Add ESP32 JBD BMS read test sketch

tools/esp32_jbd_read_test/esp32_jbd_read_test.ino

@@ -0,0 +1,114 @@
+#include <NimBLEDevice.h>
+
+static const char* TARGET_ADDRESS = "a5:c2:37:2c:05:dc";
+
+static NimBLERemoteCharacteristic* notifyChar = nullptr;
+static NimBLERemoteCharacteristic* writeChar = nullptr;
+
+static bool gotNotification = false;
+
+uint8_t JBD_STATUS_REQUEST[] = {
+  0xDD, 0xA5, 0x03, 0x00, 0xFF, 0xFD, 0x77
+};
+
+void printHex(const uint8_t* data, size_t length) {
+  for (size_t i = 0; i < length; i++) {
+    if (data[i] < 0x10) Serial.print("0");
+    Serial.print(data[i], HEX);
+    Serial.print(" ");
+  }
+  Serial.println();
+}
+
+void notifyCallback(
+  NimBLERemoteCharacteristic* characteristic,
+  uint8_t* data,
+  size_t length,
+  bool isNotify
+) {
+  Serial.print("Notification length: ");
+  Serial.println(length);
+
+  Serial.print("Raw: ");
+  printHex(data, length);
+
+  gotNotification = true;
+}
+
+void setup() {
+  Serial.begin(115200);
+  delay(1000);
+
+  Serial.println();
+  Serial.println("=== ESP32 JBD Read Test ===");
+  Serial.print("Target: ");
+  Serial.println(TARGET_ADDRESS);
+
+  NimBLEDevice::init("XterraESP32");
+  NimBLEDevice::setPower(ESP_PWR_LVL_P9);
+
+  NimBLEAddress address(std::string(TARGET_ADDRESS), BLE_ADDR_PUBLIC);
+  NimBLEClient* client = NimBLEDevice::createClient();
+
+  Serial.println("Connecting...");
+  if (!client->connect(address)) {
+    Serial.println("Connect failed.");
+    return;
+  }
+
+  Serial.println("Connected.");
+
+  NimBLERemoteService* service = client->getService("ff00");
+  if (!service) {
+    Serial.println("Service ff00 not found.");
+    client->disconnect();
+    return;
+  }
+
+  notifyChar = service->getCharacteristic("ff01");
+  writeChar = service->getCharacteristic("ff02");
+
+  if (!notifyChar) {
+    Serial.println("Notify characteristic ff01 not found.");
+    client->disconnect();
+    return;
+  }
+
+  if (!writeChar) {
+    Serial.println("Write characteristic ff02 not found.");
+    client->disconnect();
+    return;
+  }
+
+  Serial.println("Subscribing to notifications...");
+  if (!notifyChar->subscribe(true, notifyCallback)) {
+    Serial.println("Subscribe failed.");
+    client->disconnect();
+    return;
+  }
+
+  delay(500);
+
+  Serial.print("Sending status request: ");
+  printHex(JBD_STATUS_REQUEST, sizeof(JBD_STATUS_REQUEST));
+
+  bool ok = writeChar->writeValue(
+    JBD_STATUS_REQUEST,
+    sizeof(JBD_STATUS_REQUEST),
+    false
+  );
+
+  Serial.print("Write result: ");
+  Serial.println(ok ? "OK" : "FAILED");
+
+  Serial.println("Waiting for notification...");
+}
+
+void loop() {
+  if (!gotNotification) {
+    delay(100);
+    return;
+  }
+
+  delay(5000);
+}