Add dual-channel serial passthrough to userial by Copilot · Pull Request #1 · bring42/tbx

Copilot · 2026-04-28T08:16:47Z

Summary

add dual-channel UART support to tools/userial with default channel A pins on GPIO4/GPIO5 and channel B pins on GPIO6/GPIO7
add bridged passthrough controls, per-port monitoring, targeted ASCII/hex injection, and persisted serial settings/history support
refresh the userial web UI, mock data, generated web assets, and dev-server behavior for the new protocol
ignore generated dist/ output so local preview artifacts are not committed

Validation

python build/build_web.py --tool-dir tools/userial
python build/build_web.py --tool-dir tools/wifiscan
pio run -e xiao_esp32c3 (blocked by PlatformIO HTTPClientError while installing espressif32 in this environment)
sub-agent proofreading review completed and follow-up issues were fixed
parallel_validation completed with 0 CodeQL alerts

Agent-Logs-Url: https://github.com/bring42/tbx/sessions/2816ed76-19fb-4145-812b-d366a6770f48 Co-authored-by: bring42 <63049750+bring42@users.noreply.github.com>

Copilot

Pull request overview

Adds dual-channel UART monitoring/injection plus optional bidirectional passthrough bridging to the tools/userial ESP32 web-UI tool, along with updated dev-server mocks and refreshed UI assets.

Changes:

Extend firmware to support two UART channels (A/B), passthrough modes, per-port counters, and on-device history buffering.
Refresh userial web UI to show per-port traffic, filtering, injection targeting, and passthrough controls (plus updated mocks).
Improve dev server behavior for the new WS protocol and ignore local dist/ build artifacts.

Reviewed changes

Copilot reviewed 9 out of 11 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
tools/userial/web/mock_data.json	Updates mock payload schema for dual-port status/settings/history.
tools/userial/web/config.json	Renames tool title for the new dual-UART functionality.
tools/userial/web/app.js	Implements dual-port monitoring, filtering, export, and targeted injection logic.
tools/userial/web/app.html	Updates layout to show bridge status, per-port cards, and injection port selectors.
tools/userial/web/app.css	Adds styles for port badges/cards and refreshed monitor/toolbar layout.
tools/userial/src/main.cpp	Implements dual-UART firmware, passthrough forwarding, history ring buffer, and persisted serial settings.
tools/userial/src/_assembled.html	Regenerated assembled HTML including updated UI/JS/CSS (build output).
build/dev_server.py	Enhances mock WS server to emulate dual-port protocol + rewrites WS URL for split-port dev mode.
README.md	Updates tool description to reflect dual-UART bridging capabilities.
.gitignore	Ignores `dist/` directories to avoid committing local build previews.

Copilot · 2026-04-28T09:39:34Z

+        const entry = normalizeEntry({ ...data, dir: 'RX' });
+        addLogEntry(entry);
+        updateTrafficStats(data, true);
+        terminalAppend('[' + entry.port + '] ' + decodeDisplayText(entry.ascii) + '\n', 'rx-line');


RX handler normalizes the entry before calling addLogEntry(), but addLogEntry() normalizes again. This duplicates work on every message and makes it easier for the two normalization paths to drift. Consider either passing raw WS data into addLogEntry() (and separately normalizing only for terminal output) or updating addLogEntry() to accept already-normalized entries.

Copilot · 2026-04-28T09:39:34Z

+        const entry = normalizeEntry({ ...data, dir: 'RX' });
+        addLogEntry(entry);
+        updateTrafficStats(data, true);
+        terminalAppend('[' + entry.port + '] ' + decodeDisplayText(entry.ascii) + '\n', 'rx-line');


For RX events, decodeDisplayText(entry.ascii) converts preview sequences like "\n" back into real newlines, and then an additional "\n" is appended. If the payload preview already contains line endings, this produces extra blank lines in the terminal output (and reintroduces carriage returns). Consider either not decoding "\n"/"\r" for the terminal view, or only appending a newline when the decoded payload doesn’t already end with one.

Suggested change

terminalAppend('[' + entry.port + '] ' + decodeDisplayText(entry.ascii) + '\n', 'rx-line');

const rxText = decodeDisplayText(entry.ascii);

const rxLineEnding = /[\r\n]$/.test(rxText) ? '' : '\n';

terminalAppend('[' + entry.port + '] ' + rxText + rxLineEnding, 'rx-line');

Copilot · 2026-04-28T09:39:35Z

@@ -1,19 +1,101 @@
 /* RS-232 Serial Tool — specific styles */


The file header comment still says “RS-232 Serial Tool — specific styles”, but the tool has been renamed/repurposed to dual-UART. Updating this comment will help keep generated assets (_assembled.html) and future maintenance aligned with the current tool behavior.

Suggested change

/* RS-232 Serial Tool — specific styles */

/* Dual-UART Tool — specific styles */

Copilot · 2026-04-28T09:39:35Z

    Serial.println("\n  RS-232 Serial Tool ready.");
-    Serial.println("  Waiting for serial data...\n");
+    Serial.printf("  Channel A RX/TX: GPIO%u/GPIO%u\n", channels[0].rxPin, channels[0].txPin);


Startup log still prints “RS-232 Serial Tool ready.” even though the tool/UI/config have been renamed to Dual UART. Consider updating the Serial console banner so it matches the current tool name and avoids confusion when debugging.

Copilot · 2026-04-28T09:39:35Z

+HardwareSerial SerialChannelA(1);
+HardwareSerial SerialChannelB(0);
+ChannelState channels[] = {
+    {"A", "Channel A", SERIAL_A_RX_PIN, SERIAL_A_TX_PIN, &SerialChannelA, 0, 0},
+    {"B", "Channel B", SERIAL_B_RX_PIN, SERIAL_B_TX_PIN, &SerialChannelB, 0, 0},


Channel B is instantiated as HardwareSerial(0) and later initialized in beginChannel(). On ESP32 Arduino, Serial usually maps to UART0; reconfiguring UART0 (baud/pins) after Serial.begin(115200) can break the USB/serial console and any Serial logging used by toolbox_web/toolbox_wifi. Consider moving Channel B to a different UART index (e.g., 2) or explicitly separating the debug console from UART0 so Serial output remains stable.

Copilot · 2026-04-28T09:39:36Z

+    if (len == 0) return;
+    channels[channelIndex].uart->write(data, len);
+    channels[channelIndex].txBytes += len;
+    tbLedFlash();
+


tbLedFlash() is called immediately after every UART write. Since tbLedFlash() uses delay() (blocking), this can throttle high-throughput serial traffic, increase latency, and potentially cause UART RX buffer overflows/data loss during passthrough. Prefer a non-blocking LED activity indicator (e.g., set a timestamp/flag and blink in tbLedBlink) or make LED flashing conditional/throttled.

Copilot · 2026-04-28T09:39:36Z

+            channels[peerIndex].uart->write(buffer, count);
+            channels[peerIndex].txBytes += count;
+        }
+        tbLedFlash();
+        storeHistory(channel.id[0], 'R', forwarded ? channels[peerIndex].id[0] : 0, buffer, count, ts);


tbLedFlash() is called during RX handling (and also when forwarding to the peer UART). Since tbLedFlash() blocks via delay(), sustained traffic can slow the loop enough to starve tbWifiLoop()/tbWebLoop() and increase the risk of UART buffer overflow/data loss. Consider replacing this with a non-blocking activity indicator or throttling flashes (e.g., max once per N ms).

Copilot · 2026-04-28T09:39:36Z

+HistoryEntry history[HISTORY_SIZE];
+size_t historyHead = 0;
+size_t historyCount = 0;


PR description mentions persisted serial settings/history, but the firmware only persists serial settings (Preferences) while history is kept only in RAM (history[] ring buffer) and will be lost on reboot. If persistence across reboots is intended, history needs to be stored in Preferences/flash (with wear considerations); otherwise, update the PR description/UI copy to clarify that history is session-only.

Copilot AI and others added 5 commits April 28, 2026 07:51

Plan dual-channel serial passthrough work

a29e312

Agent-Logs-Url: https://github.com/bring42/tbx/sessions/2816ed76-19fb-4145-812b-d366a6770f48 Co-authored-by: bring42 <63049750+bring42@users.noreply.github.com>

Implement dual-channel userial firmware

1845cc0

Agent-Logs-Url: https://github.com/bring42/tbx/sessions/2816ed76-19fb-4145-812b-d366a6770f48 Co-authored-by: bring42 <63049750+bring42@users.noreply.github.com>

Update userial web UI for dual-channel bridge

2ac0b15

Agent-Logs-Url: https://github.com/bring42/tbx/sessions/2816ed76-19fb-4145-812b-d366a6770f48 Co-authored-by: bring42 <63049750+bring42@users.noreply.github.com>

Polish dual-channel passthrough validation fixes

89aa4f0

Agent-Logs-Url: https://github.com/bring42/tbx/sessions/2816ed76-19fb-4145-812b-d366a6770f48 Co-authored-by: bring42 <63049750+bring42@users.noreply.github.com>

Ignore generated dist output and finalize passthrough UI

6bcc656

Agent-Logs-Url: https://github.com/bring42/tbx/sessions/2816ed76-19fb-4145-812b-d366a6770f48 Co-authored-by: bring42 <63049750+bring42@users.noreply.github.com>

Copilot AI assigned Copilot and bring42 Apr 28, 2026

Copilot created this pull request from a session on behalf of bring42 April 28, 2026 08:17 View session

Copilot finished work on behalf of bring42 April 28, 2026 08:17

Copilot AI requested a review from bring42 April 28, 2026 08:17

bring42 requested a review from Copilot April 28, 2026 09:33

Copilot started reviewing on behalf of bring42 April 28, 2026 09:33 View session

Copilot AI reviewed Apr 28, 2026

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Add dual-channel serial passthrough to userial#1

Add dual-channel serial passthrough to userial#1
Copilot wants to merge 5 commits intomainfrom
copilot/add-serial-pass-through-functionality

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-        terminalAppend('[' + entry.port + '] ' + decodeDisplayText(entry.ascii) + '\n', 'rx-line');
+        const rxText = decodeDisplayText(entry.ascii);
+        const rxLineEnding = /[\r\n]$/.test(rxText) ? '' : '\n';
+        terminalAppend('[' + entry.port + '] ' + rxText + rxLineEnding, 'rx-line');

		@@ -1,19 +1,101 @@
		/* RS-232 Serial Tool — specific styles */

	/* RS-232 Serial Tool — specific styles */
	/* Dual-UART Tool — specific styles */

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