1ee4bb22de
Simple example exercising an mcp23017 GPIO expander, configured on RP2040 GPIOs 14+15 (i2c1) with 8 inputs and 8 outputs. Input bit 0 controls whether to display a mcp23017 register dump.
103 lines
2.6 KiB
Rust
103 lines
2.6 KiB
Rust
#![no_std]
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#![no_main]
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#![feature(type_alias_impl_trait)]
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use defmt::*;
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use embassy_executor::Spawner;
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use embassy_rp::i2c::{self, Config};
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use embassy_rp::interrupt;
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use embassy_time::{Duration, Timer};
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use embedded_hal_async::i2c::I2c;
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use {defmt_rtt as _, panic_probe as _};
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#[allow(dead_code)]
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mod mcp23017 {
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pub const ADDR: u8 = 0x20; // default addr
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macro_rules! mcpregs {
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($($name:ident : $val:expr),* $(,)?) => {
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$(
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pub const $name: u8 = $val;
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)*
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pub fn regname(reg: u8) -> &'static str {
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match reg {
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$(
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$val => stringify!($name),
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)*
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_ => panic!("bad reg"),
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}
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}
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}
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}
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// These are correct for IOCON.BANK=0
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mcpregs! {
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IODIRA: 0x00,
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IPOLA: 0x02,
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GPINTENA: 0x04,
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DEFVALA: 0x06,
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INTCONA: 0x08,
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IOCONA: 0x0A,
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GPPUA: 0x0C,
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INTFA: 0x0E,
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INTCAPA: 0x10,
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GPIOA: 0x12,
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OLATA: 0x14,
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IODIRB: 0x01,
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IPOLB: 0x03,
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GPINTENB: 0x05,
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DEFVALB: 0x07,
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INTCONB: 0x09,
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IOCONB: 0x0B,
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GPPUB: 0x0D,
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INTFB: 0x0F,
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INTCAPB: 0x11,
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GPIOB: 0x13,
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OLATB: 0x15,
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}
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}
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#[embassy_executor::main]
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async fn main(_spawner: Spawner) {
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let p = embassy_rp::init(Default::default());
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let sda = p.PIN_14;
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let scl = p.PIN_15;
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let irq = interrupt::take!(I2C1_IRQ);
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info!("set up i2c ");
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let mut i2c = i2c::I2c::new_async(p.I2C1, scl, sda, irq, Config::default());
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use mcp23017::*;
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info!("init mcp23017 config for IxpandO");
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// init - a outputs, b inputs
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i2c.write(ADDR, &[IODIRA, 0x00]).await.unwrap();
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i2c.write(ADDR, &[IODIRB, 0xff]).await.unwrap();
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i2c.write(ADDR, &[GPPUB, 0xff]).await.unwrap(); // pullups
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let mut val = 1;
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loop {
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let mut portb = [0];
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i2c.write_read(mcp23017::ADDR, &[GPIOB], &mut portb).await.unwrap();
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info!("portb = {:02x}", portb[0]);
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i2c.write(mcp23017::ADDR, &[GPIOA, val | portb[0]]).await.unwrap();
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val = val.rotate_left(1);
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// get a register dump
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info!("getting register dump");
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let mut regs = [0; 22];
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i2c.write_read(ADDR, &[0], &mut regs).await.unwrap();
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// always get the regdump but only display it if portb'0 is set
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if portb[0] & 1 != 0 {
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for (idx, reg) in regs.into_iter().enumerate() {
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info!("{} => {:02x}", regname(idx as u8), reg);
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}
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}
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Timer::after(Duration::from_millis(100)).await;
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}
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}
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