Add nRF52 2.4GHz wireless bridge

docs/cli_commands.md

@@ -1117,28 +1117,44 @@ region save
 
 ---
 
-#### View or change the channel used for bridging (ESPNow only)
+#### View or change the channel used for bridging (ESP-NOW and nRF52 only)
 **Usage:**
 - `get bridge.channel`
 - `set bridge.channel <channel>`
 
 **Parameters:**
-- `channel`: Channel number (1-14)
+- `channel`:
+  - ESP-NOW: Wi-Fi channel number (1-14)
+  - nRF52: `1` = 2482 MHz (default), `2` = 2450 MHz, `3` = 2424 MHz. These sit in the gaps between Wi-Fi channels 1/6/11 and the BLE advertising channels
 
 ---
 
-#### Set the ESP-Now secret
+#### Set the ESP-NOW / nRF52 bridge secret
 **Usage:** 
 - `get bridge.secret`
 - `set bridge.secret <secret>`
 
 **Parameters:**
-- `secret`: ESP-NOW bridge secret, up to 15 characters
+- `secret`: bridge secret, up to 15 characters
 
 **Default:** Varies by board
 
 ---
 
+#### View or change the transmit power of the bridge (nRF52 only)
+**Usage:**
+- `get bridge.txpower`
+- `set bridge.txpower <dbm>`
+
+**Parameters:**
+- `dbm`: Transmit power in dBm (-20 to 8 on nRF52840). Values between the radio's supported steps (8, 7, 6, 5, 4, 3, 2, 0, -4, -8, -12, -16, -20) are rounded down, and the reply shows the power actually used.
+
+**Default:** `4`
+
+**Note:** The nRF52 bridge (`bridge.type` = `nrf52-wireless`) uses its own 2.4GHz protocol (1Mbit GFSK) that mimics ESP-NOW. nRF52 and ESP-NOW bridges can't talk to each other, because the nRF52 radio can't transmit or receive Wi-Fi frames. The nRF52 bridge needs a 2.4GHz (BLE) antenna attached and can't run while BLE is active. Starting OTA stops the bridge.
+
+---
+
 #### View the bootloader version (nRF52 only)
 **Usage:** `get bootloader.ver`
 

examples/simple_repeater/MyMesh.cpp

@@ -198,6 +198,8 @@ uint8_t MyMesh::handleAnonClockReq(const mesh::Identity& sender, uint32_t sender
     reply_data[8] |= 0x01;  // is bridge, type UART
 #elif WITH_ESPNOW_BRIDGE
     reply_data[8] |= 0x03;  // is bridge, type ESP-NOW
+#elif WITH_NRF52_WIRELESS_BRIDGE
+    reply_data[8] |= 0x05;  // is bridge, type nRF52 2.4GHz
 #endif
     if (_prefs.disable_fwd) {   // is this repeater currently disabled
       reply_data[8] |= 0x80;  // is disabled
@@ -869,7 +871,7 @@ MyMesh::MyMesh(mesh::MainBoard &board, mesh::Radio &radio, mesh::MillisecondCloc
 #if defined(WITH_RS232_BRIDGE)
       , bridge(&_prefs, WITH_RS232_BRIDGE, _mgr, &rtc)
 #endif
-#if defined(WITH_ESPNOW_BRIDGE)
+#if defined(WITH_ESPNOW_BRIDGE) || defined(WITH_NRF52_WIRELESS_BRIDGE)
       , bridge(&_prefs, _mgr, &rtc)
 #endif
 {
@@ -915,6 +917,7 @@ MyMesh::MyMesh(mesh::MainBoard &board, mesh::Radio &radio, mesh::MillisecondCloc
   _prefs.bridge_pkt_src = 0;    // logTx
   _prefs.bridge_baud = 115200;  // baud rate
   _prefs.bridge_channel = 1;    // channel 1
+  _prefs.bridge_tx_power = 4;   // dBm (nRF52 2.4GHz bridge only)
 
   StrHelper::strncpy(_prefs.bridge_secret, "LVSITANOS", sizeof(_prefs.bridge_secret));
 

examples/simple_repeater/MyMesh.h

@@ -24,6 +24,11 @@
 #define WITH_BRIDGE
 #endif
 
+#ifdef WITH_NRF52_WIRELESS_BRIDGE
+#include "helpers/bridges/NRF52RadioBridge.h"
+#define WITH_BRIDGE
+#endif
+
 #include <helpers/AdvertDataHelpers.h>
 #include <helpers/ArduinoHelpers.h>
 #include <helpers/ClientACL.h>
@@ -114,6 +119,8 @@ class MyMesh : public mesh::Mesh, public CommonCLICallbacks {
   RS232Bridge bridge;
 #elif defined(WITH_ESPNOW_BRIDGE)
   ESPNowBridge bridge;
+#elif defined(WITH_NRF52_WIRELESS_BRIDGE)
+  NRF52RadioBridge bridge;
 #endif
 
   void putNeighbour(const mesh::Identity& id, uint32_t timestamp, float snr);

src/helpers/CommonCLI.cpp

@@ -4,6 +4,9 @@
 #include "AdvertDataHelpers.h"
 #include "TxtDataHelpers.h"
 #include <RTClib.h>
+#ifdef WITH_NRF52_WIRELESS_BRIDGE
+#include "bridges/NRF52RadioBridge.h"
+#endif
 
 #ifndef BRIDGE_MAX_BAUD
 #define BRIDGE_MAX_BAUD 115200
@@ -218,6 +221,9 @@ void CommonCLI::handleCommand(uint32_t sender_timestamp, char* command, char* re
         strcpy(reply, "ERR: clock cannot go backwards");
       }
     } else if (memcmp(command, "start ota", 9) == 0) {
+#ifdef WITH_NRF52_WIRELESS_BRIDGE
+      _callbacks->setBridgeState(false);  // release RADIO before SoftDevice takes it over
+#endif
       if (!_board->startOTAUpdate(_prefs->node_name, reply)) {
         strcpy(reply, "Error");
       }
@@ -613,22 +619,40 @@ void CommonCLI::handleSetCmd(uint32_t sender_timestamp, char* command, char* rep
       sprintf(reply, "Error: baud rate must be between 9600-%d",BRIDGE_MAX_BAUD);
     }
 #endif
-#ifdef WITH_ESPNOW_BRIDGE
+#if defined(WITH_ESPNOW_BRIDGE) || defined(WITH_NRF52_WIRELESS_BRIDGE)
   } else if (memcmp(config, "bridge.channel ", 15) == 0) {
     int ch = atoi(&config[15]);
-    if (ch > 0 && ch < 15) {
+#ifdef WITH_NRF52_WIRELESS_BRIDGE
+    const int max_ch = NRF52RadioBridge::NUM_CHANNELS;
+#else
+    const int max_ch = 14;
+#endif
+    if (ch > 0 && ch <= max_ch) {
       _prefs->bridge_channel = (uint8_t)ch;
       _callbacks->restartBridge();
       savePrefs();
       strcpy(reply, "OK");
     } else {
-      strcpy(reply, "Error: channel must be between 1-14");
+      sprintf(reply, "Error: channel must be between 1-%d", max_ch);
     }
   } else if (memcmp(config, "bridge.secret ", 14) == 0) {
     StrHelper::strncpy(_prefs->bridge_secret, &config[14], sizeof(_prefs->bridge_secret));
     _callbacks->restartBridge();
     savePrefs();
     strcpy(reply, "OK");
+#endif
+#ifdef WITH_NRF52_WIRELESS_BRIDGE
+  } else if (memcmp(config, "bridge.txpower ", 15) == 0) {
+    int dbm = atoi(&config[15]);
+    if (dbm >= NRF52RadioBridge::MIN_TX_POWER && dbm <= NRF52RadioBridge::MAX_TX_POWER) {
+      _prefs->bridge_tx_power = (int8_t)dbm;
+      _callbacks->restartBridge();
+      savePrefs();
+      sprintf(reply, "OK - %d dBm", NRF52RadioBridge::supportedTxPower(_prefs->bridge_tx_power));
+    } else {
+      sprintf(reply, "Error: tx power must be between %d and %d dBm", NRF52RadioBridge::MIN_TX_POWER,
+              NRF52RadioBridge::MAX_TX_POWER);
+    }
 #endif
   } else if (memcmp(config, "adc.multiplier ", 15) == 0) {
     _prefs->adc_multiplier = atof(&config[15]);
@@ -731,6 +755,8 @@ void CommonCLI::handleGetCmd(uint32_t sender_timestamp, char* command, char* rep
             "rs232"
 #elif WITH_ESPNOW_BRIDGE
             "espnow"
+#elif WITH_NRF52_WIRELESS_BRIDGE
+            "nrf52-wireless"
 #else
             "none"
 #endif
@@ -747,11 +773,15 @@ void CommonCLI::handleGetCmd(uint32_t sender_timestamp, char* command, char* rep
   } else if (memcmp(config, "bridge.baud", 11) == 0) {
     sprintf(reply, "> %d", (uint32_t)_prefs->bridge_baud);
 #endif
-#ifdef WITH_ESPNOW_BRIDGE
+#if defined(WITH_ESPNOW_BRIDGE) || defined(WITH_NRF52_WIRELESS_BRIDGE)
   } else if (memcmp(config, "bridge.channel", 14) == 0) {
     sprintf(reply, "> %d", (uint32_t)_prefs->bridge_channel);
   } else if (memcmp(config, "bridge.secret", 13) == 0) {
     sprintf(reply, "> %s", _prefs->bridge_secret);
+#endif
+#ifdef WITH_NRF52_WIRELESS_BRIDGE
+  } else if (memcmp(config, "bridge.txpower", 14) == 0) {
+    sprintf(reply, "> %d", (int)NRF52RadioBridge::supportedTxPower(_prefs->bridge_tx_power));
 #endif
   } else if (memcmp(config, "bootloader.ver", 14) == 0) {
   #ifdef NRF52_PLATFORM

src/helpers/CommonCLI.h

@@ -9,7 +9,7 @@
 #include <helpers/CommonRadioPrefs.h>
 #include <helpers/DynamicConfigSerializer.h>
 
-#if defined(WITH_RS232_BRIDGE) || defined(WITH_ESPNOW_BRIDGE)
+#if defined(WITH_RS232_BRIDGE) || defined(WITH_ESPNOW_BRIDGE) || defined(WITH_NRF52_WIRELESS_BRIDGE)
 #define WITH_BRIDGE
 #endif
 
@@ -56,6 +56,7 @@ class NodePrefs : public ConfigSerializer {
   uint32_t bridge_baud = 0;   // 9600, 19200, 38400, 57600, 115200 (default 115200)
   uint8_t bridge_channel = 0; // 1-14 (ESP-NOW only)
   char bridge_secret[16]; // for XOR encryption of bridge packets (ESP-NOW only)
+  int8_t bridge_tx_power = 0; // dBm (nRF52 2.4GHz bridge only)
   // Power setting
   uint8_t powersaving_enabled = 0; // boolean
   // Gps settings
@@ -146,6 +147,7 @@ class NodePrefs : public ConfigSerializer {
       def("baud", _parent->bridge_baud);   // 9600, 19200, 38400, 57600, 115200 (default 115200)
       def("ch", _parent->bridge_channel); // 1-14 (ESP-NOW only)
       def("secret", _parent->bridge_secret, sizeof(_parent->bridge_secret)); // for XOR encryption of bridge packets (ESP-NOW only)
+      def("txpwr", _parent->bridge_tx_power); // dBm (nRF52 2.4GHz bridge only)
     }
   public:
     BridgePrefs(NodePrefs* parent) : _parent(parent) { }

src/helpers/bridges/BridgeBase.cpp

@@ -31,6 +31,14 @@ bool BridgeBase::validateChecksum(const uint8_t *data, size_t len, uint16_t rece
   return received_checksum == calculated_checksum;
 }
 
+void BridgeBase::xorCrypt(uint8_t *data, size_t len) {
+  size_t keyLen = strnlen(_prefs->bridge_secret, sizeof(_prefs->bridge_secret));
+  if (keyLen == 0) return;
+  for (size_t i = 0; i < len; i++) {
+    data[i] ^= _prefs->bridge_secret[i % keyLen];
+  }
+}
+
 void BridgeBase::handleReceivedPacket(mesh::Packet *packet) {
   // Guard against uninitialized state
   if (_initialized == false) {

src/helpers/bridges/BridgeBase.h

@@ -106,6 +106,19 @@ class BridgeBase : public AbstractBridge {
    */
   bool validateChecksum(const uint8_t *data, size_t len, uint16_t received_checksum);
 
+  /**
+   * @brief Performs XOR encryption/decryption of data using _prefs->bridge_secret
+   *
+   * Used by radio bridges (ESP-NOW, nRF52 2.4GHz) to isolate different mesh networks.
+   * The same operation is used for both encryption and decryption.
+   * While not cryptographically secure, it provides basic network isolation.
+   * An empty secret leaves the data unchanged.
+   *
+   * @param data Pointer to data to encrypt/decrypt
+   * @param len Length of data in bytes
+   */
+  void xorCrypt(uint8_t *data, size_t len);
+
   /**
    * @brief Common packet handling for received packets
    *

src/helpers/bridges/ESPNowBridge.cpp

@@ -93,13 +93,6 @@ void ESPNowBridge::loop() {
   // Nothing to do here - ESP-NOW is callback based
 }
 
-void ESPNowBridge::xorCrypt(uint8_t *data, size_t len) {
-  size_t keyLen = strlen(_prefs->bridge_secret);
-  for (size_t i = 0; i < len; i++) {
-    data[i] ^= _prefs->bridge_secret[i % keyLen];
-  }
-}
-
 void ESPNowBridge::onDataRecv(const uint8_t *mac, const uint8_t *data, int32_t len) {
   // Ignore packets that are too small to contain header + checksum
   if (len < (BRIDGE_MAGIC_SIZE + BRIDGE_CHECKSUM_SIZE)) {

src/helpers/bridges/ESPNowBridge.h

@@ -69,19 +69,6 @@ class ESPNowBridge : public BridgeBase {
   /** Current position in receive buffer */
   size_t _rx_buffer_pos;
 
-  /**
-   * Performs XOR encryption/decryption of data
-   * Used to isolate different mesh networks
-   *
-   * Uses _prefs->bridge_secret as the key in a simple XOR operation.
-   * The same operation is used for both encryption and decryption.
-   * While not cryptographically secure, it provides basic network isolation.
-   *
-   * @param data Pointer to data to encrypt/decrypt
-   * @param len Length of data in bytes
-   */
-  void xorCrypt(uint8_t *data, size_t len);
-
   /**
    * ESP-NOW receive callback
    * Called by ESP-NOW when a packet is received