Sniffer with ringbuf, works SOMETIMES

* Sniffer uses phone endpoints for communication and the ringbuffer
    routines the phone communication uses
* Most times the Usart1 interrupt is not triggered, and therefore
    no values are recorded
diff --git a/firmware/src_simtrace/simtrace.h b/firmware/src_simtrace/simtrace.h
index 229207d..9634b0e 100644
--- a/firmware/src_simtrace/simtrace.h
+++ b/firmware/src_simtrace/simtrace.h
@@ -46,6 +46,7 @@
 extern const USBConfigurationDescriptor *configurationDescriptorsArr[];
 
 /*  Helper functions    */
+int check_data_from_phone();
 
 // FIXME: static function definitions
 extern uint32_t _ISO7816_GetChar( uint8_t *pCharToReceive );