> -----Original Message-----
> From: Dan Michaels [SMTP:oricom@USWEST.NET]
> Sent: Friday, January 26, 2001 1:13 AM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      Re: [PIC] Program 16F87X with 16F84 programmer?
>
> Jsalter wrote :
> >Can someone kindly validate (or negate) my tenuous grasp of programming
> the
> >16F87X family?
> >
> >TRUE or FALSE:
> >
> >A "classic" programmer which is made to serially program the 16F84 via
> pins
> >/MCLR, RB6, RB7 (12+ volts, clock, data) may be simply adapted to program
> >any of the 16F87X family micros, by merely routing those lines to the
> >corresponding pins on the bigger chip.  This assumes using programming
> >software that is ready for those chips, e.g. PicAll, IC-Prog, etc.
> >
> >If this is true, then one need only construct a socket adapter to map
> from
> >18 pins to 28 and/or 40 pins.  Right?
> >
>
> Bruce Burdon wrote:
> >I was hoping one of the regulars would answer, but as yet none seem to
> have
> >had the chance (or they emailed you directly - I didn't do this in case
> >lurkers have the same question...).
> >
> >Anyway, I am using hardware designed to program the Pic16f84 on the
> >Pic16f877 - successfully (Microchips design: AN589).
> ............
>
>
> James, Bruce - I am not an expert on programming algorithms,
> but I'll speak what I know, and then maybe one of the experks
> will jump in and beat my answer to pulp ..........
>
> I have an inexpensive parallel-port Tait-like EPIC programmer from
> melabs.com. It only programs one way - applies 13v to /MCLR line
> and strokes RB7/RB6. I've used it to program everything from
> 16C/F84's to 12C672's to 16C62/71/715/73/74/76's, and now doing
> 16F876's.
>
> You select the particular chip in downloader s.w., because the
> configuration words are different in every chip, but the h.w.
> works ok for all of them.
>
> With the 'F87x chips, I just pulled them out of the box and
> put them in the programmer. Apparently, they come from the factory
> not knowing they are any different from the others, and in fact
> so far I have never even used any of the new Flash-ie/debug
> features.
>
Not quite true, they come programmed from the factory to be configured for
low voltage programming mode.  This however does not stop them from being
programmed in the normal manner, the only precaution that should be taken is
to make sure that RB3 (the PGM pin) is grounded during programming, not left
floating.  I personaly have manged to program these parts with RB3 floating,
but this advice was straight from a Microchip FAE not to mention several
piclisters so it's good advice to follow.  Irrespective of the method used
to program the device, the programming voltage is derived internaly from
Vdd, the "programming" voltage applied to MCLR just gates this internal
voltage.  Again this was straight from the FAE.

Regards

Mike

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