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--- tamiwiki:users:6r1d:diymall_esp32_s3_fixture [2025/10/18 17:49] – 6r1d
+++ tamiwiki:users:6r1d:diymall_esp32_s3_fixture [2025/10/20 05:43] (current) – [ESP-IDF (+ history and PWM debug)] 6r1d
@@ Line 1: / Line 1: @@
-There's something very nice about ESP32 Wroom modules: you can use fixtures to quickly debug things, remove a module, solder it and viola, you have something working.
+There’s something great about [[https://www.espressif.com/en/products/socs/esp32-s3|ESP32-WROOM]] modules: you can prototype fast, use test fixtures to debug, then pop a module off, solder it onto a board, and voilà, you’ve got a working device.
-Or a bad board. Mostly those options.
+Or a non-working one.
+//Usually// it's one of those two.
-And I've been using a fixture by [[http://www.diymalls.com/|DIYMall]] for some time at this point. From my perspective, its main feature is the support for ESP32-S3-WROOM-1U and ESP32-S3-WROOM-1 ([[https://www.espressif.com/sites/default/files/documentation/esp32-s3-wroom-1_wroom-1u_datasheet_en.pdf|datasheet]]).
+====== Introduction ======
+I've been using a fixture by [[http://www.diymalls.com/|DIYMall]] for some time at this point. From my perspective, its main feature is the support for ESP32-S3-WROOM-1U and ESP32-S3-WROOM-1 ([[https://www.espressif.com/sites/default/files/documentation/esp32-s3-wroom-1_wroom-1u_datasheet_en.pdf|datasheet]]).
 {{:tamiwiki:users:6r1d:signal-2025-10-18-123252_002.jpeg?400|}} {{:tamiwiki:users:6r1d:signal-2025-10-18-123334_002.jpeg?400|}}
-It is very helpful as a fixture. It is not helpful whatsoever in terms of having a proper documentation. If you open the DIYMalls site, it shows 403 and doesn't give you anything.
+It is very helpful as a fixture. It is not helpful whatsoever when it comes to proper documentation. If you open the [[http://diymalls.com/|DIYMalls site]], it shows a 403 and gives you nothing.
 So, the fixture is easy to buy on AliExpress, for example, [[https://aliexpress.com/item/1005008525778779.html|here]], it works without hassle, and it will also require you trace all pins unless you have a reference.
 Thus, I've traced everything I found so you don't have to.
+====== Pin assignments ======
 ^ ESP32-S3-Wroom contact pad ^ Datasheet reference ^ Arduino pin ^ Board pin ^
@@ Line 41: / Line 46: @@
 | 37                         | TXD0                | 37          | D34       |
-If you'd like to make corrections or are unhappy with how I wrote this tiny article, ping me in [[https://t.me/I_am_6r1d|Telegram]].
+===== Notes =====
+  * GPIO pin 48 is the onboard LED, usually blue.
+  * Initially, I thought that onboard USB-UART is connected to something else than RXD0 / TXD0. It was not. It is the main UART.
+====== Tracing code ======
+You might disagree with me and want to double-check. Excellent! More eyes (and feedback) mean better information.
+Grab your trusty 30-year-old LED soldered to a pair of DuPont sockets and start tracing. If you don’t have one handy (like me), grab your scope instead.((Marie Antoinette reference unintended.))
+For convenience, here’s the code to do the job. I didn’t bother writing it from scratch, but I tested it, and it worked just fine for me.
+===== ESP-IDF (+ history and PWM debug) =====
+This code gives you a predictable interactive workflow with history.
+<code>
+> help
+Commands:
+  list                          -> show test-safe GPIOs
+  status                        -> show current pin/mode
+  pin <gpio>                    -> start blinking GPIO
+  <gpio>                        -> same as 'pin <gpio>'
+  delay <ms>                    -> set blink delay
+  pwm <pin> [brightness]        -> start PWM (0-99, current: 50%)
+  brightness <level>            -> set PWM brightness (0-99)
+  freq <frequency>              -> set PWM frequency (Hz)
+  stop                          -> stop and release pin
+> 48
+Stopped. Pin released to INPUT.
+Blinking GPIO 48 at 100 ms.
+> 42
+Stopped. Pin released to INPUT.
+Blinking GPIO 42 at 100 ms.
+> 47
+Stopped. Pin released to INPUT.
+Blinking GPIO 47 at 100 ms.
+> 46
+Restricted: GPIO 46 is not in the test-safe set.
+> delay 40
+Set blink delay to 40 ms.
+> delay 10
+Set blink delay to 10 ms.
+</code>
+As for using it, you should know the gist at this point.
+<code bash>
+mkdir pin_tracer && cd pin_tracer
+idf.py create-project . && idf.py reconfigure && idf.py set-target esp32s3
+# fill the code
+# update the CMake configs
+idf.py build
+idf.py flash monitor
+</code>
+For your convenience, I have shared the whole [[https://git.telavivmakers.space/6r1d/esp32_s3_pin_tracer_espidf|repository]] at TAMI Gitea.
+Clone it like that:
+<code bash>
+git clone https://git.telavivmakers.space/6r1d/esp32_s3_pin_tracer_espidf.git esp32_s3_pin_tracer
+</code>
+Also, you can use Minicom to interact with the tracing code if you'd like. It's just one of the default baudrates, 115200.
+<code bash>
+minicom -D /dev/ttyUSB0 -b 115200 -o
+</code>
+===== Arduino (basic version) =====
+Flash from Arduino IDE. Use the ESP32 board package by Espressif, pick ESP32S3 Dev Module, pick 115200 baud in Serial Monitor.
+<file cpp esp32_s3_pin_tracer.ino>
+#include <Arduino.h>
+// ====== CONFIG ======
+// Blink timing (change at runtime with: delay <ms>)
+static uint32_t BLINK_DELAY_MS = 100;
+// Conservative "test-safe GPIO" set for ESP32-S3 modules.
+// Excludes pins that commonly serve boot strapping, USB D-/D+, PSRAM/flash, UART0 console, or JTAG,
+// which can interfere with programming, boot, or board-level functions during quick tests.
+//
+// Notes (summarized from the ESP32-S3 module/chip docs):
+// - 0, 3, 45, 46 are strapping/boot-related or JTAG-related; driving them can change boot modes or disable debug.
+// - 19, 20 are the on-chip USB D-/D+ differential pair; toggling them breaks USB comms.
+// - 35, 36, 37 are wired to Octal PSRAM on some variants; not available as GPIO there.
+// - 43 (U0TXD), 44 (U0RXD) are UART0 console pins used by Serial; poking them disrupts logs/flashing.
+// - 47, 48 form a differential SPI clock pair; safe as GPIO but mind 1.8 V I/O level on some R16V variants.
+const uint8_t TEST_SAFE_GPIO[] = {
+, 2,                      // ADC/Touch-capable, OK for digital use
+, 5, 6, 7,                // "
+, 9, 10, 11, 12, 13, 14,  // "
+, 16, 17, 18,            // "
+  // 19,20 excluded (USB D-/D+)
+,  // plain GPIO
+  // 22..34 don't exist on S3 modules
+  // 35,36,37 excluded (PSRAM on some variants)
+, 39, 40, 41, 42,  // JTAG-capable if configured, but OK as GPIO when JTAG is not in use
+  // 43,44 excluded (UART0 TX/RX used by Serial)
+, 48  // differential clock pair; OK as GPIO (watch 1.8 V I/O on some R16V variants)
+};
+const size_t TEST_SAFE_GPIO_COUNT = sizeof(TEST_SAFE_GPIO) / sizeof(TEST_SAFE_GPIO[0]);
+// ====== RUNTIME STATE ======
+static int currentPin = -1;
+static bool blinking = false;
+// ====== HELPERS ======
+bool isTestSafe(int gpio) {
+  for (size_t i = 0; i < TEST_SAFE_GPIO_COUNT; ++i) {
+    if ((int)TEST_SAFE_GPIO[i] == gpio) return true;
+  }
+  return false;
+}
+void printTestSafePins() {
+  Serial.println(F("\nTest-safe GPIOs (ESP32-S3):"));
+  for (size_t i = 0; i < TEST_SAFE_GPIO_COUNT; ++i) {
+    Serial.print(F(i ? ", " : "  "));
+    Serial.print(TEST_SAFE_GPIO[i]);
+  }
+  Serial.println();
+  Serial.println(F("Excluded (reason): 0,3,45,46 (boot/strap/JTAG) | 19,20 (USB D-/D+) | 35-37 (PSRAM on some) | 43,44 (UART0 console)"));
+}
+void stopBlink() {
+  if (currentPin >= 0) {
+    digitalWrite(currentPin, LOW);
+    pinMode(currentPin, INPUT);  // leave safe
+  }
+  blinking = false;
+  currentPin = -1;
+  Serial.println(F("Stopped. Pin released to INPUT."));
+}
+void startBlink(int gpio) {
+  if (!isTestSafe(gpio)) {
+    Serial.print(F("Restricted: GPIO "));
+    Serial.print(gpio);
+    Serial.println(F(" is not in the test-safe set."));
+    return;
+  }
+  if (blinking && currentPin == gpio) {
+    Serial.print(F("Already blinking GPIO "));
+    Serial.println(gpio);
+    return;
+  }
+  // switch pin if needed
+  if (blinking && currentPin != gpio) stopBlink();
+  currentPin = gpio;
+  pinMode(currentPin, OUTPUT);
+  digitalWrite(currentPin, LOW);
+  blinking = true;
+  Serial.print(F("Blinking GPIO "));
+  Serial.print(currentPin);
+  Serial.print(F(" at "));
+  Serial.print(BLINK_DELAY_MS);
+  Serial.println(F(" ms."));
+}
+// Parse commands like:
+//   list
+//   pin 10
+//   delay 250
+//   stop
+void handleCommand(String line) {
+  line.trim();
+  if (line.length() == 0) return;
+  line.toLowerCase();
+  if (line == "list") {
+    printTestSafePins();
+    return;
+  }
+  if (line == "stop") {
+    stopBlink();
+    return;
+  }
+  if (line.startsWith("pin ")) {
+    int gpio = line.substring(4).toInt();
+    startBlink(gpio);
+    return;
+  }
+  if (line.startsWith("delay ")) {
+    int v = line.substring(6).toInt();
+    if (v < 10) v = 10;  // clamp a bit
+    BLINK_DELAY_MS = (uint32_t)v;
+    Serial.print(F("Set blink delay to "));
+    Serial.print(BLINK_DELAY_MS);
+    Serial.println(F(" ms."));
+    return;
+  }
+  // Single-number shortcut: just type the GPIO number
+  bool allDigits = true;
+  for (size_t i = 0; i < (size_t)line.length(); ++i) {
+    if (!isDigit(line[i])) {
+      allDigits = false;
+      break;
+    }
+  }
+  if (allDigits) {
+    startBlink(line.toInt());
+    return;
+  }
+  Serial.println(F("Commands:"));
+  Serial.println(F("  list               -> show test-safe GPIOs"));
+  Serial.println(F("  pin <gpio>         -> start blinking that GPIO"));
+  Serial.println(F("  <gpio>             -> same as 'pin <gpio>'"));
+  Serial.println(F("  delay <ms>         -> set blink delay"));
+  Serial.println(F("  stop               -> stop and release pin"));
+}
+void setup() {
+  Serial.begin(115200);
+  // give USB-Serial/JTAG a moment
+  delay(400);
+  Serial.println(F("\nESP32-S3 GPIO Quick Tester"));
+  Serial.println(F("Type 'list' to see test-safe pins, 'pin <gpio>' to blink, 'delay <ms>' to change speed, 'stop' to release.\n"));
+  printTestSafePins();
+}
+void loop() {
+  // Process serial line input
+  static String line;
+  while (Serial.available()) {
+    char c = (char)Serial.read();
+    if (c == '\r') continue;
+    if (c == '\n') {
+      handleCommand(line);
+      line = "";
+    } else {
+      line += c;
+    }
+  }
+  // Blink the selected pin
+  if (blinking && currentPin >= 0) {
+    digitalWrite(currentPin, HIGH);
+    delay(BLINK_DELAY_MS);
+    digitalWrite(currentPin, LOW);
+    delay(BLINK_DELAY_MS);
+  } else {
+    delay(5);
+  }
+}
+</file>
+====== Feedback ======
+If you’d like to suggest corrections or aren’t satisfied with how I wrote this short article, feel free to ping me on [[https://t.me/I_am_6r1d|Telegram]].
-This topic possibly deserves to be a more widely shown form of a doc. Then again, IDK if anyone uses S3 that much around.
+This topic might deserve to be expanded into a document outside of my personal page.
+Then again, I’m not sure how many people around here actually use ESP32-S3.

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