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Topic: Using TinyShield with Uno (Read 869 times) previous topic - next topic

STDummy

Dec 19, 2012, 07:19 pm Last Edit: Dec 19, 2012, 07:21 pm by STDummy Reason: 1
Hi guys

I've been programming a bunch of ATTiny85 processors recently and got fed up continually reconfiguring my breadboard each time so decided to buy one of these:
http://www.flytron.com/open-source-hardwares/162-tinyshield-all-in-one-avr-programmer-shield-for-arduino.html
I haven't got it to try it out yet, but I couldn't help noticing that on its schematic it has a 100R resistor to hold the Uno reset pin high, but I've been using a 10uF capacitor from reset to ground.

Can I just use the shield as is or do I still need that cap do you think?  In other words does the Uno reset pin need to be held high or low?
Unfortunately, whilst this thread http://arduino.cc/forum/index.php?topic=86922.0 asks the same question of the designer, it didn't get answered.




If you learn by your mistakes then I am the model pupil

retrolefty

Quote
Can I just use the shield as is or do I still need that cap do you think?  In other words does the Uno reset pin need to be held high or low?


If your using this shield you should not use the that cap for your arduino board. They both (the resistor and cap) perform the function just by different means, so use one or the other but not both. But as this shield has the resistor soldered in place you only choice is to not use the cap.

Lefty

STDummy

Cheers Lefty, thats just what I wanted to hear!  I suspected that was the case but to have it confirmed makes me very happy.
I wonder why the tutorial for using the Uno as an Arduino ISP uses the capacitor rather than the resistor?
Many thanks!
If you learn by your mistakes then I am the model pupil

retrolefty


Cheers Lefty, thats just what I wanted to hear!  I suspected that was the case but to have it confirmed makes me very happy.
I wonder why the tutorial for using the Uno as an Arduino ISP uses the capacitor rather than the resistor?
Many thanks!


Probably because a 10ufd cap is a easier to find then a 100 ohm resistor. But as I said either method can work.

Lefty

STDummy

Yeah, thats true I suppose  :)

I was going to make myself a shield to program the ATTiny85s but it was just as inexpensive to buy this one at less than $20.  Must admit, I'd probably have used the cap!
If you learn by your mistakes then I am the model pupil

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