Arduino Due & UNI-T UTD2025CL Digital Oscilloscope

Thread Starter

cxshermansg

Joined Sep 1, 2017
10
Hi guys, I have long since been interested in the subject of electrical, electronics engineering. But being a professional IT developer, I only got down to it lately. Due to budget constraints, I did invest in a simple digital storage oscilloscope from UNI-T, I figured it will come in handy when I progress to the stage where I need to solder and prep my own board based upon the prototype.

I also know based on the requirements of my project that I want to use either the Arduino Mega 2560 / Arduino Due. The thing that concerns me right now is that I know that Arduino Due has a much higher clock of 84 MHz, unlike Uno, Mega and the rest that runs at 16 MHz clock speed. Considering that the UNI-T UTD2025CL is stated to be 25Mhz & 250MS/s, I am a little concern about whether or not the Oscilloscope will be good enough. I did a bunch of research online and almost everything I have read so far recommended people to go for something along the range of 100MHz. Is that really necessary when we are working with Arduino related projects?

(I wanted to put this question up because I think it also helps me to understand better in general about what is recommended for folks dabbling in Arduino projects)
 

philba

Joined Aug 17, 2017
959
what will you be measuring? I have an old HP 50 Mhz scope and haven't had a problem. Most of my work is done with teensy 3.2s which are running at 96Mhz. Unless you need to do RF stuff, I think you'll find 25 Mhz to be usable. The one possible issue is if you are building your own processor boards and want to see if the xtal is oscillating. When I do spring for a new scope, I'll probably get a 200 mhz rigol but that's in the future.

A low cost logic analyzer might be a more worthwhile investment, by the way.
 

shteii01

Joined Feb 19, 2010
4,644
Your problem is that 84 MHz is actually cpu speed. You WILL NEVER encounter it because peripherals do not run at that speed, they run at speeds that are much much much slower. For example i2c will run at 400 kHz or maybe even slower so 25 MHz will be plenty to see any i2c signal coming out of Due.

Also. Ask people about Due DAC. Back in 2013 it was still faulty, it would go from 0.5V to 2.7V. See if Arduino people fixed it. It should be from 0V to 3.3V.
 

Thread Starter

cxshermansg

Joined Sep 1, 2017
10
@philba & @shteii01: Thanks guys for the idiot-proof explanation. I really appreciate it. Yes, I will be happy to make another investment in the future (when I absolutely need it). I will go google up about the Logic Analyzer.

Anyway, the reason I've shortlisted Arduino Due for the prototype project is because of its ideal memory size for the program, but ideally, I would like to build a circuitry that is compatible with all other hardware and Arduino mini devices if there is a need to scale or expand in future.

But since we are on the topic of Arduino, mind if I ask another question, it says on paper and documentation that the Arduino Due only supplies up to 3.3V, but I see a 5V pin slot on the board, what is the purpose of that?
 

shteii01

Joined Feb 19, 2010
4,644
@philba & @shteii01: Thanks guys for the idiot-proof explanation. I really appreciate it. Yes, I will be happy to make another investment in the future (when I absolutely need it). I will go google up about the Logic Analyzer.

Anyway, the reason I've shortlisted Arduino Due for the prototype project is because of its ideal memory size for the program, but ideally, I would like to build a circuitry that is compatible with all other hardware and Arduino mini devices if there is a need to scale or expand in future.

But since we are on the topic of Arduino, mind if I ask another question, it says on paper and documentation that the Arduino Due only supplies up to 3.3V, but I see a 5V pin slot on the board, what is the purpose of that?
5V.This pin outputs a regulated 5V from the regulator on the board.
https://store.arduino.cc/usa/arduino-due
Documentation

Some devices can be powered by 5V, but their output is several volts lower (around 3 to 3.5 volts) so you can feed their signals to Due which works on the 3.3V system.
 
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