nRF52840: Add process.env.SOFTDEVICE for detecting which softdevice version is installed

Author: gfwilliams

ChangeLog

@@ -14,6 +14,7 @@
             nRF52: Fix gatt.setRSSIHandler on the first active connection
             Added i2cRead/WriteReg for simplified internal I2C code
             Bangle.js2: Support for new Bangles with MMC36X0 magnetometer (Bangle.dbg() now shows info)
+            nRF52840: Add process.env.SOFTDEVICE for detecting which softdevice version is installed
 
      2v27 : nRF5x: Ensure Bluetooth notifications work correctly when two separate connections use the same handle for their characteristics
             nRF5x: Remove handlers from our handlers array when a device is disconnected

src/jswrap_process.c

@@ -122,6 +122,8 @@ Returns an Object containing various pre-defined variables.
 * `APP_RAM_BASE` - On nRF5x boards, this is the RAM required by the Softdevice
   *if it doesn't exactly match what was allocated*. You can use this to update
   `LD_APP_RAM_BASE` in the `BOARD.py` file
+* `SOFTDEVICE` - (on nRF52840) the version of Bluetooth Softdevice that is installed on
+  the device, usually `"6.0.0"` or `"6.1.1"`
 
 For example, to get a list of built-in modules, you can use
 `process.env.MODULES.split(',')`
@@ -160,6 +162,17 @@ JsVar *jswrap_process_env() {
   if (app_ram_base)
     jsvObjectSetChildAndUnLock(obj, "APP_RAM_BASE", jsvNewFromInteger((JsVarInt)app_ram_base));
 #endif
+#ifdef NRF52840
+  // Do a CRC of the 32 bytes from offset 256 (in the softdevice area), eg E.CRC32(E.memoryArea(256,32))
+  const char *softdevice = "unknown";
+  JsVar *sdArea = jswrap_espruino_memoryArea(256,32);
+  uint32_t crc = (uint32_t)jsvGetIntegerAndUnLock(jswrap_espruino_CRC32(sdArea));
+  jsvUnLock(sdArea);
+  // compare with known values
+  if (crc == 3039104175) softdevice = "6.0.0";
+  if (crc == 2754746215) softdevice = "6.1.1";
+  jsvObjectSetChildAndUnLock(obj, "SOFTDEVICE", jsvNewFromString(softdevice));
+#endif
 #endif
   return obj;
 }