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Discussion Groups | Piclist | PIC18F4620 not starting?
A discussion group for the PICMicro microcontroller. Also called the Microchip PIC, this list is dedicated to the use and abuse of this fine, simple, microcontroller. Close to topic posts are welcome, ie. general electronics.
PIC18F4620 not starting? - Nelson Viegas - Jun 15 7:54:17 2008
Hello!
I'm about to use a PIC18F4620@20Mhz for now, but it is unable to
start. The circuit is too simple (just a flashing LED), and if I use a
PIC16F678A, the circuit works fine, bit it for the other PIC it does
not. However, if I touch my MCLR 4K7 resistor with my finger, the chip
(18F4620) works. What am I doing wrong? I've tried diferent
capacitors for the crystal (from 22 to 68pf) but it's a no-go.
Thanks!
Best regards,
Nelson Viegas
------------------------------------
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RE: PIC18F4620 not starting? - Jcullins - Jun 15 9:32:24 2008
Nelson,
Four things you want to do.
1. caps on the crystal, which you have done.
2. .1 cap across power to the pic as close to the pic as possible.
3. select the proper drive for the crystal, you need (HS)
4. pull-up resistor on the reset pin.
JIM
-----Original Message-----
From: p...@yahoogroups.com [mailto:p...@yahoogroups.com] On Behalf Of
Nelson Viegas
Sent: Wednesday, June 11, 2008 9:55 AM
To: p...@yahoogroups.com
Subject: [piclist] PIC18F4620 not starting?
Hello!
I'm about to use a PIC18F4620@20Mhz for now, but it is unable to
start. The circuit is too simple (just a flashing LED), and if I use a
PIC16F678A, the circuit works fine, bit it for the other PIC it does
not. However, if I touch my MCLR 4K7 resistor with my finger, the chip
(18F4620) works. What am I doing wrong? I've tried diferent
capacitors for the crystal (from 22 to 68pf) but it's a no-go.
Thanks!
Best regards,
Nelson Viegas
------------------------------------
to unsubscribe, go to http://www.yahoogroups.com and follow the
instructions
(You need to be a member of piclist -- send a blank email to piclist-subscribe@yahoogroups.com )
Four things you want to do.
1. caps on the crystal, which you have done.
2. .1 cap across power to the pic as close to the pic as possible.
3. select the proper drive for the crystal, you need (HS)
4. pull-up resistor on the reset pin.
JIM
-----Original Message-----
From: p...@yahoogroups.com [mailto:p...@yahoogroups.com] On Behalf Of
Nelson Viegas
Sent: Wednesday, June 11, 2008 9:55 AM
To: p...@yahoogroups.com
Subject: [piclist] PIC18F4620 not starting?
Hello!
I'm about to use a PIC18F4620@20Mhz for now, but it is unable to
start. The circuit is too simple (just a flashing LED), and if I use a
PIC16F678A, the circuit works fine, bit it for the other PIC it does
not. However, if I touch my MCLR 4K7 resistor with my finger, the chip
(18F4620) works. What am I doing wrong? I've tried diferent
capacitors for the crystal (from 22 to 68pf) but it's a no-go.
Thanks!
Best regards,
Nelson Viegas
------------------------------------
to unsubscribe, go to http://www.yahoogroups.com and follow the
instructions
(You need to be a member of piclist -- send a blank email to piclist-subscribe@yahoogroups.com )
Re: PIC18F4620 not starting? - Nelson Viegas - Jun 16 2:47:48 2008
Hi JIM, thanks for your reply.
While searching for an answer, I came across the LVP configuration
bit. I guess this was it. This PIC had been programmed once by a
friend and I guess he used LVP (or didn't know what he was doing). I
checked the code and added the config bit to turn it off. After
another go in programming it using the standard programming method, It
worked! Works fine now. :-D
Thanks for all your help.
Best regards,
Nelson Viegas
2008/6/15 Jcullins:
> Nelson,
> Four things you want to do.
> 1. caps on the crystal, which you have done.
> 2. .1 cap across power to the pic as close to the pic as possible.
> 3. select the proper drive for the crystal, you need (HS)
> 4. pull-up resistor on the reset pin.
> JIM
>
> -----Original Message-----
> From: p...@yahoogroups.com [mailto:p...@yahoogroups.com] On Behalf Of
> Nelson Viegas
> Sent: Wednesday, June 11, 2008 9:55 AM
> To: p...@yahoogroups.com
> Subject: [piclist] PIC18F4620 not starting?
>
> Hello!
>
> I'm about to use a PIC18F4620@20Mhz for now, but it is unable to
> start. The circuit is too simple (just a flashing LED), and if I use a
> PIC16F678A, the circuit works fine, bit it for the other PIC it does
> not. However, if I touch my MCLR 4K7 resistor with my finger, the chip
> (18F4620) works. What am I doing wrong? I've tried diferent
> capacitors for the crystal (from 22 to 68pf) but it's a no-go.
>
> Thanks!
>
> Best regards,
> Nelson Viegas
>
> ------------------------------------
>
> to unsubscribe, go to http://www.yahoogroups.com and follow the
> instructions
(You need to be a member of piclist -- send a blank email to piclist-subscribe@yahoogroups.com )
While searching for an answer, I came across the LVP configuration
bit. I guess this was it. This PIC had been programmed once by a
friend and I guess he used LVP (or didn't know what he was doing). I
checked the code and added the config bit to turn it off. After
another go in programming it using the standard programming method, It
worked! Works fine now. :-D
Thanks for all your help.
Best regards,
Nelson Viegas
2008/6/15 Jcullins
> Nelson,
> Four things you want to do.
> 1. caps on the crystal, which you have done.
> 2. .1 cap across power to the pic as close to the pic as possible.
> 3. select the proper drive for the crystal, you need (HS)
> 4. pull-up resistor on the reset pin.
> JIM
>
> -----Original Message-----
> From: p...@yahoogroups.com [mailto:p...@yahoogroups.com] On Behalf Of
> Nelson Viegas
> Sent: Wednesday, June 11, 2008 9:55 AM
> To: p...@yahoogroups.com
> Subject: [piclist] PIC18F4620 not starting?
>
> Hello!
>
> I'm about to use a PIC18F4620@20Mhz for now, but it is unable to
> start. The circuit is too simple (just a flashing LED), and if I use a
> PIC16F678A, the circuit works fine, bit it for the other PIC it does
> not. However, if I touch my MCLR 4K7 resistor with my finger, the chip
> (18F4620) works. What am I doing wrong? I've tried diferent
> capacitors for the crystal (from 22 to 68pf) but it's a no-go.
>
> Thanks!
>
> Best regards,
> Nelson Viegas
>
> ------------------------------------
>
> to unsubscribe, go to http://www.yahoogroups.com and follow the
> instructions
(You need to be a member of piclist -- send a blank email to piclist-subscribe@yahoogroups.com )