ESP32-C6 Tang Bridge — UART-to-IRC Fleet Agent

RISC-V microcontroller (Seeed XIAO ESP32-C6) bridging Tang FPGA console UART to IRC.

Hardware

Tang Console UART TX/RX ──── ESP32-C6 XIAO ──── WiFi ──── Ergo IRC
     (3.3V, no level shifter needed)        (AERO SSID)   (10.0.3.203:6667)

• MCU: ESP32-C6, single-core RISC-V 160MHz, 512KB SRAM, 4MB flash
• WiFi: 802.11b/g/n 2.4GHz (CYW43439 equivalent)
• UART: GPIO 20 (RX from Tang), GPIO 21 (TX to Tang), 115200 baud
• USB: /dev/cu.usbmodem214401 on studio (MAC 58:8c:81:5d:22:70)
• IRC nick: tang-bridge in #agents

Architecture

NOT ii-agent. Custom C firmware using ESP-IDF. The ESP32-C6 is too constrained for Zig/ii-agent. It runs a minimal IRC client that:

1. Connects to WiFi (AERO SSID)
2. Opens TCP to Ergo IRC at 10.0.3.203:6667 (plaintext — no TLS, not enough RAM)
3. Registers as tang-bridge, joins #agents
4. Forwards UART RX from Tang Console to IRC as [tang] <text>
5. Forwards IRC messages to UART TX for Tang Console display
6. WireGuard tunnel support (trombik/esp_wireguard, BSD-3-Clause)

Project Location

/Users/studio/rust-town/esp32-tang-bridge/

Build

Requires: ESP-IDF v5.3+ (RISC-V toolchain for esp32c6)

# ESP-IDF setup (one-time)
cd ~/esp/esp-idf && source export.sh

# Build
cd ~/rust-town/esp32-tang-bridge
idf.py set-target esp32c6
idf.py build

Build boxes:

• studio (macOS): ESP-IDF v5.3.0 installed at ~/esp/esp-idf — works now
• pop4090 (Linux): ESP-IDF installing in background — use for future builds
• i9-zfs-pop, i7-zfs-pop: no ESP-IDF

Common build issues:

• Stale CMake cache from old path: idf.py fullclean then rebuild
• Component namespace: use trombik/esp_wireguard (slash), not trombik__esp_wireguard (double underscore)

Flash

ESP32-C6 is physically connected to studio via USB.

cd ~/rust-town/esp32-tang-bridge
source ~/esp/esp-idf/export.sh
idf.py -p /dev/cu.usbmodem214401 flash

# Monitor serial output
idf.py -p /dev/cu.usbmodem214401 monitor

Flash partitions:

• 0x0: bootloader
• 0x8000: partition table
• 0x10000: app (tang-bridge.bin, ~877KB, 16% free on partition)

Configuration

WiFi and IRC settings in sdkconfig (menuconfig) or main/main.c:

CONFIG_IDF_TARGET="esp32c6"
CONFIG_IDF_TARGET_ARCH="riscv"

• WiFi SSID: AERO (credentials in sdkconfig)
• IRC server: 10.0.3.203:6667 (plaintext)
• IRC nick: tang-bridge
• IRC channel: #agents
• UART baud: 115200

Wiring

Tang Console          ESP32-C6 XIAO
-----------           -------------
UART TX  ──────────>  GPIO 20 (RX)
UART RX  <──────────  GPIO 21 (TX)
GND      ──────────>  GND

Both 3.3V logic — no level shifter needed.

Ansible

The ESP32-C6 is NOT SSH-managed. It's in the inventory for documentation only:

[esp32]
tang-bridge ansible_host=TBD ansible_python_interpreter=/usr/bin/false # ESP32-C6 RISC-V, UART-IRC bridge, not SSH-managed

Build and flash operations happen on studio or build boxes, not via Ansible to the device.

License

• ESP-IDF: Apache-2.0
• trombik/esp_wireguard: BSD-3-Clause
• Project code: MIT

No GPL dependencies.

Related Skills

• atem-mini — HDMI switching for the Tang Console video
• fleet-irc — IRC protocol, Ergo server
• zig-cc — cross-compile for other targets (NOT used for ESP32-C6)