Keisuke Matsumoto
Application Engineer
Published: March 23, 2020

Renesas launched the RX23E-A, 32-bit MCU, integrating high-precision Analog Front End (AFE) that achieves 30nVrms (Root Mean Square) with the RMS noise characteristics using 24-bit Delta Sigma A/D converter back in 2019. Today, Renesas released the complete RX23E-A Renesas Solution Starter Kit (RSSK) to resolve the challenges faced in accurate evaluation of analog functions in industrial sensor applications. The RSSK is easy-to-use, and beginners without prior analog background can also start evaluation immediately.

The RSSK and its GUI (Graphical User Interface) tool provide the environment for intuitive parameter settings and accurate analog evaluation.

It is my first time using this RSSK and I plan to find out how high the Effective Number of Bit (ENOB), which is one of the RX23E-A's key features, is.
Here, I start the introduction of RSSK for RX23E-A and will show the steps of using this RSSK to conduct evaluation.

We will take the A/D conversion results as the noise signal level to calculate ENOB with the condition to short AIN2 and AIN3 on the PCB. The MCU sample software is pre-programmed on the MCU, so there is no need for MCU coding to start the evaluation. Just install the USB driver, and everything is done for the setup.

As mentioned earlier, the GUI tools make it easy to set the registers of the RX23E-A MCU, but this time, we will use the initial settings of the pre-programmed software. Below are the initial settings.

Press the “Run” bottom at “Waveform” window to take the A/D conversion data. During the conversion, we can see the real-time A/D signal in a waveform, and max/min, average and ENOB values will be shown in the same window.

Press the “Dump” bottom to obtain the values recorded during the conversion easily. Using this function, we took the values and calculated that ENOB is 18.84 [bits].

Now let’s compare the tested ENOB result and value in the RX23E-A user’s manual. Under the same condition, the user’s manual states that ENOB is 18.8 bit, while our calculation based on the RSSK is 18.84 bit. Therefore, we can see the tested result is accurate and very close to the specified value.

It took less than 1-hour for us to obtain the ENOB result. The RSSK indeed enables quick and accurate MCU Analog evaluation. This marks the end of our test evaluation.

Although we evaluated only the effective number of bits of A/D converter, other key features can also be evaluated with this RSSK. This includes signal sensing and temperature conversion of the temperature controller using the RSSK’s packaged thermocouple sensor, RTD on the board, and downloadable application notes. In addition to that, evaluation of the weight scale system is possible using the appropriate sensor prepared by users. Renesas plans to enhance the application notes by including force sensor system and others. 

For more details please visit the link to RX23E-A and RSSK.

Share this news on