Epson HX-20 Question

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Mon Feb 24 17:37:44 2003

> Hi Tony,

You've posted to a large mailing list, not to one person. But I suspect
it's me you're asking for, as I do have a few HX20s, and I have the manuals..

>
> Saw your posts on the net regarding HX-20's. I was wondering if you would
> be able to give me a couple pointers. I picked a hx-20 up a few years ago,
> and am now getting a chance to play with it. I have downloaded and read the
> 3 PDF's on Epson's site. I have not been able to find a copy of the BASIC
> Tutorial.

I'ev never seen a tutorial manual for it. The only BASIC manual I have is
the refernce manual, which assumes you know BASIC.

>
> I have a ROM installed in the _bottom_ of the unit. Not in the expansion
> slot, which is filled with the Cassette Unit.

Yes, there is a spare ROM socket on these machines. IIRC, BASIC fits in 4
ROMs/EPROMs, and there are 5 sockets.

Electrically, this socket is very different from the module that fits in
place of the tape drive. The former is directly mapped into the main CPUs
memory map. The latter is a device accessed bit-serially via I/O ports.
This means (amongst other things) that you can directly run machine code
programs in the ROM in the spare socket on the main CPU board, but you
have to copy rpgorams from ROMs in the ROM cartridge into RAM before you
can run them

>
> Should the ROM be autodetected, or does it have to be loaded?

It depends. I think some ROMs were autodetected, some you had to CALL a
particular address for them to appear on the main menu, others just
contained routines that you could CALL from your BASIC programs.

>
> If loaded, how to I load it?

See above, and panic!

-tony
Received on Mon Feb 24 2003 - 17:37:44 GMT

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