'Tait's Programmer flavours'
|Hello PIC lovers:
I need to debug my PIC programming gear at once or I'll go
The last I've built is David Tait's Simple 16c84 Programmer
dated 20/06/95. I used a rectangular PCB made by Michael Laidlaw
that uses an external programming power supply and a male 9-pin port.
I've checked all connections and they seem to be OK.
I'm using a cable that's less than 3 feet long.
VPP levels are given by a power supply of 24V DC 1A current.
Computer is a P-166 (ECP parallel port).
I observe the same strange behaviour with programmer
running on at least five different kinds of software
(PicProg2, ProPic, P16Pro, Cybertech, Pix).
The PIC16F84 yields OK on erasure and blank test. Apparently, it
reads the PIC with no problem. Even the leds flash at
the right time. But actual writing is impossible. I always get
errors on Data verify, Program verify and Fuse verify. So data always
remain the same on the PIC, I wasn't able to modify a single cell.
I don't have documentation for this particular programmer
and I'm confused with so many variants. I could device at least
4 variants of Tait's own programmer: Tait 6, Tait 6T, Tait 7, Tait 7T,
and that's just the beginning!
Anybody knows the difference between them?
Can anybody complete this chart for the programmer?
Vdd Vpp Clock DataIn DataOut
P.Port D? D2 D3 D1 D0? Ack?
Inverted Yes? Yes? Yes Yes Yes
Low/High On/Off? ? ? ?
Pix turns the Code Protect flag on when I read the Pic.
If this flag were actually on, can I erase the Pic anyway?
(I just wonder if this flag has something to do with
my burning problem...)(I wouldn't be surprised if I knew I screwd it up!
Believe me, Microchip stuff is really hard. A Motorola HC11 wouldn't have
survived my "extreme enviroment testing conditions" ;-)
P.D.: Sorry that I left multimeter measurements out. I send
my old analog model to the after life and I'm now planning
to buy a digital one next week-end.
P.D.2: I've seen crowded lists before but this one wins my editor's
choice by far! More than a hundred messages a day!
I must be already nuts!
"Hiroshima '45 Tsjernobyl '86 ... Windows '95"
Turn off your ECP parallel port. make it a plain parallel port. Boot from
a DOS floppy disk.
If your programmer works after that, you are on the right path. Every
computer is different.
You can erase an '84 even if the code protect is set. Do not set code
protect on an F84 if you are using software for a C84, otherwise it's fine
to interchange them.
24 volts, eh? I bet your regulators get warm.
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