Searching \ for '[PIC] ICSP at 3.3V?' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/microchip/devprogs.htm?key=icsp
Search entire site for: 'ICSP at 3.3V?'.

Exact match. Not showing close matches.
PICList Thread
'[PIC] ICSP at 3.3V?'
2005\08\11@120403 by Harold Hallikainen

face picon face
I'm working on a project using the 18LF6520 running at 3.3V. As I read the
datasheet, we can do ICSP programming at this voltage (with high voltage
Vpp), but it does not appear we can erase the chip with this voltage
(datasheet page 319). Does it look like I'm reading this correctly?

THANKS!

Harold



--
FCC Rules Updated Daily at http://www.hallikainen.com

2005\08\11@122733 by Michael Rigby-Jones

picon face


>-----Original Message-----
>From: spam_OUTpiclist-bouncesTakeThisOuTspammit.edu [.....piclist-bouncesKILLspamspam@spam@mit.edu]
>Sent: 11 August 2005 17:04
>To: Pic List
>Subject: [PIC] ICSP at 3.3V?
>
>
>I'm working on a project using the 18LF6520 running at 3.3V.
>As I read the datasheet, we can do ICSP programming at this
>voltage (with high voltage Vpp), but it does not appear we can
>erase the chip with this voltage (datasheet page 319). Does it
>look like I'm reading this correctly?
>
>THANKS!
>
>Harold


Correct, you can program the whole device at 3.3v, but you cannot perform a bulk erase which means you only get one shot at setting the fuses.  The program/EEPROM memory can be erased for re-programming but it takes longer.

Regards

Mike

=======================================================================
This e-mail is intended for the person it is addressed to only. The
information contained in it may be confidential and/or protected by
law. If you are not the intended recipient of this message, you must
not make any use of this information, or copy or show it to any
person. Please contact us immediately to tell us that you have
received this e-mail, and return the original to us. Any use,
forwarding, printing or copying of this message is strictly prohibited.
No part of this message can be considered a request for goods or
services.
=======================================================================

2005\08\11@122823 by Mike Hord

picon face
> I'm working on a project using the 18LF6520 running at 3.3V. As I read the
> datasheet, we can do ICSP programming at this voltage (with high voltage
> Vpp), but it does not appear we can erase the chip with this voltage
> (datasheet page 319). Does it look like I'm reading this correctly?

I think Microchip needs to put out a publication specifically dealing with
this issue.  It's pretty confusing and we've gone over it a few times
just within the last several months.

Are you looking at parameter D132, and D132A?  If so, take heart.  The
limit is on block and externally timed erasing, NOT erasing in general.

This becomes a limit in some cases, because, for example, Olin's
ProProg performs a block erase first, then programs, which means
(AIUI, from the last discussion) it would want to raise the Vdd above
4.5V to do the block erase, then proceed from there.  If you use an
ICD2, however, it doesn't do a block erase.

What does that mean?  It means either your programmer can't do
a block erase (or you can't use a programmer that does a block
erase) OR your system needs to be able to survive that brief
excursion to 4.5+ V to allow the block erase.  In my case, I went
over the low voltage components I am using, and 5V is well within
their "Absolute Maximum" range, meaning they won't die, even
though they can't be used at that voltage.  Or you can isolate the
power coming to the PIC from the ICSP connector...

Mike H.

2005\08\11@130148 by Harold Hallikainen

face picon face
Thanks for the responses! So, as I read it, I can reprogram the code
flash, but perhaps not the config bits, with an ICD-2 at 3.3V, right?

THANKS

Harold


--
FCC Rules Updated Daily at http://www.hallikainen.com

2005\08\11@131654 by Michael Rigby-Jones

picon face


>-----Original Message-----
>From: piclist-bouncesspamKILLspammit.edu [.....piclist-bouncesKILLspamspam.....mit.edu]
>Sent: 11 August 2005 18:02
>To: Microcontroller discussion list - Public.
>Subject: Re: [PIC] ICSP at 3.3V?
>
>
>Thanks for the responses! So, as I read it, I can reprogram
>the code flash, but perhaps not the config bits, with an ICD-2
>at 3.3V, right?
>
>THANKS
>

You can program the config bits in a blank device, but effectively you can't "reset" them.  As long as you program them correctly the first time this shouldn't be an issue.

Regards

Mike (who's suffered greatly in the past with low voltage PICs and ICSP).

=======================================================================
This e-mail is intended for the person it is addressed to only. The
information contained in it may be confidential and/or protected by
law. If you are not the intended recipient of this message, you must
not make any use of this information, or copy or show it to any
person. Please contact us immediately to tell us that you have
received this e-mail, and return the original to us. Any use,
forwarding, printing or copying of this message is strictly prohibited.
No part of this message can be considered a request for goods or
services.
=======================================================================

2005\08\11@132341 by Bob Axtell

face picon face
Harold Hallikainen wrote:

>Thanks for the responses! So, as I read it, I can reprogram the code
>flash, but perhaps not the config bits, with an ICD-2 at 3.3V, right?
>
>THANKS
>
>Harold
>
>
>  
>
No, the only thing you cannot do is perform a bulk erase.

--Bob

--
Note: To protect our network,
attachments must be sent to
EraseMEattachspam_OUTspamTakeThisOuTengineer.cotse.net .
1-866-263-5745 USA/Canada
http://beam.to/azengineer

2005\08\16@104540 by alan smith

picon face
I did exactly that....did a jumper to power the PIC with 5V  when and IF I needed to do a block erase.

Mike Hord <mike.hordspamspam_OUTgmail.com> wrote:> I'm working on a project using the 18LF6520 running at 3.3V. As I read the
> datasheet, we can do ICSP programming at this voltage (with high voltage
> Vpp), but it does not appear we can erase the chip with this voltage
> (datasheet page 319). Does it look like I'm reading this correctly?

I think Microchip needs to put out a publication specifically dealing with
this issue. It's pretty confusing and we've gone over it a few times
just within the last several months.

Are you looking at parameter D132, and D132A? If so, take heart. The
limit is on block and externally timed erasing, NOT erasing in general.

This becomes a limit in some cases, because, for example, Olin's
ProProg performs a block erase first, then programs, which means
(AIUI, from the last discussion) it would want to raise the Vdd above
4.5V to do the block erase, then proceed from there. If you use an
ICD2, however, it doesn't do a block erase.

What does that mean? It means either your programmer can't do
a block erase (or you can't use a programmer that does a block
erase) OR your system needs to be able to survive that brief
excursion to 4.5+ V to allow the block erase. In my case, I went
over the low voltage components I am using, and 5V is well within
their "Absolute Maximum" range, meaning they won't die, even
though they can't be used at that voltage. Or you can isolate the
power coming to the PIC from the ICSP connector...

Mike H.

More... (looser matching)
- Last day of these posts
- In 2005 , 2006 only
- Today
- New search...