79 lines
3.1 KiB
Arduino
79 lines
3.1 KiB
Arduino
// clar200_bridge.ino — ESP32-C3 transparent USB <-> UART bridge
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// Purpose: talk to a Seagate F3 diagnostic terminal on an EMC CLAR200-locked
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// Exos X18 SAS drive, using the C3's native USB-CDC as the host side.
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//
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// Target board: ESP32-C3 (native USB-Serial-JTAG), e.g. C3 SuperMini / DevKitM-1.
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// Host port: /dev/ttyACM0 on steel141 (MAC 58:8c:81:ac:f0:4c).
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//
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// Build flag REQUIRED: "USB CDC On Boot: Enabled" (so `Serial` == USB-CDC, not UART0)
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// arduino-cli: append :CDCOnBoot=cdc to the FQBN (see firmware/flash.sh)
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//
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// Wiring (3.3 V, common ground, TX<->RX crossover):
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// ESP32-C3 GPIO4 (DRV_TX) ---> drive F3 RX
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// ESP32-C3 GPIO5 (DRV_RX) <--- drive F3 TX
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// ESP32-C3 GND ---- drive GND (mandatory)
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// Do NOT connect any VCC/5V to the drive header. Drive is powered by its own
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// SATA/SAS power. You only tap TX / RX / GND.
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//
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// Baud: Seagate F3 is 8N1. Family varies — this sketch boots at 38400 and lets
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// you change baud live without reflashing, via a `~` escape menu (see below).
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//
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// Live baud menu — type these AT THE START OF A LINE in your terminal:
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// ~1 -> 9600 ~2 -> 38400 (default) ~3 -> 115200 ~4 -> 460800
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// ~? -> print current baud
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// Anything else is passed through transparently (binary-safe).
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#define DRV_TX 4 // ESP32-C3 GPIO -> drive RX
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#define DRV_RX 5 // ESP32-C3 GPIO <- drive TX
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#define LED_PIN 8 // most C3 boards: onboard LED on GPIO8 (active-low). Harmless if absent.
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static const uint32_t BAUDS[] = {9600, 38400, 115200, 460800};
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static uint32_t curBaud = 38400;
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static void applyBaud(uint32_t b) {
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curBaud = b;
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Serial1.end();
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Serial1.begin(curBaud, SERIAL_8N1, DRV_RX, DRV_TX);
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Serial.printf("\r\n[bridge] drive UART = %lu 8N1\r\n", (unsigned long)curBaud);
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}
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void setup() {
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pinMode(LED_PIN, OUTPUT);
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digitalWrite(LED_PIN, LOW); // LED on = bridge alive
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Serial.begin(115200); // USB-CDC; baud value is ignored over CDC
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delay(200);
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applyBaud(38400);
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Serial.print("\r\n[bridge] ESP32-C3 F3 bridge ready. ~1/~2/~3/~4 set baud, ~? shows it.\r\n");
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}
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// Minimal line-start escape parser so `~N` switches baud but everything else
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// (including F3 binary) flows through untouched.
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static bool atLineStart = true;
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static bool inEscape = false;
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void loop() {
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// host -> drive
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while (Serial.available()) {
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int c = Serial.read();
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if (inEscape) {
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inEscape = false;
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switch (c) {
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case '1': applyBaud(BAUDS[0]); break;
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case '2': applyBaud(BAUDS[1]); break;
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case '3': applyBaud(BAUDS[2]); break;
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case '4': applyBaud(BAUDS[3]); break;
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case '?': Serial.printf("\r\n[bridge] current = %lu\r\n", (unsigned long)curBaud); break;
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default: // not a menu key: emit the swallowed '~' then this char
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Serial1.write('~'); Serial1.write((uint8_t)c);
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}
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atLineStart = false;
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continue;
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}
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if (atLineStart && c == '~') { inEscape = true; continue; }
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Serial1.write((uint8_t)c);
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atLineStart = (c == '\n' || c == '\r');
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}
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// drive -> host
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while (Serial1.available()) Serial.write((uint8_t)Serial1.read());
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}
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