[CC1101] Fixed known binary receive length

src/modules/CC1101/CC1101.cpp

@@ -335,9 +335,10 @@ int16_t CC1101::startReceive() {
 
 int16_t CC1101::readData(uint8_t* data, size_t len) {
   // get packet length
-  size_t length = len;
+  size_t length = getPacketLength();
-  if (len == RADIOLIB_CC1101_MAX_PACKET_LENGTH) {
+  if((len != 0) && (len < length)) {
-    length = getPacketLength(true);
+    // user requested less data than we got, only return what was requested
+    length = len;
   }
 
   // check address filtering

src/modules/CC1101/CC1101.h

@@ -652,7 +652,8 @@ class CC1101: public PhysicalLayer {
 
       \param data Pointer to array to save the received binary data.
 
-      \param len Number of bytes that will be received. Must be known in advance for binary transmissions.
+      \param len Number of bytes that will be read. When set to 0, the packet length will be retreived automatically.
+      When more bytes than received are requested, only the number of bytes requested will be returned.
 
       \returns \ref status_codes
     */