>
> I'd love to see the wireing and sample software for that.

James,

It isn't that big a deal. A tait programmer essentially wires the parallel
port directly to the part except for the HV control. With LVP you can simply
wire the HV control signal directly to RB3. Let me throw out an example:

Wire the following cable on the parallel port:
- pin 5 to RB3 (Vpp control)
- pin 3 to RB6 (Clock)
- pin 2 to RB7 via a 1K resistor (Data Out)
- pin 10 to RB7 (Data In)

The only debatable connection is Vcc control. You can put a switch between
the +5 supply and the Vcc pin on the pic. BTW the resistor is to prevent
pin conflict between the parallel port pin and the data out from RB7.

Now get a copy of Brian Lane's picprg 2.2 which runs under Linux. Configure
the pins listed above and change the 0x08 "Begin Programming" commands
in lowlvl.c to 0x18. Be aware that picprg 2.2 currently compiles under
Linux 2.0.X kernels and requires some modifications to work under 2.2.X
kernels. E-mail me for more details on the process.

picprg should program the part like a champ. If the program loaded is a
bootloader then the cable, picprg 2.2, and everything else associated with
traditional programming becomes unnecessary.

The is the experiment I have my students setting up right now. Should have
results next week. They are using a traditional HV programmer but the
process should be the same for LVP.

> I don't see how a
> bootloader can load something before its has itself been loaded into the
> part. Or am I missing something? Is the bootloader you are referring to a PC
> program?

No. The bootloader is a PIC program. Check out Tony Nixon's ROMZap at
http://www.picnpoke.com/demo/ROMZap.zip in the boot.asm file. Once loaded
into part, that code will subsequently load programs via the serial port.
But a cable as outlines above can be used for the initial loading of the
bootloader into a completely blank part.

But LVP eliminates building a programmer that generates 10-13V Vpp. That
most of the hardware for a Tait Style programmer.

BAJ
>
> ---
> James Newton mailto:jamesnewton@geocities.com 1-619-652-0593
> http://techref.massmind.org NEW! FINALLY A REAL NAME!
> Members can add private/public comments/pages ($0 TANSTAAFL web hosting)
>
>
> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Byron A Jeff
> Sent: Thursday, March 16, 2000 21:21
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: Old programmer to new flash??
> Importance: Low
>
>
> >
> > You have to get the bootstrap loader in the chip somehow right? Requires a
> > minimal traditional programmer.
>
> Well actually it doesn't. Since the chips come with LVP set, it's possible
> to program them simply using a cable, without bothering with programming
> voltages and whatnot. Connect the cable to the part, program it with the
> bootloader, then put it permanently in the target and program via the
> serial port. Never requires a high voltage supply and only a single
> traditional program.
>
> But the traditional Tait type programmer isn't in the equation anymore.
>
> BAJ
> >
> > ---
> > James Newton mailto:jamesnewton@geocities.com 1-619-652-0593
> > http://techref.massmind.org NEW! FINALLY A REAL NAME!
> > Members can add private/public comments/pages ($0 TANSTAAFL web hosting)
> >
> >
> > -----Original Message-----
> > From: pic microcontroller discussion list
> > [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Byron A Jeff
> > Sent: Thursday, March 16, 2000 12:56
> > To: PICLIST@MITVMA.MIT.EDU
> > Subject: Re: Old programmer to new flash??
> >
> >
> > >
> > > Hiy'all!, has anybody on the list successfully managed to program one
> > > of the newer flash parts, for example 16F873 using one of the simple
> type
> > > programmers designed for 16F84 etc.?.
> > >
> > > I notice looking at the 16F873 pinout that RB7 and RB6 are marked in a
> > > similar way to 16F84 ie. RB7/PGD and RB6/PGC  and MCLR is still
> > > MCLR/Vpp, does this mean the 16F873 will program in the old way as used
> by
> > > 16F84  with no major changes?.
> >
> > There's only one real caveat. The actual programming command on the 16F84
> > (0x08)
> > has been changed on the 16F87X parts to mean "erase cell then program".
> This
> > means
> > that instead of the normal 10ms delay, that for the 16F87X part you need a
> > 20ms
> > delay.
> >
> > The other solution is to switch to the equivalent command for the 16F87X
> > part which
> > is 0x18. Then it only requires 10 ms delay again.
> >
> > >
> > > I know it is only a matter of time before there will be a heap of simple
> > > programmer designs for the new flash pics (just as there is now for the
> > > 16F84), the trend on this list seems to be to use the serial port and a
> > > bootstrap loader code block but I guess both programming methods have
> > > there advantages and disadvantages?.
> >
> > I really don't see any big advantage of the traditional programming
> method.
> > It requires a high voltage supply and typically requires the removal of
> > the part from it's intended target.
> >
> > BAJ
> >
>