|
Science Forum Index » Electronics - Basics Forum » pic problem
Page 1 of 1
|
| Author |
Message |
| xxx |
 Posted: Sat Feb 03, 2007 10:16 pm |
|
|
|
Guest
|
noob qusetion.
ive programmed a 16f84 and 16f628a to flash an led. they both flash in
the programmer/experimentor.when i actually build the circuits on a
bread board they dont work.
any ideas whythis could be so. |
|
|
| Back to top |
|
| Randy Day |
| Posted: Sat Feb 03, 2007 10:58 pm |
|
|
|
Guest
|
xxx wrote:
Quote: noob qusetion.
ive programmed a 16f84 and 16f628a to flash an led. they both flash in
the programmer/experimentor.when i actually build the circuits on a
bread board they dont work.
any ideas whythis could be so.
I'm assuming you've checked the power
connections, and the LED isn't wired
backwards; did you connect to the wrong
port pin? Are any pins shorting?
Does the pic work when you put it back in
the programmer? That will tell you if you
blew the pic. |
|
|
| Back to top |
|
| Bob Eld |
| Posted: Sun Feb 04, 2007 5:23 pm |
|
|
|
Guest
|
"xxx" <echarala@bigpond.net.au> wrote in message
news:1170555408.969283.287390@h3g2000cwc.googlegroups.com...
Quote: noob qusetion.
ive programmed a 16f84 and 16f628a to flash an led. they both flash in
the programmer/experimentor.when i actually build the circuits on a
bread board they dont work.
any ideas whythis could be so.
Assuming that all of the connections are proper you problem may be that the
MCLR pin does not stay low before the power gets to full voltage. Be sure to
have at least 10K on this lead to Vcc. An added cap, .1uf to gnd may also be
helpful. Be sure that the power comes up fast. Slowly rising power may cause
confusion with the MCLR voltage. There is a spec. on this. |
|
|
| Back to top |
|
| Guest |
| Posted: Tue Feb 06, 2007 9:07 am |
|
|
|
|
On 3 Feb 2007 18:16:49 -0800, "xxx" <echarala@bigpond.net.au> wrote:
Quote: noob qusetion.
ive programmed a 16f84 and 16f628a to flash an led. they both flash in
the programmer/experimentor.when i actually build the circuits on a
bread board they dont work.
any ideas whythis could be so.
do you have a power-on reset circuit for your pic? They can be funny
about that - had the same thing with 84s myself which was poor POR |
|
|
| Back to top |
|
| Anthony Fremont |
| Posted: Tue Feb 06, 2007 9:22 am |
|
|
|
Guest
|
xxx wrote:
Quote: noob qusetion.
ive programmed a 16f84 and 16f628a to flash an led. they both flash in
the programmer/experimentor.when i actually build the circuits on a
bread board they dont work.
any ideas whythis could be so.
How long are your power leads? Long wires make inductance which results in
slow power rise times. PICs are kinda funny about the rise time of the
power, they want to see the voltage climb fairly quickly. |
|
|
| Back to top |
|
| |
