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