PIC operating voltage - OT - Solved

[Gabriel]

hello all

On the Microchip website, there are errata files for each pic.
I have a really old datasheet which states that the 16F876A
operates from 4.5 to 5.5V...
the new datasheet states that it operates 2.0 - 5.5V.

I would like to know if the pics I own operate at 2.0 - 5.5V.
(I never needed this until now, and would like to stick to the '876A).

I really do not want to migrate to a different pic...not at my current project stage.

How do I check this? erratas are linked to a device ID/ revision... how can I get it? does 2.0-5.5V only apply to the LF version?

I've searched with no success... google & Microchip.

Thank you and sorry for posting this here.

g
_________________
CCS PCM 5.078 & CCS PCH 5.093

[newguy]

In my experience, the wide operating voltage PICs are the LF's only. However, making the change from an F part to an LF usually only involves changing one or two fuses (the low voltage reset fuses).

The only other thing to watch is your crystal, as the LF parts usually have a maximum crystal frequency that depends on supply voltage, with the lower the supply voltage, the lower the maximum crystal frequency.

Other than that, the code you develop for 5V operation just works at lower supply voltages.

Edit: I just re-read your question. If you're using an LF part at 5V, it functions identically to an F part at the same voltage.

[Gabriel]

hey newguy...

Thanks for your reply...

Maybe I didn't explain myself too well.

I developed my application on a 'F' part.
I do not own any 'LF' parts.
(I live in panama...not too many PIC choices... and U.S. stores are not too fond of international shipping. or international credit cards...)

I want to know if the 'F' parts I own can operate @ 2.0 -5.0V.
From what I understood from the erratas the latest 16F876A parts can operate at the mentioned voltages, basically eliminating the need for the 'LF' variants.

I want to know if the pics I have in my lab are "the latest" parts that can operate at lower voltages...

Thanks again.

g
_________________
CCS PCM 5.078 & CCS PCH 5.093

[newguy]

My best advice would be to just try it. Create a simple program to toggle an output at a certain rate and either observe it on an oscilloscope or (if possible) flash an LED while you vary Vcc.

Also try contacting Microchip directly - they've been responsive to me in the past. Give them the revision of your processors and ask if that particular rev functions at low voltages.

[Gabriel]

thanks newguy
_________________
CCS PCM 5.078 & CCS PCH 5.093

[Ttelmah]

Look again at the newer data sheet. In front of the table of operating voltages, there should be two graphs, giving the supported voltage range for the LF, and F variants, and the frequencies for the voltages. Figures 15.1, and 15.2, on the current sheet. The F876A, is rated to operate down to 4v.

Best Wishes

[bkamen]

there's usually a revision code on the device as well.

That should be referencable against the datasheet or the errata.

If neither of those routes prove useful, put in a ticket to Microchip support via their website asking them, "How do I tell since it's not in the documentation".

That will get you an answer (hopefully) as well as prompt them that it should be documented somewhere.

Don't forget to check their website for that device's "home page" for another PDF that might tell you that ISN'T the datasheet or errata.

Cheers,

-Ben
_________________
Dazed and confused? I don't think so. Just "plain lost" will do. :D

[gpsmikey]

I could not find the equiv. info for the 876A, however, it may still apply - for the 18F14K22, you can find the rev level of the chip using the MPLAB IDE. See if the information on pg 1 of this errata sheet for the 14K22 applies to your chip ...
http://ww1.microchip.com/downloads/en/DeviceDoc/80437D.pdf

mikey
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mikey
-- you can't have too many gadgets or too much disk space !
old engineering saying: 1+1 = 3 for sufficiently large values of 1 or small values of 3