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
20MHz PIC on solderless board?
Started by ●February 16, 2005
Reply by ●February 16, 20052005-02-16
"Louis Levin" <loulev@arcotech.com> wrote in message news:s0n511t69brq7sensb21i9omcjd7a81lhn@4ax.com...> 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. > > LouisLouis, I have built many 20Meg PIC Circuits on a solderless breadboard without and problems. There's a picture of one at http://home.iprimus.com.au/mikeandwendy/Board.jpg .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.
Reply by ●February 16, 20052005-02-16
Louis Levin wrote:> 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. > > LouisHi, 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
Reply by ●February 16, 20052005-02-16
Louis Levin wrote:> > 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. > > LouisWhoa! You *do*not* want any bypass caps on the osc. lines! 16F628 can operate with a 20 MHz xtl on a solderless breadboard.
Reply by ●February 16, 20052005-02-16
NewsGroup wrote:> "Louis Levin" <loulev@arcotech.com> wrote in message > news:s0n511t69brq7sensb21i9omcjd7a81lhn@4ax.com... > >>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 > http://home.iprimus.com.au/mikeandwendy/Board.jpg .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. > >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
