Adding initial support for configuring parameters via USB

Cargo.toml

@@ -34,6 +34,8 @@ default-target = "thumbv7em-none-eabihf"
 members = ["ad9959"]
 
 [dependencies]
+embedded-storage = "0.3"
+menu = "0.3"
 cortex-m = { version = "0.7.7", features = ["inline-asm", "critical-section-single-core"] }
 cortex-m-rt = { version = "0.7", features = ["device"] }
 log = { version = "0.4", features = ["max_level_trace", "release_max_level_info"] }
@@ -67,6 +69,7 @@ usbd-serial = "0.1.1"
 miniconf = "0.9.0"
 smoltcp-nal = { version = "0.4.1", features = ["shared-stack"]}
 bbqueue = "0.5"
+postcard = "1"
 
 [dependencies.stm32h7xx-hal]
 version = "0.15.1"

book/src/setup.md

@@ -40,10 +40,8 @@ Stabilizer requires an MQTT broker that supports MQTTv5.
 The MQTT broker is used to distribute and exchange elemetry data and to view/change application settings.
 The broker must be reachable by both the host-side applications used to
 interact with the application on Stabilizer and by the application running on Stabilizer.
-Determine the IPv4 address of the broker as seen from the network Stabilizer is
-connected to. The broker IP address must be stable. It will be used later
-during firmware build.
-The broker must be reachable on port 1883 on that IP address.
+The broker must be reachable on port 1883 on that IP address - it may either be an IP address or a
+fully qualified domain name.
 Firewalls between Stabilizer and the broker may need to be configured to
 allow connections from Stabilizer to that port and IP address.
 
@@ -83,23 +81,21 @@ docker run -p 1883:1883 --name mosquitto -v ${pwd}/mosquitto.conf:/mosquitto/con
     git clone https://github.com/quartiq/stabilizer
     cd stabilizer
     ```
-5. Build firmware specifying the MQTT broker IP. Replace `10.34.16.1` by the
-    stable and reachable broker IPv4 address determined above.
+5. Build firmware
     ```bash
     # Bash
-    BROKER="10.34.16.1" cargo build --release
+    cargo build --release
 
     # Powershell
-    # Note: This sets the broker for all future builds as well.
-    $env:BROKER='10.34.16.1'; cargo build --release
+    cargo build --release
     ```
 6. Extract the application binary (substitute `dual-iir` below with the desired application name)
     ```bash
     # Bash
-    BROKER="10.34.16.1" cargo objcopy --release --bin dual-iir -- -O binary dual-iir.bin
+    cargo objcopy --release --bin dual-iir -- -O binary dual-iir.bin
 
     # Powershell
-    $env:BROKER='10.34.16.1'; cargo objcopy --release --bin dual-iir -- -O binary dual-iir.bin
+    cargo objcopy --release --bin dual-iir -- -O binary dual-iir.bin
     ```
 
 ## Flashing
@@ -163,16 +159,29 @@ described [above](#st-link-virtual-mass-storage).
 2. Build and run firmware on the device
     ```bash
     # Bash
-    BROKER="10.34.16.1" cargo run --release --bin dual-iir
+    cargo run --release --bin dual-iir
 
     # Powershell
-    $Env:BROKER='10.34.16.1'; cargo run --release --bin dual-iir
+    cargo run --release --bin dual-iir
     ```
 
 When using debug (non `--release`) mode, decrease the sampling frequency significantly.
 The added error checking code and missing optimizations may lead to the application
 missing timer deadlines and panicing.
 
+## Set the MQTT broker
+
+The MQTT broker can be configured via the USB port on Stabilizer's front. Connect a USB cable and
+open up the serial port in a serial terminal of your choice. `pyserial` provides a simple,
+easy-to-use terminal emulator:
+```sh
+python -m serial <port>
+```
+
+Once you have opened the port, you can use the provided menu to update the MQTT broker address. The
+address can be an IP address or a domain name. Once the broker has been updated, power cycle
+stabilizer to have the new broker address take effect.
+
 ## Verify MQTT connection
 
 Once your MQTT broker and Stabilizer are both running, verify that the application
@@ -190,7 +199,8 @@ Broker.
 
 ![MQTT Explorer Configuration](assets/mqtt-explorer.png)
 
-> **Note:** In MQTT explorer, use the same broker address that you used when building the firmware.
+> **Note:** In MQTT explorer, use the same broker address that you set in the Stabilizer serial
+> terminal.
 
 In addition to the `alive` status, telemetry messages are published at regular intervals
 when Stabilizer has connected to the broker. Once you observe incoming telemetry,

src/bin/dual-iir.rs

@@ -208,21 +208,22 @@ mod app {
         let clock = SystemTimer::new(|| monotonics::now().ticks() as u32);
 
         // Configure the microcontroller
-        let (stabilizer, _pounder) = hardware::setup::setup(
+        let (mut stabilizer, _pounder) = hardware::setup::setup(
             c.core,
             c.device,
             clock,
             BATCH_SIZE,
             SAMPLE_TICKS,
         );
 
+        let flash = stabilizer.usb_serial.flash();
         let mut network = NetworkUsers::new(
             stabilizer.net.stack,
             stabilizer.net.phy,
             clock,
             env!("CARGO_BIN_NAME"),
-            stabilizer.net.mac_address,
-            option_env!("BROKER").unwrap_or("mqtt"),
+            &flash.settings.broker,
+            &flash.settings.id,
         );
 
         let generator = network.configure_streaming(StreamFormat::AdcDacData);

src/bin/lockin.rs

@@ -256,13 +256,14 @@ mod app {
             SAMPLE_TICKS,
         );
 
+        let flash = stabilizer.usb_serial.flash();
         let mut network = NetworkUsers::new(
             stabilizer.net.stack,
             stabilizer.net.phy,
             clock,
             env!("CARGO_BIN_NAME"),
-            stabilizer.net.mac_address,
-            option_env!("BROKER").unwrap_or("mqtt"),
+            &flash.settings.broker,
+            &flash.settings.id,
         );
 
         let generator = network.configure_streaming(StreamFormat::AdcDacData);

src/hardware/flash.rs

@@ -0,0 +1,65 @@
+use core::fmt::Write;
+use embedded_storage::nor_flash::{NorFlash, ReadNorFlash};
+use stm32h7xx_hal::flash::{LockedFlashBank, UnlockedFlashBank};
+
+#[derive(Clone, serde::Serialize, serde::Deserialize, miniconf::Tree)]
+pub struct Settings {
+    pub broker: heapless::String<255>,
+    pub id: heapless::String<23>,
+    #[serde(skip)]
+    #[tree(skip)]
+    pub mac: smoltcp_nal::smoltcp::wire::EthernetAddress,
+}
+
+impl Settings {
+    fn new(mac: smoltcp_nal::smoltcp::wire::EthernetAddress) -> Self {
+        let mut id = heapless::String::new();
+        write!(&mut id, "{mac}").unwrap();
+
+        Self {
+            broker: "mqtt".into(),
+            id,
+            mac,
+        }
+    }
+
+    pub fn reset(&mut self) {
+        *self = Self::new(self.mac)
+    }
+}
+
+pub struct FlashSettings {
+    flash: LockedFlashBank,
+    pub settings: Settings,
+}
+
+impl FlashSettings {
+    pub fn new(
+        mut flash: LockedFlashBank,
+        mac: smoltcp_nal::smoltcp::wire::EthernetAddress,
+    ) -> Self {
+        let mut buffer = [0u8; 512];
+        flash.read(0, &mut buffer[..]).unwrap();
+
+        let settings = match postcard::from_bytes(&buffer) {
+            Ok(settings) => settings,
+            Err(_) => {
+                log::warn!(
+                    "Failed to load settings from flash. Using defaults"
+                );
+                Settings::new(mac)
+            }
+        };
+
+        Self { flash, settings }
+    }
+
+    pub fn save(&mut self) {
+        let mut bank = self.flash.unlocked();
+
+        let mut data = [0; 512];
+        let serialized = postcard::to_slice(&self.settings, &mut data).unwrap();
+        bank.erase(0, UnlockedFlashBank::ERASE_SIZE as u32).unwrap();
+        bank.write(0, serialized).unwrap();
+    }
+}

src/hardware/mod.rs

@@ -9,6 +9,7 @@ pub mod cpu_temp_sensor;
 pub mod dac;
 pub mod delay;
 pub mod design_parameters;
+pub mod flash;
 pub mod input_stamper;
 pub mod pounder;
 pub mod serial_terminal;