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Any idea if Microchip will support 3.3V on MCUs?

 
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Pavel Kolinko



Joined: 15 Mar 2005
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Any idea if Microchip will support 3.3V on MCUs?
PostPosted: Fri Nov 04, 2005 10:23 pm     Reply with quote

Microchip dsPic supports 3.3V.

However I was wondering if anyone knows
whether Microchip has plans to support 3.3V in MCUs.

I looked for 3.3V MCUs on Microchip website, but it doesn't seem like they have any.

Thanks in advance for your help.
Pavel
newguy



Joined: 24 Jun 2004
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PostPosted: Fri Nov 04, 2005 10:29 pm     Reply with quote

The LF processors are low voltage capable. Some are able to run as low as 2.0 V (I think). For example, the 18F452 runs at 4.2 - 5.0 V, while the 18LF452 will run down to something in the neighbourhood of 2 or 3 V. I'm too lazy to look up the exact specs - check microchip's website again.
Pavel Kolinko



Joined: 15 Mar 2005
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Thanks!
PostPosted: Fri Nov 04, 2005 11:19 pm     Reply with quote

Thanks!
I found the LF parts that I need.
MikeValencia



Joined: 04 Aug 2004
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PostPosted: Sat Nov 05, 2005 6:25 am     Reply with quote

Pavel,

Just make sure that you have Brown-Out Reset DISABLED. Otherwise, you'll never get these things to run! I guess the feature is in there because these same 3.3V chips can still run at 5V.
MGP



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PostPosted: Sat Nov 05, 2005 12:29 pm     Reply with quote

You also may have problems with low voltage in-system programming since you can't do a bulk erase at Vdd less than 4.2V. You need to be able to do a bulk erase if you want to change fuse settings, since a bulk erase is the only way to erase the existing fuse settings.
kender



Joined: 09 Aug 2004
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PostPosted: Sat Nov 05, 2005 3:15 pm     Reply with quote

MikeValencia wrote:
Just make sure that you have Brown-Out Reset DISABLED. Otherwise, you'll never get these things to run! I guess the feature is in there because these same 3.3V chips can still run at 5V.

Mike, does it mean that LF chios would need an external microcontroller superviser with a different brownout detect? I've never used LF myself, but I'm curious, because eventually I'll need to re-tool to 3.3V, becasue 5V programmable logic, in turn, is gradually becoming exticnt.
ckielstra



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PostPosted: Sun Nov 06, 2005 5:22 pm     Reply with quote

kender wrote:
MikeValencia wrote:
Just make sure that you have Brown-Out Reset DISABLED. Otherwise, you'll never get these things to run! I guess the feature is in there because these same 3.3V chips can still run at 5V.

Mike, does it mean that LF chios would need an external microcontroller superviser with a different brownout detect? I've never used LF myself, but I'm curious, because eventually I'll need to re-tool to 3.3V, becasue 5V programmable logic, in turn, is gradually becoming exticnt.
It all depends on the PIC model you are using, some models only have a single fixed BOR voltage while other models have multiple preset voltages you can select from. For example the old PIC18LF458 has BOR voltages of 2.0V, 2.7V, 4.2V and 4.5V
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