jasea
Junior Member
Posts: 53 
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Post by jasea on Aug 9, 2014 7:53:05 GMT -8
Hi all,
Can you tell me where I can find any documentation the STEM board that runs the Pi-Bot?
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Post by croscwa on Aug 16, 2014 9:50:56 GMT -8
The STEM Board is equivalent to the much-used Arduino Uno board; you should have plenty of hits if you Google "Arduino Uno".
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jasea
Junior Member
Posts: 53
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Post by jasea on Aug 17, 2014 0:11:20 GMT -8
Hi croscwa,
I agree that the STEM board is equivalent and similar to the UNO, but it is not identical, I am interested in what happens when the power switch is changed to 3.3 Volts, does the whole card run at 3.3v or just the I/O pins? If it is the whole card, does it run a a slower speed? Also pins A6 & A7, are they like some Arduino's and are just floating input pins without Pull-Up resistors or are they fully functional analog I/O pins.
There were the questions that came to mind when I was looking at the card, and no doubt other people will have further questions that could be answered by some documentation.
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Post by jhomeyer on Apr 16, 2016 14:26:56 GMT -8
So what does the 3.3v vs. 5v switch do? Thank you.
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jasea
Junior Member
Posts: 53
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Post by jasea on Apr 17, 2016 1:26:34 GMT -8
Hi again,
From my tests I think that it just switches in TTL level converters for the I/O pins. You can test this yourself by connecting a voltmeter to a digital pin, load a program that sets the pin to output and sets it high, note the voltage it should be 5V, switch off the Pi-bot, and then move the switch from 5V to 3.3V and power up the Pi-Bot, your volt meter should now be reading 3.3V. To run the ATMEGA328, the processor, on the Pi-Bot, at 3.3 V would need changes to some of the settings (fuses) within the processor to prevent it powering down due to the lower voltage.
Regards
John
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