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// Example of polling TSC (Touch Sensing Controller) that lights an LED when touch is detected.
//
// Suggested physical setup on STM32F303ZE Nucleo board:
// - Connect a 1000pF capacitor between pin A0 and GND. This is your sampling capacitor.
// - Connect one end of a 1K resistor to pin A1 and leave the other end loose.
// The loose end will act as touch sensor which will register your touch.
//
// Troubleshooting the setup:
// - If no touch seems to be registered, then try to disconnect the sampling capacitor from GND momentarily,
// now the led should light up. Next try using a different value for the sampling capacitor.
// Also experiment with increasing the values for `ct_pulse_high_length`, `ct_pulse_low_length`, `pulse_generator_prescaler`, `max_count_value` and `discharge_delay`.
//
// All configuration values and sampling capacitor value have been determined experimentally.
// Suitable configuration and discharge delay values are highly dependent on the value of the sample capacitor. For example, a shorter discharge delay can be used with smaller capacitor values.
//
#![no_std]
#![no_main]
use defmt::*;
use embassy_stm32::gpio::{Level, Output, Speed};
use embassy_stm32::tsc::{self, *};
use embassy_time::Timer;
use {defmt_rtt as _, panic_probe as _};
/// This example is written for the nucleo-stm32f303ze, with a stm32f303ze chip.
///
/// Make sure you check/update the following (whether you use the F303ZE or another board):
///
/// * [ ] Update .cargo/config.toml with the correct `probe-rs run --chip STM32F303ZETx`chip name.
/// * [ ] Update Cargo.toml to have the correct `embassy-stm32` feature, for F303ZE it should be `stm32f303ze`.
/// * [ ] If your board has a special clock or power configuration, make sure that it is
/// set up appropriately.
/// * [ ] If your board has different pin mapping, update any pin numbers or peripherals
/// to match your schematic
///
/// If you are unsure, please drop by the Embassy Matrix chat for support, and let us know:
///
/// * Which example you are trying to run
/// * Which chip and board you are using
///
/// Embassy Chat: https://matrix.to/#/#embassy-rs:matrix.org
#[embassy_executor::main]
async fn main(_spawner: embassy_executor::Spawner) {
let device_config = embassy_stm32::Config::default();
let context = embassy_stm32::init(device_config);
let tsc_conf = Config {
ct_pulse_high_length: ChargeTransferPulseCycle::_8,
ct_pulse_low_length: ChargeTransferPulseCycle::_8,
spread_spectrum: false,
spread_spectrum_deviation: SSDeviation::new(2).unwrap(),
spread_spectrum_prescaler: false,
pulse_generator_prescaler: PGPrescalerDivider::_32,
max_count_value: MaxCount::_255,
io_default_mode: false,
synchro_pin_polarity: false,
acquisition_mode: false,
max_count_interrupt: false,
channel_ios: TscIOPin::Group1Io1.into(),
shield_ios: 0, // no shield
sampling_ios: TscIOPin::Group1Io2.into(),
};
let mut g1: PinGroup<embassy_stm32::peripherals::TSC, G1> = PinGroup::new();
g1.set_io1(context.PA0, PinType::Sample);
g1.set_io2(context.PA1, PinType::Channel);
let mut touch_controller = tsc::Tsc::new_blocking(context.TSC, Some(g1), None, None, None, None, None, tsc_conf);
// LED2 on the STM32F303ZE nucleo-board
let mut led = Output::new(context.PB7, Level::High, Speed::Low);
// smaller sample capacitor discharge faster and can be used with shorter delay.
let discharge_delay = 5; // ms
// the interval at which the loop polls for new touch sensor values
let polling_interval = 100; // ms
info!("polling for touch");
loop {
touch_controller.start();
touch_controller.poll_for_acquisition();
touch_controller.discharge_io(true);
Timer::after_millis(discharge_delay).await;
let grp1_status = touch_controller.group_get_status(Group::One);
match grp1_status {
GroupStatus::Complete => {
let group_one_val = touch_controller.group_get_value(Group::One);
info!("{}", group_one_val);
led.set_high();
}
GroupStatus::Ongoing => led.set_low(),
}
Timer::after_millis(polling_interval).await;
}
}
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