In the last article I showed you how to install the Percepio Tracealyzer into your PSoC FreeRTOS project using snapshot mode.   This mode is very convenient as it has little CPU impact and does not require a communication interface.  But your trace it is limited in record time by how much RAM you are willing to dedicate to the trace.   For me, this was not very much because I am using a small PSoC with limited RAM.  In this article I am going to show you how to use the Segger JLink RTT library to support the Tracealyzer RTT Streamport.  With this library built in, the RTOS events will be sent in real-time to the Pecepio Tracealyzer for analysis.

JLink Real Time Transfer (RTT) Library

The engineers at Segger had a great idea.  Really great.  Given that they had direct access to the memory of the ARM M0 (for programming) that could be read and written without CPU intervention via the Coresite Debug Access Port, wouldn’t it be nice if there was a simple way to “send” and “receive” data without using another communication peripheral on the device.

So they built the Segger Real Time Transfer (RTT) Library which works with their JLink.  Here is a picture which I got from their website.

Segger JLink RTT

I will talk more about this library in a future article.

Installing the Percepio Tracealyzer RTT Streamport

I decided to use a copy of the blinking led project (called 1-BlinkingLED) to start the new project.  To copy the project just use CTRL-C and CTRL-V then rename the project to 1-BlinkingLED_RTT.

To make all of this work you need to add the streaming include files for the Tracealyzer RTT Streamport by right clicking “Add–>Exiting Item…”

PSoC Creator Add Existing

Then selecting “TraceRecorder–>streamports–>Jlink_RTT_include”

PSoC Creator Add Existing

Next you need to update the include path for the project by right clicking on the project and selecting “Build Settings”

PSoC Creator Change Build Settings

Then add the path to the TraceRecorder\streamports\JLink_RTT\include

PSoC Creator Update Include Path for Tracelyzer RTT Streamport

Next, add the .c files for the RTT library.

PSoC Creator - Add Tracelyzer RTT Streamport Library

Now that all of the required files are part of your project, you need to modify the “trcConfig.h” to switch to the stream recording mode (line 102).

 * Configuration Macro: TRC_CFG_RECORDER_MODE
 * Specify what recording mode to use. Snapshot means that the data is saved in
 * an internal RAM buffer, for later upload. Streaming means that the data is
 * transferred continuously to the host PC. 
 * For more information, see
 * and the Tracealyzer User Manual.
 * Values:

My PSoC 4M only has 16K of SRAM.  So, I reduce the memory footprint of the streaming buffer by changing it to 1000 byte from 5000 bytes in trcStreamingPort.h.

 * Configuration Macro: TRC_CFG_RTT_BUFFER_SIZE_UP
 * Defines the size of the "up" RTT buffer (target -> host) to use for writing
 * the trace data, for RTT buffer 1 or higher.
 * This setting is ignored for RTT buffer 0, which can't be reconfigured
 * in runtime and therefore hard-coded to use the defines in SEGGER_RTT_Conf.h.
 * Default buffer size for Tracealyzer is 5000 bytes. 
 * If you have a stand-alone J-Link probe, the can be decreased to around 1 KB.
 * But integrated J-Link OB interfaces are slower and needs about 5-10 KB, 
 * depending on the amount of data produced.

Run Tracealyzer

After the project is updated for the Tracealyzer RTT Streamport, I can program it into my CY8CKIT-044 development kit.  The next step is to start the Tracealyzer.  If you have previously run the program it will use your previous J-Link settings.  If you have not run it before then you need to setup the J-Link Settings

Percepio Tracelyzer

I am using a CY8CKIT-044 which has a CY8C4247xxx PSoC 4200M MCU onboard.

Configure JLink for Tracelyzer RTT Streamport

I use the default settings for the Segger RTT.

Tracelyzer RTT Streamport Stream Trace Settings

Once things are setup you can “Connect to Target System…”

Percepio Tracelyzer

Then click “Start Recording”

Percepio Tracelyzer

As you are recording the Tracealyzer shows the CPU usage.  In this case it is very close to 0% as all the program does is blink the LED and then sleep for 500ms.

Percepio Tracelyzer Recording

After I stop recording I can look at the trace.   The first thing to notice in this trace is that I can look at quite a bit more data.  In this case I recorded for about 22 seconds.

Percepio Tracelyzer

In the next article I am planning on doing a Streamport based on the PSoC UART which means I will not need to use a JLink.

As always you can find all of these projects on the IotExpert GitHub site or

Article Description
Percepio Tracealyzer & PSoC An Introduction to Percepio Tracealyzer on the Cypress PSoC
Percepio Tracealyzer RTT Streamport - PSoC4200M Make the JLINK RTT Library work with Tracealyzer
Percepio Tracealyzer PSoC UART Streamport Creating a UART Streamport
Percepio Tracealyzer - Analyzing the PSoC Tracealyzer Streamport Figure out what is broken in the UART Streamport
Percepio Tracealyzer - Using PSoC DMA to Fix the UART Streamport Implementing PSoC DMA to improve the CPU Utilization
Percepio Tracealyzer - Running on PSoC6 Porting the Percepio Tracealyzer to PSoC6

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