Thanks Peter, and everyone else who responded.

I have the PIC talking to the DS1620 now, and am able to set hi & low temp
limits, set config and read status, start conversion, and read the
temperature.  A couple of little things, like rotating the data read from
the 1620 at the wrong end of the read routine and an apparent error in the
Dallas data sheet, had me frustrated, but it's looking much better now.

The DS1620 data sheet says & shows CLK being high when RST is raised.  I
found I had to have CLK low when RST was raised or everything went pretty
much to hell.  Go figure.  Maybe it's just me, I don't know, but it works
now.  All I have left to do is write one last routine to translate the 9-bit
temperature value to an ASCII string (+-nnn.n) for display, and I'll be done
with this part.

I found a lot of assembler code for 1620 interfacing, most of it requiring
major surgery to adapt to my environment.  Some was 8051 assembler, in which
I am rapidly losing fluency.  There was some C code, but again none that
would really work for me.  In all cases, though, I was able to glean more
bits of information from someone else's code to either fix mine, or prove to
myself that I was doing that particular part right, so the problem must be
elsewhere.  And I saw one or two bits that I'm pretty sure WON'T work, no
matter what.

The Dallas people were very helpful in answering questions and digging for
code.  What finally provided the most help was some code from phanderson.com
for driving a DS1602 -- different function, same interface.  Microchip
tried, but didn't find anything.

I will be making the results public -- I tried hard to write my code so it
can be very easily modified to work with any hardware configuration, since I
know I'll be using it a lot myself.

Again, thanks to all who helped!

Dale


> I am about to release an Introduction to LCD kit. Kit 134. It shows how to
> connect a 16x2 LCD to a PC and also how to use a DS1620, set HI/LO
> breakpoints, program it, change deg C/F at the push of a key. It
> also shows
> just how to echo keystokes from the keyboard to the LCD.
>
> All C source code is provided, annotated. I am not using a PIC, just a PC.
>
> Get it at the top of
>
> http://kitsrus.com
>
> Kit 134.
>
> regards,
>
> Peter Crowcroft
>                     DIY Electronics (HK) Ltd
>                 PO Box 88458, Sham Shui Po, Hong Kong
> Voice: 852-2720 0255   Fax: 852-2725 0610    Web:  http://kitsrus.com
>    Email: diykit@pacific.net.hk           Email: peter@kitsrus.com
>
> ----------------------------------------------------------------------
>