Replace JP_STRICT build flag with runtime frequency detection

JP LBT mode now activates automatically based on operating frequency:
- CH25: 920.800MHz
- CH26: 921.000MHz
- CH27: 921.200MHz (ARIB STD-T108, 200kHz grid)

Changes:
- Add isJapanMode() to RadioLibWrapper using getFreqMHz()
- Add getFreqMHz() to CustomSX1262Wrapper and CustomLR1110Wrapper
- Remove #ifdef JP_STRICT throughout, replaced by isJapanMode()
- Remove -D JP_STRICT build flag from platformio.ini
- MAX_TEXT_LEN dynamically determined by CR at runtime via getMaxTextLen()

No build flags required: JP compliance activates automatically
when device is configured to Japan 3 frequencies.

Author: jirogit

src/Dispatcher.h

@@ -38,9 +38,7 @@ class Radio {
 
   virtual float packetScore(float snr, int packet_len) = 0;
 
-#ifdef JP_STRICT
-  virtual int getMaxTextLen() const { return 1 * 16; }  // default: CR4/8
-#endif
+  virtual int getMaxTextLen() const { return 10 * 16; }  // default: non-JP
 
   /**
    * \brief  starts the raw packet send. (no wait)

src/helpers/BaseChatMesh.cpp

@@ -395,16 +395,9 @@ void BaseChatMesh::onGroupDataRecv(mesh::Packet* packet, uint8_t type, const mes
 
 mesh::Packet* BaseChatMesh::composeMsgPacket(const ContactInfo& recipient, uint32_t timestamp, uint8_t attempt, const char *text, uint32_t& expected_ack) {
   int text_len = strlen(text);
-
-#ifdef JP_STRICT
   int max_len = _radio->getMaxTextLen();
   if (text_len > max_len) return NULL;
   if (attempt > 3 && text_len > max_len - 2) return NULL;
-#else
-  if (text_len > MAX_TEXT_LEN) return NULL;
-  if (attempt > 3 && text_len > MAX_TEXT_LEN-2) return NULL;
-#endif
-
   uint8_t temp[5+MAX_TEXT_LEN+1];
   memcpy(temp, &timestamp, 4);   // mostly an extra blob to help make packet_hash unique
   temp[4] = (attempt & 3);

src/helpers/radiolib/CustomLR1110Wrapper.h

@@ -35,4 +35,7 @@ class CustomLR1110Wrapper : public RadioLibWrapper {
   uint8_t getCodingRate() const override {
     return ((CustomLR1110 *)_radio)->getCodingRate();
   }
+  float getFreqMHz() const override {
+    return ((CustomLR1110 *)_radio)->getFreqMHz();
+  }
 };

src/helpers/radiolib/CustomSX1262Wrapper.h

@@ -40,4 +40,7 @@ class CustomSX1262Wrapper : public RadioLibWrapper {
   uint8_t getCodingRate() const override {
     return ((CustomSX1262 *)_radio)->codingRate + 4;  // RadioLib stores 1-4, return 5-8
   }
+  float getFreqMHz() const override {
+    return ((CustomSX1262 *)_radio)->freqMHz;
+  }
 };

src/helpers/radiolib/RadioLibWrappers.cpp

@@ -169,10 +169,10 @@ bool RadioLibWrapper::isSendComplete() {
 void RadioLibWrapper::onSendFinished() {
   _radio->finishTransmit();
   _board->onAfterTransmit();
-#ifdef JP_STRICT
-  // ARIB STD-T108: wait >= 50ms after TX before next transmission
-  delay(50);
-#endif
+  if (isJapanMode()) {
+    // ARIB STD-T108: wait >= 50ms after TX before next transmission
+    delay(50);
+  }
   state = STATE_IDLE;
 }
 
@@ -183,40 +183,39 @@ int16_t RadioLibWrapper::performChannelScan() {
 bool RadioLibWrapper::isChannelActive() {
   if (_threshold == 0) return false;    // interference check is disabled
 
-#ifdef JP_STRICT
-  // ARIB STD-T108 compliant LBT: continuous RSSI sensing for >= 5ms
-  // Energy-based sensing required; LoRa CAD not used here —
-  // CAD detects only LoRa preambles and is not required by ARIB STD-T108
-  uint32_t sense_start = millis();
-  while (millis() - sense_start < 5) {
-    if (getCurrentRSSI() > -80.0f) {
-      // Channel busy: exponential backoff (tuned for JP 4s airtime)
-      _busy_count++;
-      uint32_t base_ms = 2000;
-      uint32_t max_backoff = min(base_ms * (1u << _busy_count), (uint32_t)16000);
-      uint32_t backoff_until = millis() + random(max_backoff / 2, max_backoff);
-      while (millis() < backoff_until) {
-        vTaskDelay(1);  // yield CPU to FreeRTOS tasks including BLE
+  // Activate JP_STRICT LBT on Japan 920MHz band 3 channels only
+  // CH25=920.800MHz, CH26=921.000MHz, CH27=921.200MHz (ARIB STD-T108)
+  if (isJapanMode()) {
+    // ARIB STD-T108 compliant LBT: continuous RSSI sensing for >= 5ms
+    // Energy-based sensing required; LoRa CAD not used 
+    uint32_t sense_start = millis();
+    while (millis() - sense_start < 5) {
+      if (getCurrentRSSI() > -80.0f) {
+        // Channel busy: exponential backoff (tuned for JP 4s airtime)
+        _busy_count++;
+        uint32_t base_ms = 2000;
+        uint32_t max_backoff = min(base_ms * (1u << _busy_count), (uint32_t)16000);
+        uint32_t backoff_until = millis() + random(max_backoff / 2, max_backoff);
+        while (millis() < backoff_until) {
+          vTaskDelay(1);
+        }
+        return true;
       }
-      return true;
+      vTaskDelay(1);
     }
-    vTaskDelay(1);  // yield CPU between RSSI samples
-  }
-  // Channel free: reset busy counter and add small jitter
-  _busy_count = 0;
-  uint32_t jitter_until = millis() + random(0, 500);
-  while (millis() < jitter_until) {
-    vTaskDelay(1);  // yield CPU to FreeRTOS tasks including BLE
+    // Channel free: reset busy counter and add small jitter
+    _busy_count = 0;
+    uint32_t jitter_until = millis() + random(0, 500);
+    while (millis() < jitter_until) {
+      vTaskDelay(1);
+    }
+    return false;
   }
-  return false;
 
-#else
   // Non-JP: original behavior (RSSI threshold only)
   return getCurrentRSSI() > _noise_floor + _threshold;
-#endif
 }
 
-
 float RadioLibWrapper::getLastRSSI() const {
   return _radio->getRSSI();
 }

src/helpers/radiolib/RadioLibWrappers.h

@@ -40,16 +40,23 @@ class RadioLibWrapper : public mesh::Radio {
 
   virtual float getCurrentRSSI() =0;
   virtual uint8_t getCodingRate() const = 0;
+  virtual float getFreqMHz() const = 0;
+
+  bool isJapanMode() const {
+    float freq = getFreqMHz();
+    return (fabsf(freq - 920.800f) < 0.05f ||
+            fabsf(freq - 921.000f) < 0.05f ||
+            fabsf(freq - 921.200f) < 0.05f);
+  }
 
-#ifdef JP_STRICT
   int getMaxTextLen() const {
+    if (!isJapanMode()) return 10 * 16;  // default
     uint8_t cr = getCodingRate();
-    if (cr <= 5) return 3 * 16;  // 48 bytes ~16 JP chars
-    if (cr == 6) return 2 * 16;  // 32 bytes ~10 JP chars
+    if (cr <= 5) return 3 * 16;   // 48 bytes ~16 JP chars
+    if (cr == 6) return 2 * 16;   // 32 bytes ~10 JP chars
     if (cr == 7) return 1 * 16 + 8; // 24 bytes ~8 JP chars
-    return 1 * 16;               // 16 bytes ~5 JP chars
+    return 1 * 16;                 // 16 bytes ~5 JP chars
   }
-#endif
 
   virtual int16_t performChannelScan();
 

variants/rak_wismesh_tag/platformio.ini

@@ -25,8 +25,6 @@ build_flags = ${nrf52_base.build_flags}
   -D PIN_BUZZER=21
   -D PIN_BOARD_SDA=PIN_WIRE_SDA
   -D PIN_BOARD_SCL=PIN_WIRE_SCL
-  -D JP_STRICT
-  -D LORA_CR=5
 build_src_filter = ${nrf52_base.build_src_filter}
   +<../variants/rak_wismesh_tag>
   +<helpers/ui/MomentaryButton.cpp>

variants/wio-tracker-l1/platformio.ini

@@ -16,8 +16,6 @@ build_flags = ${nrf52_base.build_flags}
   -D SX126X_RX_BOOSTED_GAIN=1
   -D PIN_OLED_RESET=-1
   -D GPS_BAUD_RATE=9600
-  -D JP_STRICT
-  -D LORA_CR=5
 build_src_filter = ${nrf52_base.build_src_filter}
   +<WioTrackerL1Board.cpp>
   +<../variants/wio-tracker-l1>