RoadTest: Enroll to Review the Renesas RX671 MCU Eval Kit
Author: rcsim10
Creation date:
Evaluation Type: Development Boards & Tools
Did you receive all parts the manufacturer stated would be included in the package?: True
What other parts do you consider comparable to this product?: Today most manufacturers license from ARM the 32-bit Cortex M IP to build their MCU, even Renesas has the product line RA that is based on ARM, but for comparing proprietary 32-bit CPU core I found the CURIOSITY PIC32MX470 DEVELOPMENT BOARD: - PIC32MX470F512H 32-bit microcontroller (120MHz CPU, 512KB Flash, 128KB RAM, Full Speed USB, and multiple expansion options) - Two mikroBUS sockets to expand the functionality using MikroElektronika Click adapter boards. - X32 header for audio I/O using Microchip audio daughterboards. I’m sure if we compare with ARM-based 32-bit MCUs we would have a lot of options. Compared with Curiosity PIC32MX470, EK-RX671 has more connection options, like Pmod, Qwiic, and Grove connectors. EK-RX671 also has an SDCard and P3 Audio jack that is not supported by the Curiosity board. Although EK-RX671 has more features, it costs almost double the of the Curiosity board (about $82 vs $44), so the engineers should carefully consider the costs when choosing between them.
What were the biggest problems encountered?: I had some problems using Ubuntu 22.04 as the host machine to compile the demo code using e2 Studio and I also noticed that searches on Google for examples and tutorials for RX671 or even for Renesas in general return very few results, I’ve tried to add a Bosch BM085 sensor but I was not able to properly configure the I2C on the MCU, tried to follow the datasheet and also search for some examples on Google but found just a few that didn’t help at all.
Detailed Review:
About the EK-RX671 Kit
The EK-RX671 development board is based on the new family of microcontrollers from Renesens, the RX671. This new family of microcontrollers is an evolution of the RX65N family and brings a new version of 32-bit CPU (RXv3). It is possible to get a detailed comparison between these two families by accessing the below link, but overall besides the new RXv3 CPU the new RX671 brings more RAM capacity (384Kb vs 256KB from RX65N), on I/O the RX671 brings the new PORTH, possibility to have 2 channels USB and many others improvements.
https://www.renesas.com/us/en/document/apn/differences-between-rx671-group-and-rx65n-group-rev100
The kit comes with a variety of options to connect, like mikroBUS, Qwiic, Grove, Pmod, and Arduino, for me, this is an advantage over other kits like the Curiosity PIC32MX470F512H. Also EK-RX671 kit has some special features as listed below that give engineers a great option to evaluate the RX671 microcontroller:
mikroBUS connector (SPI/UART/I2C) connectors (Uno R3) connectorYou can get the complete description and information from EK-RX671 Kit at https://www.renesas.com/us/en/products/microcontrollers-microprocessors/rx-32-bit-performance-efficiency-mcus/ek-rx671-evaluation-kit-rx671-mcu-group
About the MCU
The EK-RX671 is based on R5F5671EHDFB MCU, as already said it is based on the new RXv3 architecture and belongs to RX671's new family of microcontrollers:
More on the RX MCU series from Renesas: https://www.renesas.com/us/en/products/microcontrollers-microprocessors/rx-32-bit-performance-efficiency-mcus/rx-features
Spec Impressions
I like the specs of this board, considering its price point, I think it brings a lot of features for a fair cost. The special features are something that not all MCU evaluate kits offer, so now let's check how the EK-RX671 goes on the tests.
Documentation
Accessing the link included on the box, I found very good documentation regarding the Kit, especially the user manual has detailed information regarding how to configure the Kit and the special features:
https://www.renesas.com/us/en/document/qsg/ek-rx671-quick-start-guide
https://www.renesas.com/us/en/document/mat/ek-rx671-v1-users-manual
Unboxing
The box size is 23 cm x 10,5 cm x 5 cm, and the board was very well protected with some small boxes inside. The kit contents include the EK-RX671 board itself, a Micro USB device cable (type-A male to micro-B male), and a Micro USB host cable (type-A female to micro-B male):
Out-of-Box Demo
This Kit comes with an out-of-the-box demo, this was very useful to get my first impressions and also to make sure that the board is working as expected.
The demo uses a Serial port to communicate with the PC and show the user a menu with 3 options:
The Kick Start Guide has the instructions to run the demo application, it was very straightforward to make the demo runs:
Alongside the kit information, the demo application also includes a mini-application that changed the frequency and the intensity of the blue LED ( this board has 3 LEDs, Red, Green, and Blue), so using the switches S1 and S2 it was possible to interact with the Blue LED and the information was also displayed at Kit Information as seen below:
Here I changed the intensity for the LED as an example:
The second option from the menu brings to the Quad-SPI Flash test, where is possible to choose the block size for the data that will be written and then read, you can choose 2KB to 64KB with a block size of 2KB:
At the end of the Quad-SPI Flash test, the terminal shows the time to write and read in microseconds:
The third option from the menu shows some links for documentation, this is similar to what is included in the box:
Building and Debugging the Demo
Renesas also offers the source code from the demo, I think this is very interesting as engineers may use this project as a starting point for their prototypes like I did in a very simple way.
https://www.renesas.com/us/en/document/scd/ek-rx671-quick-start-example-project
First, it is needed to install the IDE e2 Studio, it is based on Eclipse IDE and most engineers are familiar with its interface so I do think it was a good choice from Renesas:
My first try was to use a Linux-based PC to run the e2 studio and compile/build the example application, unfortunately, after some days of trying to fix an issue on the compiler I gave up and moved to a Windows-based machine.
On Windows the process to install e2 Studio IDE was very straightforward, it offers the possibility to install the compiler together with IDE installation and also the tools to support the RX family:
After importing the project to the e2 Studio, I was able to successfully compile my version of the demo, still without any changes:
To flash my compiled version of the demo and also enable the debug I must set S4-2 to off to enable the debug port and connect two serial cables on the board:
The debug port enumerate and Renesas USB Development Tools - Renesas E2 Lite on Windows:
Then I just need to debug the application with the option Renesas GDB HArdware Debugging on e2 Studio:
Finally, I was able to load my version of the demo, and of course also able to debug the application:
This window shows up when you change the IDE perspective to C++/Debug, the main options to add or remove breakpoints, watch for variables or even the IO Register are available here:
You can add watch some variables:
Or can add different types of breakpoints ( hardware or software breakpoints):
Changing the Demo
With my own compiled version of the demo application running and the debug working as expected, I moved to change the demo application for a quick test.
The idea here is to add a new option on the terminal menu that would allow the user to turn on/off the Red and Green LEDS ( remember only the Blue LED was being used by the demo application).
As shown below in the results, that was not too difficult to make these changes, although it was facilitated by the ek-rx671 header file that already had the definition of Red and Green LEDs, it was more a matter of changing the file that created the menu, adding some function to change the LEDs status from On to Off and vice-versa:
Conclusion and next steps
Overall I’m very satisfied with the Kit EK-RX671, it offers a very rich set of features with good official documentation and a familiar IDE, but unfortunately, some engineers may have some difficulties finding code samples and examples from the community, at least I had many problems to find examples to use I2C on RX family ( even on the older version of RX family like RX65N). This lack of community support may make the use of this family of microcontrollers very challenging for hobbyists and others coming from other ecosystems like Arduino where there is a plant of contents for them on the web.
I also have some problems trying to use Ubuntu 22.04 on my host PC, the e2 Studio was not able to find the compiler and despite my efforts to fix this, I was not able to compile the demo application on a Linux machine, which may also affects the experience for hobbyists and others.
In short, a very good evaluation board for the RX671 microcontroller, with a rich set of features but in my opinion it is not for hobbyists due to the lack of a good community,
My next step on this board is to add one more option on the terminal menu, this time I will add some temperature, humidity, and barometric pressure sensors.
