From 10a1a27cc3ee9d2b445e86882d89633ec3de5f57 Mon Sep 17 00:00:00 2001
From: michel <michel@randahl.net>
Date: Wed, 10 Jul 2024 14:08:52 +0200
Subject: [PATCH] add async TSC example for STM32L073

---
 examples/stm32l0/src/bin/async-tsc.rs | 122 ++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 examples/stm32l0/src/bin/async-tsc.rs

diff --git a/examples/stm32l0/src/bin/async-tsc.rs b/examples/stm32l0/src/bin/async-tsc.rs
new file mode 100644
index 000000000..c40b86af9
--- /dev/null
+++ b/examples/stm32l0/src/bin/async-tsc.rs
@@ -0,0 +1,122 @@
+// Example of async TSC (Touch Sensing Controller) that lights an LED when touch is detected.
+//
+// Suggested physical setup on STM32L073RZ 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::bind_interrupts;
+use embassy_stm32::gpio::{Level, Output, Speed};
+use embassy_stm32::tsc::{self, *};
+use embassy_time::Timer;
+use {defmt_rtt as _, panic_probe as _};
+
+bind_interrupts!(struct Irqs {
+    TSC => InterruptHandler<embassy_stm32::peripherals::TSC>;
+});
+
+#[cortex_m_rt::exception]
+unsafe fn HardFault(_: &cortex_m_rt::ExceptionFrame) -> ! {
+    cortex_m::peripheral::SCB::sys_reset();
+}
+
+/// This example is written for the nucleo-stm32l073rz, with a stm32l073rz chip.
+///
+/// Make sure you check/update the following (whether you use the L073RZ or another board):
+///
+/// * [ ] Update .cargo/config.toml with the correct `probe-rs run --chip STM32L073RZTx`chip name.
+/// * [ ] Update Cargo.toml to have the correct `embassy-stm32` feature, for L073RZ it should be `stm32l073rz`.
+/// * [ ] 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 config = tsc::Config {
+        ct_pulse_high_length: ChargeTransferPulseCycle::_4,
+        ct_pulse_low_length: ChargeTransferPulseCycle::_4,
+        spread_spectrum: false,
+        spread_spectrum_deviation: SSDeviation::new(2).unwrap(),
+        spread_spectrum_prescaler: false,
+        pulse_generator_prescaler: PGPrescalerDivider::_16,
+        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_async(
+        context.TSC,
+        Some(g1),
+        None,
+        None,
+        None,
+        None,
+        None,
+        None,
+        None,
+        config,
+        Irqs,
+    );
+
+    // Check if TSC is ready
+    if touch_controller.get_state() != State::Ready {
+        info!("TSC not ready!");
+        loop {} // Halt execution
+    }
+    info!("TSC initialized successfully");
+
+    // LED2 on the STM32L073RZ nucleo-board (PA5)
+    let mut led = Output::new(context.PA5, Level::High, Speed::Low);
+
+    // smaller sample capacitor discharge faster and can be used with shorter delay.
+    let discharge_delay = 5; // ms
+
+    info!("Starting touch_controller interface");
+    loop {
+        touch_controller.start();
+        touch_controller.pend_for_acquisition().await;
+        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(),
+        }
+    }
+}