18F4431 and Melabs USB programmer ?

[AndrewC]

Anyone have unblemished success programming an 18F4431 on a MELABS USB programmer ? Any hints to share ?

I can get 3 out of 5 devices to program, the others just throw programming errors. I've tried adding the infamous capacitor. Melabs are strangely silent when asked for support.

I checked the MC programming notes today and I'm going to check the analog supplies (AVdd and AVss) are connected tonight.

Last other check I threw up searching today was to try programming with MCLR ON ?

Otherwise I guess I'll need to buy a PicKIT 2 ?

Andrew

[Darrel Taylor]

Do you have anything on RB5/PGM?
If it's left floating during programming it can cause problems.

A pull-DOWN resistor will help if it's floating.
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[AndrewC]

Hi Darrel,

I meant to mention that I had tried that as well.
So the analogue supplies are connected, I've tried with MCLRE_ON and _OFF, I've tried with RB5/PGM pulled down to Vss. No joy.

There seems to be a lot of noise floating around the net with people having trouble programming this PIC.

It looks like I might be having to give MC some money

Andrew

[Darrel Taylor]

Have you tried the latest version of meProg?

http://melabs.com/support/progsoft.htm (4.3 with firmware)
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[AndrewC]

Yup, 4.30beta and upgraded the firmware to meup54
The "volts" check in meProg shows Vdd = NA and Vpp = 13.18 when I "READ ACTUAL"

[Darrel Taylor]

I found this in the A2 silicon Errata ...
http://ww1.microchip.com/downloads/e...Doc/80180c.pdf

<img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=3277&stc=1&d=123792998 0" />

Not sure if it only applies to the ICD2 or not. But the USB programmer might have a similar problem if it's an A2 chip.

A3 silicon doesn't seem to have the problem anymore.
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