135 lines
4.7 KiB
Rust
135 lines
4.7 KiB
Rust
#![no_std]
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#![no_main]
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// Example originally designed for stm32f411ceu6 with three A1454 hall effect sensors, connected to I2C1, 2 and 3
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// on the pins referenced in the peripheral definitions.
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// Pins and DMA peripherals changed to compile for stm32f429zi, to work with the CI.
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// MUST be compiled in release mode to see actual performance, otherwise the async transactions take 2x
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// as long to complete as the blocking ones!
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use defmt::*;
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use embassy_executor::Spawner;
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use embassy_stm32::i2c::I2c;
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use embassy_stm32::time::Hertz;
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use embassy_stm32::{bind_interrupts, i2c, peripherals};
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use embassy_time::Instant;
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use futures::future::try_join3;
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use {defmt_rtt as _, panic_probe as _};
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const ADDRESS: u8 = 96;
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bind_interrupts!(struct Irqs {
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I2C1_EV => i2c::EventInterruptHandler<peripherals::I2C1>;
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I2C1_ER => i2c::ErrorInterruptHandler<peripherals::I2C1>;
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I2C2_EV => i2c::EventInterruptHandler<peripherals::I2C2>;
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I2C2_ER => i2c::ErrorInterruptHandler<peripherals::I2C2>;
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I2C3_EV => i2c::EventInterruptHandler<peripherals::I2C3>;
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I2C3_ER => i2c::ErrorInterruptHandler<peripherals::I2C3>;
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});
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/// Convert 12-bit signed integer within a 4 byte long buffer into 16-bit signed integer.
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fn a1454_buf_to_i16(buffer: &[u8; 4]) -> i16 {
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let lower = buffer[3];
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let mut upper = buffer[2];
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// Fill in additional 1s if the 12 bit number is negative.
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if (upper & 0b00001000) == 0b0001000 {
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upper = upper | 0b11110000;
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}
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let mut sensor_value_raw: u16 = lower.into();
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sensor_value_raw |= (upper as u16) << 8;
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let sensor_value: u16 = sensor_value_raw.into();
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let sensor_value = sensor_value as i16;
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sensor_value
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}
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#[embassy_executor::main]
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async fn main(_spawner: Spawner) {
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info!("Setting up peripherals.");
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let p = embassy_stm32::init(Default::default());
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let mut i2c1 = I2c::new(
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p.I2C1,
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p.PB8,
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p.PB7,
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Irqs,
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p.DMA1_CH6,
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p.DMA1_CH0,
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Hertz(100_000),
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Default::default(),
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);
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let mut i2c2 = I2c::new(
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p.I2C2,
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p.PB10,
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p.PB11,
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Irqs,
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p.DMA1_CH7,
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p.DMA1_CH3,
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Hertz(100_000),
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Default::default(),
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);
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let mut i2c3 = I2c::new(
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p.I2C3,
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p.PA8,
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p.PC9,
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Irqs,
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p.DMA1_CH4,
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p.DMA1_CH2,
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Hertz(100_000),
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Default::default(),
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);
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let a1454_read_sensor_command = [0x1F];
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let mut i2c1_buffer: [u8; 4] = [0, 0, 0, 0];
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let mut i2c2_buffer: [u8; 4] = [0, 0, 0, 0];
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let mut i2c3_buffer: [u8; 4] = [0, 0, 0, 0];
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loop {
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// Blocking reads one after the other. Completes in about 2000us.
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let blocking_read_start_us = Instant::now().as_micros();
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match i2c1.blocking_write_read(ADDRESS, &a1454_read_sensor_command, &mut i2c1_buffer) {
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Ok(()) => {}
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Err(e) => error!("I2C Error: {:?}", e),
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}
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match i2c2.blocking_write_read(ADDRESS, &a1454_read_sensor_command, &mut i2c2_buffer) {
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Ok(()) => {}
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Err(e) => error!("I2C Error: {:?}", e),
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}
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match i2c3.blocking_write_read(ADDRESS, &a1454_read_sensor_command, &mut i2c3_buffer) {
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Ok(()) => {}
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Err(e) => error!("I2C Error: {:?}", e),
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}
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let blocking_read_total_us = Instant::now().as_micros() - blocking_read_start_us;
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info!(
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"Blocking reads completed in {}us: i2c1: {} i2c2: {} i2c3: {}",
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blocking_read_total_us,
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a1454_buf_to_i16(&i2c1_buffer),
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a1454_buf_to_i16(&i2c2_buffer),
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a1454_buf_to_i16(&i2c3_buffer)
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);
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// Async reads overlapping. Completes in about 1000us.
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let async_read_start_us = Instant::now().as_micros();
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let i2c1_result = i2c1.write_read(ADDRESS, &a1454_read_sensor_command, &mut i2c1_buffer);
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let i2c2_result = i2c2.write_read(ADDRESS, &a1454_read_sensor_command, &mut i2c2_buffer);
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let i2c3_result = i2c3.write_read(ADDRESS, &a1454_read_sensor_command, &mut i2c3_buffer);
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// Wait for all three transactions to finish, or any one of them to fail.
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match try_join3(i2c1_result, i2c2_result, i2c3_result).await {
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Ok(_) => {
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let async_read_total_us = Instant::now().as_micros() - async_read_start_us;
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info!(
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"Async reads completed in {}us: i2c1: {} i2c2: {} i2c3: {}",
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async_read_total_us,
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a1454_buf_to_i16(&i2c1_buffer),
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a1454_buf_to_i16(&i2c2_buffer),
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a1454_buf_to_i16(&i2c3_buffer)
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);
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}
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Err(e) => error!("I2C Error during async write-read: {}", e),
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};
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}
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}
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