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   UltrascreenNEC 1.3L (C) 1987-2026 Ultrasoft / Daniel Born / Gary Weber
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60-column by 10-line display driver for the NEC PC-8201/8300 -- Lite edition

Many thanks goes to Daniel Born and Richard Ecklerlin for making this a
reality!

This is the LITE companion to UltrascreenNEC 1.3.  It renders the very same
crisp 60x10 small-font display, but leaves out the full-screen BASIC editor.
In its place is a simple, Model-100-style line editor: you type a line,
Backspace rubs out the character to the left, and ENTER submits it.  And
just as on the original Ultrascreen100, the Left-arrow key doubles as
Backspace -- unlike the NEC's own ROM, where the Left-arrow moves the
cursor instead.  The payoff is size: Lite is roughly 2.9K resident versus
about 4.8K for the full editor, so it hands back nearly 2K more of your RAM.

LOADER.BA - Tokenized BASIC loader/relocator for creating USCNLT.CO from
            scratch. This will create USCNLT.CO at whatever base-address
            you wish.

LOADER.DO - Text-flavor of the Basic loader/relocator

USCNLT.CO - Machine language ready-to-load into your NEC machine, you can
            bypass the loader entirely if you just want the fixed-location
            program which loads at 59355.

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How to install
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There are two ways to install it: an automatic loader that does the work for
you, or a manual load if you'd rather place it yourself.

** The easy way: the loader

The simplest path is UltrascreenNEC Lite's loader, LOADER.BA, which works just
like the original Ultrascreen100 loader on the Model 100. It carries the whole
program inside itself, so LOADER.BA is the only file you need to transfer onto
your PC-8201A or PC-8300.

Load LOADER.BA and run it. It asks:

   Install under address (ENTER=max 62336)

Press ENTER to tuck it up as high as memory allows (recommended), or type an
address if you want it somewhere specific. It relocates UltrascreenNEC Lite to
fit, saves a ready-to-run USCNLT.CO built for that spot, and hands you back
to the main menu. Run that USCNLT.CO and you're straight into 60x10 -- no
CLEAR to work out and no address math to get wrong.

** The manual way

If you'd rather use the pre-built USCNLT.CO (it loads at 59355), transfer it
onto your machine, then from BASIC park high memory at the load address so the
resident code has a safe home:

   CLEAR 0,59355

Now load and run USCNLT.CO the way you'd launch any machine-language program
(for example, selecting it from the main menu).

** Either way

Once it's installed you're in 60x10, and TEXT, TELCOM, and BASIC will all be
60 columns by 10 lines. Type SCREEN 0 any time to go back to the normal 40-
column display, and SCREEN 1 to return to 60.

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Using Ultrascreen Lite
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When you enter BASIC, TEXT and TELCOM, it's just active by default in 60x10
mode.

Because this is the Lite edition, BASIC line entry uses a plain single-line
editor instead of the full-screen editor: Backspace and the Left-arrow key
both rub out the character to the left, and ENTER enters the line. INPUT, LINE
INPUT and direct-mode commands all behave the same familiar, Model-100 way.

You can temporarily disable the 60x10 display from BASIC with this command:

   SCREEN 0

That flips your computer back into 40x8 mode, which persists in all three ROM
programs. BASIC, TEXT and TELCOM will run just as they did before. However,
you will know Ultrascreen is still installed and waiting to be reactivated
anytime because you'll see "Basic  Text  Telcom" listed in mixed case in the
main menu. To reactivate your 60x10 mode, go to BASIC and type this command:

   SCREEN 1

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How to uninstall
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From BASIC:

   CLEAR 0,62336

Answer Y to the "REMOVE Ultrascreen? (Y/N)" prompt and UltrascreenNEC Lite
unhooks itself, resets the screen to 40x8, and hands all of its memory back.
Answer N and it stays put. (Under the hood, any CLEAR that would reach up into
UltrascreenNEC Lite's reserved memory triggers the prompt; 62336 simply hands
back the maximum.)

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Gary Weber
email: gary@web8201.com
www.web8201.com
