On Tue, Mar 02, 2004 at 08:45:02AM -0500, Spehro Pefhany wrote:
> At 06:36 AM 3/2/2004 -0500, you wrote:
> >On Tue, 2 Mar 2004, Tony Nixon wrote:
> >
> >> >And having an on-chip Vpp generator would be nice too. :)
> >> >
> >> >
> >> >
> >> Make 'em all LVP and do away with C series. :-)
> >
> >Unless you're like me, and never use LVP.  I need the extra I/O pin.
> >Bill
>
> Or like me (and certain car companies) and distrust micros that can
> corrupt their own program memory.

Are these (LVP, writing own program memory) not orthogonal? The 16F777 for
example (to my surpise frankly) has LVP but cannot program its own memory.
It was going to become my new 877 (because it has all the nanowatt stuff too)
but that's gone by the wayside. I'm really looking for a 16F877A with nanowatt
in it.

As for LVP Bill is right. And it really sucks because the LVP pin is stuck
right in the middle of an 8 bit port. I know why they did it: Only RB1-RB5
on the 16F74 that the family was modeled after did not have a secondary
function attached and was available on both the 28 and 40 pin parts.

It still sucks nevertheless.

I wish that MChip could figure out a way to program that models Wouters ZPL
bootloader which wiggles the MCLR in a particular pattern. Something simple
like MLCR has to be low for a specific amount of time (like 1ms)  to be
considered a normal reset, but anything faster will actually count the time
inbetween. Since nanowatt chips all have internal osciallators, it should
be real simple to keep count of runtime since reset.

But that's just wishful thinking. I'm on the ZPL train now and am actively
working on a ZPL 16F implementation. Once I get that done I'll simply dedicate
the 384 bytes to the chip for the bootloader, do a high voltage program
(getting that RB4 back on the 16F87X chips), then wiggle MCLR to reprogram
from then on.

BAJ

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