On Sun, 11 Feb 2007 01:44:42 +0100, Joachim Wunder
put finger to keyboard and composed:
On Sat, 10 Feb 2007 10:27:49 +1100, Franc Zabkar
wrote:
On Fri, 09 Feb 2007 02:10:40 +0100, Joachim Wunder
put finger to keyboard and composed:
Yes, I am aware of the fact that I would need a PIC programmer and a
new 8748 or 8749 PIC (I´m still not sure which one it really is).
Pretty good question where to still get such a component from, I
know,... is there any equivalent PIC which offers the same pin
assignment and code compatibility of a 8748/8749? I know, even I doubt
that, but I better ask in this group before giving up.
It could also be an 8751, although the location of the crystal would
suggest a 48 or 49. You should be able to narrow down the likely
contenders for the uC by determining which pins are Vcc (40?), Vdd
(26?), Ground (20?), crystal (2 & 3?), reset (is there a resistor and
capacitor at pin 4?).
I just measured: Pin 40 is Vcc, Pin 26 is Vdd, Pin 20 is Ground, Pins
2 & 3 are crystal. At Pin 3 there is a 22 picofarad capacity as well.
Between Pins 4 & 5 is a resistor with 10kOhms.
I think you're right about the uC being an 8748 or 8749. I'd confirm
that the reset pin (4) is not being held low by a shorted reset cap,
especially if it is a tantalum type. BTW, pin 5 is connected to Vcc,
so the 10K resistor is essentially a pullup.
FWIW, I have some 8749 chips in my junk box. I also have a device
programmer that can handle them. If you are lucky, and if the uC has
dead ports but accessible EPROM, and if the security bit (?) has not
been set, then I may be able to copy it for you. In the past I've been
able to recover code from bad ROM versions of Intel uCs and replace
them with the EPROM versions.
Thanks for your very friendly offer. I just recovered my old Eprom
Burner from 1992 yesterday night. It´s a German model from www.elv.de
with a separate ISA card, DOS software and an external adapter which
plugs right into the ISA card with a fat ribbon cable. Unfortunately,
right now I only have the 32 pin textool external adapter which is
capable to mainly handly only EPROMs at sizes up to 2 MByte. Anyway, I
just contacted ELV Germany and asked them whether they still have the
external adapter with 40 pin textool socket. This adapter is
explicitely described to be able to handle 8748/49 µCs in the manual
of the burner. And even the old DOS software is able to handle these
8748/49 µCs. Thus, I will see what ELV will respond. I then may get
back to your friendly offer. 
Thanks a mil.
I have an old (1991?) Sunshine Expro-60 with an ISA controller card in
an old 486 box.
BTW, I'm in Australia.
Oh, well. I always order most of my satellite dish from Australia.
Thus, distance shouldn´t be an issue for me. *g*
That's a big surprise. I would have thought these dishes were cheaper
in Europe where satellite TV is much more widespread.
- Franc Zabkar
Kind regards
Joachim
- Franc Zabkar
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