Maarten Hofman wrote:
>I have had no problems doing ICSP programming of a 16F688 with the
>simple JDM Olimex programmer. Of course, when using JDM, make sure you
>have an IBM compliant serial port first

OK -- thanks.  That's certainly a low-cost and generally useful option,
but I'm nervous about using a programmer that tries to tap power from the
serial lines with my laptop.  It has a power-saving serial interface that
produces voltages around +/-5V but won't supply much current and enters a
shutdown mode when it doesn't think anything is happening.

Mark Rages wrote:
>Which firmware revision does your PICkit 1 have?

Version 2.0.2

>The PICkit 1 powers up with Vpp on.   However, you could shut off power,
>connect to your circuit and program / verfify, then disconnect it.

I didn't check the behaviour on power-up, but the PICkit 1 definitely
releases VPP and applies VDD after reading or programming the device
using the PICkit 1 Classic software.  That's reasonable behaviour when
it's being used as a demo board, but not in my case.

>... over on the pickit-devel list at google groups, we have alternative
>software, or you could modify the Microchip host software, which is
>open-source. 

Thanks for the tip.  I didn't realise before that the source code for the
PICkit 1 is openly available.  I've now downloaded AN258/AN258A and taken
a look.  It looks feasible to hack it to do what I want, although there's
the complication that control of VDD and VPP appears to be shared between
the PICkit 1 firmware and the Windows software.

I'll keep this in mind as my backup option.

Olin Lathrop wrote:
>I just checked, and my programmers use the Vpp before Vdd method for the
>16F688.  I think they should do what you want, but haven't verified this
>with a scope.  Information about my programmers is at
>http://www.embedinc.com/products.  I think you want the EasyProg.

Thanks -- I'm going to try that.  Even if it doesn't do the job, it'll be
useful to have another programmer which can handle dsPICs (using ICSP) as
well.  I didn't realise that there was a low-cost programmer out there
that did that -- obviously I haven't been paying enough attention.  :-)

I assume that I'll need to use the non-dsPIC firmware (PRG17) with the
PIC16F688 as per the comment on the EasyProg page that the "alternate"
version is needed for this device.  In any case, I'll burn a couple of
PIC16F648As with versions 16 and 17 because I'm likely to use both at
some stage.

I'll report back if it solves my problem with the PIC16F688 board.

Many thanks.
-- 
Ian Chapman
Chapmip Technology, UK
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