WIP: get Heltec V3 working

clients/python/donglora/__init__.py

@@ -19,9 +19,17 @@ from cobs import cobs
 
 USB_VID_PID = "1209:5741"
 
+# Known USB-UART bridge VID:PIDs found on some board revisions.
+BRIDGE_VID_PIDS = {"10c4:ea60", "1a86:55d4", "1a86:7523", "0403:6001"}
+
 
 def find_port() -> str | None:
-    """Find the DongLoRa serial port by USB VID:PID."""
+    """Find the DongLoRa serial port by USB VID:PID.
+
+    Checks for native USB CDC-ACM first (1209:5741), then falls back to
+    known USB-UART bridge chips found on some board revisions.
+    """
+    bridge_match = None
     for path in sorted(glob.glob("/dev/ttyACM*")) + sorted(glob.glob("/dev/ttyUSB*")):
         try:
             result = subprocess.run(
@@ -33,11 +41,16 @@ def find_port() -> str | None:
             )
             vid = props.get("ID_VENDOR_ID", "").lower()
             pid = props.get("ID_MODEL_ID", "").lower()
-            if f"{vid}:{pid}" == USB_VID_PID:
+            vid_pid = f"{vid}:{pid}"
+            if vid_pid == USB_VID_PID:
                 return path
+            if bridge_match is None and vid_pid in BRIDGE_VID_PIDS:
+                bridge_match = path
         except Exception:
             continue
-    ports = sorted(glob.glob("/dev/ttyACM*"))
+    if bridge_match is not None:
+        return bridge_match
+    ports = sorted(glob.glob("/dev/ttyACM*")) + sorted(glob.glob("/dev/ttyUSB*"))
     return ports[0] if ports else None
 
 
@@ -345,7 +358,7 @@ def connect(port: str | None = None, timeout: float = 2.0) -> serial.Serial | Mu
         # No mux available — direct USB serial
     if port is None:
         port = wait_for_device()
-    ser = serial.Serial(port, timeout=timeout)
+    ser = serial.Serial(port, baudrate=115200, timeout=timeout)
     ser.reset_input_buffer()
     return ser
 

clients/rust/src/discovery.rs

@@ -13,18 +13,41 @@ pub const USB_VID: u16 = 0x1209;
 /// DongLoRa USB Product ID.
 pub const USB_PID: u16 = 0x5741;
 
+/// Known USB-UART bridge VID:PIDs found on some board revisions.
+const BRIDGE_VID_PIDS: &[(u16, u16)] = &[
+    (0x10C4, 0xEA60), // CP2102 (Silicon Labs)
+    (0x1A86, 0x55D4), // CH9102
+    (0x1A86, 0x7523), // CH340
+    (0x0403, 0x6001), // FT232R (FTDI)
+];
+
 /// Find the DongLoRa serial port by USB VID:PID.
 ///
+/// Checks for native USB CDC-ACM first (VID:PID 1209:5741), then falls
+/// back to known USB-UART bridge chips found on some board revisions.
 /// Returns the first matching port path, or `None` if no device is found.
 pub fn find_port() -> Option<String> {
     let ports = serialport::available_ports().ok()?;
+
+    // Prefer native USB (our custom VID:PID)
+    if let Some(port) = ports.iter().find(|p| {
+        matches!(
+            &p.port_type,
+            serialport::SerialPortType::UsbPort(info)
+                if info.vid == USB_VID && info.pid == USB_PID
+        )
+    }) {
+        return Some(port.port_name.clone());
+    }
+
+    // Fall back to known USB-UART bridge chips
     ports
         .into_iter()
         .find(|p| {
             matches!(
                 &p.port_type,
                 serialport::SerialPortType::UsbPort(info)
-                    if info.vid == USB_VID && info.pid == USB_PID
+                    if BRIDGE_VID_PIDS.contains(&(info.vid, info.pid))
             )
         })
         .map(|p| p.port_name)

firmware/TODO.md

@@ -0,0 +1,7 @@
+- firmware file naming, no "release", add version
+- LED blinking on TX/RX? colored?
+- display having board specific stuff in it
+- publish new client, mux, bridge (updates in client for UART crap)
+- try to get heltec v3 back to the right USB port+VID:PID
+- split out mux and client repos
+- move to GH organization

firmware/justfile

@@ -73,7 +73,7 @@ flash board:
     @read -r feat target chip <<< "$(just _info {{board}})"; \
     case "$target" in \
         xtensa-*) \
-            port=$(just _find_port "303a:1001" "1209:5741"); \
+            port=$(just _find_port "303a:1001" "1209:5741" "10c4:ea60"); \
             if [ -n "$port" ]; then \
                 echo "Using $port"; \
                 espflash flash -p "$port" "{{builds_dir}}/donglora-{{board}}-release.elf"; \

firmware/src/board/esp32s3.rs

@@ -28,8 +28,12 @@ type Iv = GenericSx126xInterfaceVariant<Output<'static>, Input<'static>>;
 type RadioSpiDevice = SpiDevice<'static, NoopRawMutex, SpiBus, Nss>;
 pub type RadioDriver = Sx126x<RadioSpiDevice, Iv, Sx1262>;
 
+#[cfg(not(feature = "heltec_v3"))]
 pub type UsbDriver = esp_hal::otg_fs::asynch::Driver<'static>;
 
+#[cfg(feature = "heltec_v3")]
+pub type UartDriver = esp_hal::uart::Uart<'static, esp_hal::Async>;
+
 pub type DisplayI2c = I2c<'static, esp_hal::Async>;
 
 // ── Peripheral bundles ───────────────────────────────────────────────
@@ -39,10 +43,16 @@ pub struct RadioParts {
     pub delay: Delay,
 }
 
+#[cfg(not(feature = "heltec_v3"))]
 pub struct UsbParts {
     pub driver: UsbDriver,
 }
 
+#[cfg(feature = "heltec_v3")]
+pub struct UartParts {
+    pub driver: UartDriver,
+}
+
 pub struct DisplayParts {
     pub i2c: DisplayI2c,
     pub mac: [u8; 6],
@@ -107,7 +117,7 @@ pub fn init_radio(
 
     let sx_config = sx126x::Config {
         chip: Sx1262,
-        tcxo_ctrl: Some(sx126x::TcxoCtrlVoltage::Ctrl1V7),
+        tcxo_ctrl: Some(sx126x::TcxoCtrlVoltage::Ctrl1V8),
         use_dcdc: true,
         rx_boost: false,
     };
@@ -118,6 +128,7 @@ pub fn init_radio(
     }
 }
 
+#[cfg(not(feature = "heltec_v3"))]
 /// Initialize USB OTG CDC-ACM driver.
 pub fn init_usb(
     usb0: esp_hal::peripherals::USB0<'static>,
@@ -136,6 +147,24 @@ pub fn init_usb(
     }
 }
 
+#[cfg(feature = "heltec_v3")]
+/// Initialize UART0 for boards with USB-UART bridge chips (e.g. CP2102).
+pub fn init_uart(
+    uart0: esp_hal::peripherals::UART0<'static>,
+    tx: esp_hal::peripherals::GPIO43<'static>,
+    rx: esp_hal::peripherals::GPIO44<'static>,
+) -> UartParts {
+    use esp_hal::uart::{Config as UartConfig, Uart};
+
+    let uart = Uart::new(uart0, UartConfig::default())
+        .expect("UART init")
+        .with_tx(tx)
+        .with_rx(rx)
+        .into_async();
+
+    UartParts { driver: uart }
+}
+
 /// Initialize I2C bus for display.
 pub fn init_display_i2c(
     i2c0: esp_hal::peripherals::I2C0<'static>,

firmware/src/board/heltec_v3.rs

@@ -3,8 +3,8 @@ use esp_hal::gpio::{Level, Output, OutputConfig};
 use super::esp32s3;
 use super::traits::LoRaBoard;
 
-#[allow(unused_imports)] // Re-exported for other modules (display, radio, usb tasks)
-pub use super::esp32s3::{DisplayI2c, DisplayParts, RadioDriver, RadioParts, UsbDriver, UsbParts};
+#[allow(unused_imports)] // Re-exported for other modules (display, radio, uart tasks)
+pub use super::esp32s3::{DisplayI2c, DisplayParts, RadioDriver, RadioParts, UartDriver, UartParts};
 
 // ── Board init ───────────────────────────────────────────────────────
 
@@ -27,23 +27,31 @@ impl LoRaBoard for Board {
 }
 
 impl Board {
-    pub fn into_parts(self) -> (RadioParts, UsbParts, Option<DisplayParts>) {
+    pub fn into_parts(self) -> (RadioParts, UartParts, Option<DisplayParts>) {
         let p = self.p;
 
         esp32s3::start_timer(p.TIMG0);
 
-        // Vext power: GPIO21, active LOW to enable OLED
-        let vext = Output::new(p.GPIO21, Level::Low, OutputConfig::default());
+        // Vext power: GPIO36, active LOW to enable peripherals
+        let vext = Output::new(p.GPIO36, Level::Low, OutputConfig::default());
         core::mem::forget(vext); // hold pin low permanently; drop would reset it
 
         let radio = esp32s3::init_radio(
             p.SPI2, p.DMA_CH0, p.GPIO9, p.GPIO10, p.GPIO11, p.GPIO8, p.GPIO12, p.GPIO14, p.GPIO13,
         );
-        let usb = esp32s3::init_usb(p.USB0, p.GPIO20, p.GPIO19);
+        let uart = esp32s3::init_uart(p.UART0, p.GPIO43, p.GPIO44);
+
+        // SSD1306 display reset: pulse GPIO21 low->high before I2C init
+        let mut display_rst = Output::new(p.GPIO21, Level::Low, OutputConfig::default());
+        esp_hal::delay::Delay::new().delay_millis(10);
+        display_rst.set_high();
+        esp_hal::delay::Delay::new().delay_millis(10);
+        core::mem::forget(display_rst); // hold reset high permanently
+
         let i2c = esp32s3::init_display_i2c(p.I2C0, p.GPIO17, p.GPIO18);
         let mac = Self::mac_address();
         let display = Some(DisplayParts { i2c, mac });
 
-        (radio, usb, display)
+        (radio, uart, display)
     }
 }

firmware/src/board/rak_wisblock_4631.rs

@@ -112,7 +112,7 @@ impl Board {
 
         let sx_config = sx126x::Config {
             chip: Sx1262,
-            tcxo_ctrl: Some(sx126x::TcxoCtrlVoltage::Ctrl1V7),
+            tcxo_ctrl: Some(sx126x::TcxoCtrlVoltage::Ctrl1V8),
             use_dcdc: true,
             rx_boost: false,
         };

firmware/src/main.rs

@@ -3,11 +3,11 @@
 //! Three async tasks communicate via static channels:
 //!
 //! ```text
-//! usb_task ──Command──► radio_task ──► SX1262
-//!          ◄──Response──     │
-//!                       StatusWatch
-//!                            ▼
-//!                      display_task (optional)
+//! host_task ──Command──► radio_task ──► SX1262
+//!           ◄──Response──     │
+//!                        StatusWatch
+//!                             ▼
+//!                       display_task (optional)
 //! ```
 //!
 //! The host drives everything. The radio idles until commanded.
@@ -24,7 +24,11 @@ mod display;
 mod protocol;
 #[cfg(not(test))]
 mod radio;
-#[cfg(not(test))]
+#[cfg(all(not(test), feature = "heltec_v3"))]
+mod protocol_io;
+#[cfg(all(not(test), feature = "heltec_v3"))]
+mod uart;
+#[cfg(all(not(test), not(feature = "heltec_v3")))]
 mod usb;
 
 #[cfg(not(test))]
@@ -74,23 +78,39 @@ cfg_if::cfg_if! {
 async fn run(spawner: Spawner) {
     let board = <board::Board as LoRaBoard>::init();
     let mac = board::Board::mac_address();
-    let (radio, usb, display) = board.into_parts();
+    let (radio, comm, display) = board.into_parts();
 
     let has_display = display.is_some();
 
     spawner
         .spawn(radio::radio_task(radio, &COMMANDS, &RESPONSES, &STATUS))
         .expect("spawn radio_task");
-    spawner
-        .spawn(usb::usb_task(
-            usb,
-            &COMMANDS,
-            &RESPONSES,
-            &DISPLAY_COMMANDS,
-            has_display,
-            mac,
-        ))
-        .expect("spawn usb_task");
+
+    cfg_if::cfg_if! {
+        if #[cfg(feature = "heltec_v3")] {
+            spawner
+                .spawn(uart::uart_task(
+                    comm,
+                    &COMMANDS,
+                    &RESPONSES,
+                    &DISPLAY_COMMANDS,
+                    has_display,
+                    mac,
+                ))
+                .expect("spawn uart_task");
+        } else {
+            spawner
+                .spawn(usb::usb_task(
+                    comm,
+                    &COMMANDS,
+                    &RESPONSES,
+                    &DISPLAY_COMMANDS,
+                    has_display,
+                    mac,
+                ))
+                .expect("spawn usb_task");
+        }
+    }
 
     if let Some(dp) = display {
         spawner

firmware/src/protocol_io.rs

@@ -0,0 +1,124 @@
+//! Shared COBS protocol helpers for USB and UART transports.
+//!
+//! Both `usb_task` and `uart_task` use these helpers for frame
+//! accumulation, response encoding, and command routing.
+
+use defmt::warn;
+
+use crate::channel::{CommandChannel, DisplayCommand, DisplayCommandChannel, ResponseChannel};
+use crate::protocol::{Command, ErrorCode, Response};
+
+/// Maximum COBS frame size (bytes).
+pub const MAX_FRAME: usize = 512;
+
+// Worst case: tag(1) + rssi(2) + snr(2) + len(2) + payload(256) = 263 bytes.
+// COBS adds ceil(263/254)+1 = 3 bytes. 266 < 512. Plenty of room.
+const _: () = assert!(
+    MAX_FRAME >= crate::protocol::MAX_PAYLOAD + 64,
+    "MAX_FRAME too small for max payload + COBS overhead"
+);
+
+/// Accumulates bytes into complete COBS frames.
+pub struct FrameAccumulator {
+    buf: [u8; MAX_FRAME],
+    len: usize,
+}
+
+impl FrameAccumulator {
+    pub const fn new() -> Self {
+        Self {
+            buf: [0u8; MAX_FRAME],
+            len: 0,
+        }
+    }
+
+    /// Reset the accumulator (discard partial frame).
+    pub fn reset(&mut self) {
+        self.len = 0;
+    }
+
+    /// Feed a chunk of bytes, calling `on_command` for each decoded command.
+    pub fn feed(&mut self, data: &[u8], mut on_command: impl FnMut(Command)) {
+        for &byte in data {
+            if byte == 0x00 {
+                // End of COBS frame — decode and dispatch
+                if self.len > 0 {
+                    let mut decode_buf = [0u8; MAX_FRAME];
+                    if let Some(decoded_len) =
+                        ucobs::decode(&self.buf[..self.len], &mut decode_buf)
+                    {
+                        if let Some(cmd) = Command::from_bytes(&decode_buf[..decoded_len]) {
+                            on_command(cmd);
+                        }
+                    }
+                }
+                self.len = 0;
+            } else if self.len < MAX_FRAME {
+                self.buf[self.len] = byte;
+                self.len += 1;
+            } else {
+                // Frame too large — discard
+                self.len = 0;
+            }
+        }
+    }
+}
+
+/// COBS-encode a response into `encode_buf` with trailing 0x00 sentinel.
+///
+/// Returns the slice to send (encoded frame + sentinel), or `None` on overflow.
+pub fn encode_response<'a>(
+    response: Response,
+    write_buf: &mut [u8; MAX_FRAME],
+    encode_buf: &'a mut [u8; MAX_FRAME],
+) -> Option<&'a [u8]> {
+    let raw_len = response.write_to(write_buf);
+    let encoded_len = ucobs::encode(&write_buf[..raw_len], encode_buf).unwrap_or(0);
+    if encoded_len < encode_buf.len() {
+        encode_buf[encoded_len] = 0x00;
+        Some(&encode_buf[..encoded_len + 1])
+    } else {
+        warn!("COBS encode buffer overflow");
+        None
+    }
+}
+
+/// Route a parsed command to the appropriate handler.
+///
+/// Display and MAC commands are handled locally (response sent immediately).
+/// All other commands are forwarded to the radio task (response sent later).
+/// Both paths feed the same `ResponseChannel`, so the one-outstanding-command
+/// rule in PROTOCOL.md is required to keep solicited responses ordered.
+pub async fn route_command(
+    cmd: Command,
+    commands: &CommandChannel,
+    responses: &ResponseChannel,
+    display_commands: &DisplayCommandChannel,
+    has_display: bool,
+    mac: [u8; 6],
+) {
+    match cmd {
+        Command::DisplayOn => {
+            if has_display {
+                display_commands.send(DisplayCommand::On).await;
+                responses.send(Response::Ok).await;
+            } else {
+                responses.send(Response::Error(ErrorCode::NoDisplay)).await;
+            }
+        }
+        Command::DisplayOff => {
+            if has_display {
+                display_commands.send(DisplayCommand::Off).await;
+                responses.send(Response::Ok).await;
+            } else {
+                responses.send(Response::Error(ErrorCode::NoDisplay)).await;
+            }
+        }
+        Command::GetMac => {
+            responses.send(Response::MacAddress(mac)).await;
+        }
+        other => {
+            commands.send(other).await;
+        }
+    }
+}

firmware/src/uart/mod.rs

@@ -0,0 +1,4 @@
+//! UART interface with COBS-framed command/response protocol.
+
+mod task;
+pub use task::uart_task;

firmware/src/uart/task.rs

@@ -0,0 +1,73 @@
+//! UART task: COBS-framed fixed-size LE command/response protocol.
+//!
+//! Reads COBS frames from UART, decodes them, parses commands, routes them
+//! to the radio or display task, and sends COBS-framed responses back.
+//! Used for boards with USB-UART bridge chips (e.g. CP2102 on some Heltec V3).
+
+use defmt::warn;
+use embassy_executor::task;
+use embedded_io_async::Write;
+
+use crate::channel::{CommandChannel, DisplayCommandChannel, ResponseChannel};
+use crate::protocol_io::{self, FrameAccumulator, MAX_FRAME};
+
+#[task]
+pub async fn uart_task(
+    parts: crate::board::UartParts,
+    commands: &'static CommandChannel,
+    responses: &'static ResponseChannel,
+    display_commands: &'static DisplayCommandChannel,
+    has_display: bool,
+    mac: [u8; 6],
+) {
+    let (mut rx, mut tx) = parts.driver.split();
+
+    let mut read_buf = [0u8; 64];
+    let mut write_buf = [0u8; MAX_FRAME];
+    let mut cobs_encode_buf = [0u8; MAX_FRAME];
+    let mut accumulator = FrameAccumulator::new();
+
+    loop {
+        use embassy_futures::select::select;
+        use embassy_futures::select::Either;
+
+        match select(
+            embedded_io_async::Read::read(&mut rx, &mut read_buf),
+            responses.receive(),
+        )
+        .await
+        {
+            Either::First(result) => {
+                let n = match result {
+                    Ok(0) => continue,
+                    Ok(n) => n,
+                    Err(_) => {
+                        accumulator.reset();
+                        embassy_time::Timer::after_millis(100).await;
+                        continue;
+                    }
+                };
+
+                let mut cmds = heapless::Vec::<_, 4>::new();
+                accumulator.feed(&read_buf[..n], |cmd| {
+                    let _ = cmds.push(cmd);
+                });
+                for cmd in cmds {
+                    protocol_io::route_command(
+                        cmd, commands, responses, display_commands, has_display, mac,
+                    )
+                    .await;
+                }
+            }
+            Either::Second(response) => {
+                if let Some(frame) =
+                    protocol_io::encode_response(response, &mut write_buf, &mut cobs_encode_buf)
+                {
+                    if tx.write_all(frame).await.is_err() {
+                        warn!("UART write failed, response dropped");
+                    }
+                }
+            }
+        }
+    }
+}