NEC PC-8201A

I first used one of these machines back in the 1980s. Back then i used it as a very portable serial terminal. A few lines of basic allowed it to be stretched to serial conversations for running tests. This was very handy for the embedded computing kit that i was working on at the time.

I bought this machine a few years ago and have used it for much the same purposes and will continue to do so. It’s capable of more though, and with some additional software i thought it might have more of a chance to shine.

This machine is similar to the Tandy Model 100; they share the same Kyocera base design. The Model 100 was very successful and there is a lot of software available for it. The NEC was less successful and has smaller software catalogue. It will run some of the Model 100 software, but there are hardware and firmware differences that limit compatibility. In some cases this can be overcome with some utility programs.

My unit came with 16k of RAM which can be used to store text files and basic programs. These files can be created on the machine but can also be loaded via the serial port using the ROM based terminal program. There is also provision for a floppy disk drive but i don’t have one. Programs can also be saved to and loaded from tape.

The easiest way to demonstrate the capabilities of the machine is to store programs on the machine so that they are read to go. 16k is very limiting though so, practically, more memory is required. An expansion pack is out of reach, but the unit does have provision for another 48k of memory using 8kB memory modules.

These modules are unobtainium, but a kind soul has designed a modern replacement and has made the design available to all:

https://www.pcbway.com/project/shareproject/Model_T_RAM.html

A bought some PCBs and the required components, and set about applying my awful surface mount skills to their construction. Don’t look too closely!

The expansion of bank #1 from 16kB to 32kB was immediate but recognition of the second bank of 32k proved troublesome. It requires a Shift-Bank command followed by Shift-Ctrl without lifting the Shift and with just the right timing. I got there in the end.

The machines were connected with a null model cable. I set up both machines to use 1200 baud with Xon/Xoff flow control. For the PC that looked like:

mode com1: baud=1200 parity=N data=8 stop=1 to=off xon=on odsr=off octs=off dtr=off rts=off idsr=off

On the 8201A it looked like:

stat 5n81xs

The transfer just requires Term followed by Download on the 8201A and then a file copy on the PC. The copied file must be text – binaries won’t work with Term. The file extension given to Download must be DO ie a document.

After receiving a basic program as a document, invoke BASIC and then convert it to tokenised basic by:

load "wumpus.do"
save "wumpus"

The DO file can be deleted afterwards to save space. It does not take long to fill the available space on both banks. It takes less than 10 minutes to fill 64k even at 1200 baud. The storage relies on batteries, so there is every chance that this exercise will be repeated regularly!

Wumpus went the same way as normal.

Starfighter was fun.

Frogger requires graphics characters to loaded for Model 100 compatibility by running chr100. I’m really not sure that the characters are quite right, but the game seemed to play ok.

Fireworks