Add support for DEBUG_PRINT using SEGGER RTT

Makefile

@@ -5,6 +5,7 @@ CLOAD_SCRIPT ?= ../crazyflie-clients-python/bin/cfloader
 
 S110 ?= 1     # SoftDevice flashed or not
 BLE  ?= 1     # BLE mode activated or not. If disabled, CRTP mode is active
+DEBUG_PRINT_ON_SEGGER_RTT ?= 0 # debug prints
 
 PLATFORM ?= cf2
 
@@ -85,7 +86,14 @@ OBJS += src/main.o gcc_startup_nrf51.o system_nrf51.o src/uart.o \
         src/syslink.o src/pm.o src/systick.o src/button.o src/swd.o src/ow.o \
         src/ow/owlnk.o src/ow/ownet.o src/ow/owtran.o \
         src/ow/crcutil.o src/ds2431.o src/ds28e05.o src/esb.o src/memory.o \
-		src/platform.o src/platform_$(PLATFORM).o
+		src/platform.o src/platform_$(PLATFORM).o src/debug.o
+
+ifeq ($(strip $(DEBUG_PRINT_ON_SEGGER_RTT)), 1)
+	INCLUDES += -I src/lib/Segger_RTT/RTT
+	OBJS += src/lib/Segger_RTT/RTT/SEGGER_RTT.o src/lib/Segger_RTT/RTT/SEGGER_RTT_printf.o
+	CFLAGS += -DDEBUG_PRINT_ON_SEGGER_RTT
+endif
+
 
 all: $(PROGRAM).elf $(PROGRAM).bin $(PROGRAM).hex
 	$(SIZE) $(PROGRAM).elf

interface/debug.h

@@ -0,0 +1,42 @@
+/*
+ *    ||          ____  _ __
+ * +------+      / __ )(_) /_______________ _____  ___
+ * | 0xBC |     / __  / / __/ ___/ ___/ __ `/_  / / _ \
+ * +------+    / /_/ / / /_/ /__/ /  / /_/ / / /_/  __/
+ *  ||  ||    /_____/_/\__/\___/_/   \__,_/ /___/\___/
+ *
+ * Crazyflie 2.0 NRF Firmware
+ * Copyright (c) 2014, Bitcraze AB, All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3.0 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.
+ */
+
+#ifndef __DEBUG_H__
+#define __DEBUG_H__
+
+#ifdef DEBUG_PRINT_ON_SEGGER_RTT
+  #include "SEGGER_RTT.h"
+#endif
+
+void debugInit(void);
+
+#if defined(DEBUG_PRINT_ON_SEGGER_RTT)
+  #define DEBUG_PRINT(fmt, ...) SEGGER_RTT_printf(0, fmt, ## __VA_ARGS__)
+  #define DEBUG_PRINT_OS(fmt, ...) SEGGER_RTT_printf(0, fmt, ## __VA_ARGS__)
+#else // No debug
+  #define DEBUG_PRINT(fmt, ...)
+  #define DEBUG_PRINT_OS(fmt, ...)
+#endif
+
+#endif //__DEBUG_H__

src/debug.c

@@ -0,0 +1,33 @@
+/*
+ *    ||          ____  _ __
+ * +------+      / __ )(_) /_______________ _____  ___
+ * | 0xBC |     / __  / / __/ ___/ ___/ __ `/_  / / _ \
+ * +------+    / /_/ / / /_/ /__/ /  / /_/ / / /_/  __/
+ *  ||  ||    /_____/_/\__/\___/_/   \__,_/ /___/\___/
+ *
+ * Crazyflie 2.0 NRF Firmware
+ * Copyright (c) 2014, Bitcraze AB, All rights reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3.0 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library.
+ */
+
+#include "debug.h"
+
+void debugInit(void)
+{
+#ifdef DEBUG_PRINT_ON_SEGGER_RTT
+  SEGGER_RTT_Init();
+  SEGGER_RTT_ConfigUpBuffer(0, NULL, NULL, 0, SEGGER_RTT_MODE_NO_BLOCK_TRIM);
+#endif
+}

src/lib/Segger_RTT/License.txt

@@ -0,0 +1,44 @@
+Important - Read carefully:
+
+SEGGER RTT - Real Time Transfer for embedded targets
+
+All rights reserved.
+
+SEGGER strongly recommends to not make any changes
+to or modify the source code of this software in order to stay
+compatible with the RTT protocol and J-Link.
+
+Redistribution and use in source and binary forms, with or
+without modification, are permitted provided that the following
+conditions are met:
+
+o Redistributions of source code must retain the above copyright
+  notice, this list of conditions and the following disclaimer.
+
+o Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the following
+  disclaimer in the documentation and/or other materials provided
+  with the distribution.
+
+o Neither the name of SEGGER Microcontroller GmbH
+  nor the names of its contributors may be used to endorse or
+  promote products derived from this software without specific
+  prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL SEGGER Microcontroller BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
+USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+DAMAGE.
+
+
+(c) 2014 - 2016  SEGGER Microcontroller GmbH
+www.segger.com

src/lib/Segger_RTT/README.txt

@@ -0,0 +1,20 @@
+README.txt for the SEGGER RTT Implementation Pack.
+
+Included files:
+===============
+Root Directory
+  - Examples
+    - Main_RTT_InputEchoApp.c    - Sample application which echoes input on Channel 0.
+    - Main_RTT_MenuApp.c         - Sample application to demonstrate RTT bi-directional functionality.
+    - Main_RTT_PrintfTest.c      - Sample application to test RTT small printf implementation.
+    - Main_RTT_SpeedTestApp.c    - Sample application for measuring RTT performance. embOS needed.
+  - RTT
+    - SEGGER_RTT.c                - The RTT implementation.
+    - SEGGER_RTT.h                - Header for RTT implementation.
+    - SEGGER_RTT_Conf.h           - Pre-processor configuration for the RTT implementation.
+    - SEGGER_RTT_Printf.c         - Simple implementation of printf to write formatted strings via RTT.
+  - Syscalls
+    - RTT_Syscalls_GCC.c          - Low-level syscalls to retarget printf() to RTT with GCC / Newlib.
+    - RTT_Syscalls_IAR.c          - Low-level syscalls to retarget printf() to RTT with IAR compiler.
+    - RTT_Syscalls_KEIL.c         - Low-level syscalls to retarget printf() to RTT with KEIL/uVision compiler.
+    - RTT_Syscalls_SES.c          - Low-level syscalls to retarget printf() to RTT with SEGGER Embedded Studio.