20MHz PIC on solderless board?

Feb 16, 2005 4 Replies

What is the concensus on using PIC's at 20MHz on a solderless prototyping board? In particular, a 16F628A with external crystal.



Purists please note, this is just for proof of concept stuff, not fine tuning a design.



If there are major problems, is there any way around them? Maybe a few extra bypass caps on the rows tied to the oscillator?



Thanks for any advice.



Louis


Louis,

I have built many 20Meg PIC Circuits on a solderless breadboard without and problems.

There's a picture of one at

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.The top board is a 16F628 running at 20MHz with a Max232 to enable it to talk to a PC. As you can see, it doesn't need any additional decoupling.

For the curious out there, the bottom board is the same but using a 16F745 to do the same thing via USB.

HTH

Mike.

Hi,

I do it all the time. I stick the xtal right in the holes going to the pic. Since the PIC has no external rom or ram, it cannot 'crash' do to signal path problems.

Luhan Monat (luhanis 'at' yahoo 'dot' com) "The future is not what it used to be..." http://members.cox.net/berniekm

Whoa! You *do*not* want any bypass caps on the osc. lines!

16F628 can operate with a 20 MHz xtl on a solderless breadboard.

Note the _very tidy_ layout here. The key to making things work on solderless breadboards are to keep the leads short and the layout clean. Personally I'd add more power supply decoupling, but what what's shown obviously works.

Tim Wescott Wescott Design Services http://www.wescottdesign.com

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