init: F3 unlock project — ESP32-C3 bridge + procedure for CLAR200 Exos X18

2026-06-14 21:12:56 -04:00
commit 947d5cfc40
10 changed files with 608 additions and 0 deletions
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+// clar200_bridge.ino — ESP32-C3 transparent USB <-> UART bridge
+// Purpose: talk to a Seagate F3 diagnostic terminal on an EMC CLAR200-locked
+//          Exos X18 SAS drive, using the C3's native USB-CDC as the host side.
+//
+// Target board: ESP32-C3 (native USB-Serial-JTAG), e.g. C3 SuperMini / DevKitM-1.
+// Host port:    /dev/ttyACM0 on steel141 (MAC 58:8c:81:ac:f0:4c).
+//
+// Build flag REQUIRED: "USB CDC On Boot: Enabled"  (so `Serial` == USB-CDC, not UART0)
+//   arduino-cli: append  :CDCOnBoot=cdc  to the FQBN (see firmware/flash.sh)
+//
+// Wiring (3.3 V, common ground, TX<->RX crossover):
+//   ESP32-C3 GPIO4 (DRV_TX) ---> drive F3 RX
+//   ESP32-C3 GPIO5 (DRV_RX) <--- drive F3 TX
+//   ESP32-C3 GND            ---- drive GND   (mandatory)
+//   Do NOT connect any VCC/5V to the drive header. Drive is powered by its own
+//   SATA/SAS power. You only tap TX / RX / GND.
+//
+// Baud: Seagate F3 is 8N1. Family varies — this sketch boots at 38400 and lets
+// you change baud live without reflashing, via a `~` escape menu (see below).
+//
+// Live baud menu — type these AT THE START OF A LINE in your terminal:
+//   ~1  -> 9600     ~2 -> 38400 (default)    ~3 -> 115200    ~4 -> 460800
+//   ~?  -> print current baud
+// Anything else is passed through transparently (binary-safe).
+
+#define DRV_TX   4          // ESP32-C3 GPIO -> drive RX
+#define DRV_RX   5          // ESP32-C3 GPIO <- drive TX
+#define LED_PIN  8          // most C3 boards: onboard LED on GPIO8 (active-low). Harmless if absent.
+
+static const uint32_t BAUDS[] = {9600, 38400, 115200, 460800};
+static uint32_t curBaud = 38400;
+
+static void applyBaud(uint32_t b) {
+  curBaud = b;
+  Serial1.end();
+  Serial1.begin(curBaud, SERIAL_8N1, DRV_RX, DRV_TX);
+  Serial.printf("\r\n[bridge] drive UART = %lu 8N1\r\n", (unsigned long)curBaud);
+}
+
+void setup() {
+  pinMode(LED_PIN, OUTPUT);
+  digitalWrite(LED_PIN, LOW);          // LED on = bridge alive
+  Serial.begin(115200);                // USB-CDC; baud value is ignored over CDC
+  delay(200);
+  applyBaud(38400);
+  Serial.print("\r\n[bridge] ESP32-C3 F3 bridge ready. ~1/~2/~3/~4 set baud, ~? shows it.\r\n");
+}
+
+// Minimal line-start escape parser so `~N` switches baud but everything else
+// (including F3 binary) flows through untouched.
+static bool atLineStart = true;
+static bool inEscape = false;
+
+void loop() {
+  // host -> drive
+  while (Serial.available()) {
+    int c = Serial.read();
+    if (inEscape) {
+      inEscape = false;
+      switch (c) {
+        case '1': applyBaud(BAUDS[0]); break;
+        case '2': applyBaud(BAUDS[1]); break;
+        case '3': applyBaud(BAUDS[2]); break;
+        case '4': applyBaud(BAUDS[3]); break;
+        case '?': Serial.printf("\r\n[bridge] current = %lu\r\n", (unsigned long)curBaud); break;
+        default:  // not a menu key: emit the swallowed '~' then this char
+          Serial1.write('~'); Serial1.write((uint8_t)c);
+      }
+      atLineStart = false;
+      continue;
+    }
+    if (atLineStart && c == '~') { inEscape = true; continue; }
+    Serial1.write((uint8_t)c);
+    atLineStart = (c == '\n' || c == '\r');
+  }
+  // drive -> host
+  while (Serial1.available()) Serial.write((uint8_t)Serial1.read());
+}
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+#!/usr/bin/env bash
+# flash.sh — build + flash the ESP32-C3 F3 bridge from steel141.
+# The C3 is at /dev/ttyACM0 (native USB-Serial-JTAG). esptool is already present;
+# arduino-cli + the esp32 core are installed on first run if missing.
+set -euo pipefail
+
+PORT="${1:-/dev/ttyACM0}"
+SKETCH="$(cd "$(dirname "$0")" && pwd)/clar200_bridge.ino"
+FQBN="esp32:esp32:esp32c3:CDCOnBoot=cdc"   # CDCOnBoot=cdc -> Serial == USB-CDC (required by sketch)
+
+command -v arduino-cli >/dev/null 2>&1 || {
+  echo ">> installing arduino-cli to ~/.local/bin ..."
+  mkdir -p ~/.local/bin
+  curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh \
+    | BINDIR=~/.local/bin sh
+  export PATH="$HOME/.local/bin:$PATH"
+}
+
+if ! arduino-cli core list 2>/dev/null | grep -q '^esp32:esp32'; then
+  echo ">> installing esp32 Arduino core (this is the big download) ..."
+  arduino-cli config init --overwrite >/dev/null 2>&1 || true
+  arduino-cli config add board_manager.additional_urls \
+    https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json
+  arduino-cli core update-index
+  arduino-cli core install esp32:esp32
+fi
+
+# arduino-cli wants the sketch in a dir named like the .ino; it already is.
+SKETCH_DIR="$(dirname "$SKETCH")"
+echo ">> compiling for $FQBN ..."
+arduino-cli compile --fqbn "$FQBN" "$SKETCH_DIR"
+
+echo ">> flashing to $PORT ..."
+arduino-cli upload --fqbn "$FQBN" --port "$PORT" "$SKETCH_DIR"
+
+echo ">> done. Open the terminal with:  screen $PORT 115200   (Ctrl-A k to quit)"
+echo "   USB-CDC baud is virtual; set the DRIVE baud with ~1/~2/~3/~4 inside the session."