = 0x0A;
+    pub const GPPUA: u8 = 0x0C;
+    pub const INTFA: u8 = 0x0E;
+    pub const INTCAPA: u8 = 0x10;
+    pub const GPIOA: u8 = 0x12;
+    pub const OLATA: u8 = 0x14;
+    pub const IODIRB: u8 = 0x01;
+    pub const IPOLB: u8 = 0x03;
+    pub const GPINTENB: u8 = 0x05;
+    pub const DEFVALB: u8 = 0x07;
+    pub const INTCONB: u8 = 0x09;
+    pub const IOCONB: u8 = 0x0B;
+    pub const GPPUB: u8 = 0x0D;
+    pub const INTFB: u8 = 0x0F;
+    pub const INTCAPB: u8 = 0x11;
+    pub const GPIOB: u8 = 0x13;
+    pub const OLATB: u8 = 0x15;
+}
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let p = embassy_rp::init(Default::default());
+
+    let sda = p.PIN_14;
+    let scl = p.PIN_15;
+
+    info!("set up i2c ");
+    let mut i2c = i2c::I2c::new_blocking(p.I2C1, scl, sda, Config::default());
+
+    use mcp23017::*;
+
+    info!("init mcp23017 config for IxpandO");
+    // init - a outputs, b inputs
+    i2c.write(ADDR, &[IODIRA, 0x00]).unwrap();
+    i2c.write(ADDR, &[IODIRB, 0xff]).unwrap();
+    i2c.write(ADDR, &[GPPUB, 0xff]).unwrap(); // pullups
+
+    let mut val = 0xaa;
+    loop {
+        let mut portb = [0];
+
+        i2c.write(mcp23017::ADDR, &[GPIOA, val]).unwrap();
+        i2c.write_read(mcp23017::ADDR, &[GPIOB], &mut portb).unwrap();
+
+        info!("portb = {:02x}", portb[0]);
+        val = !val;
+
+        Timer::after(Duration::from_secs(1)).await;
+    }
+}