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UnderColor, Volume 1, Number 6, March 8, 1985

  • Title: Defusr
  • Author: Terry Kepner
  • Synopsis: Q&A
  • Page Scans: Link


I have a 32K Extended Basic Color Computer, revision E, and I've heard that the chips are actually 64K but you can only access 32K. When I looked in the October ’83 TCCM, I found the 64K upgrade. When I opened my CoCo I found all the steps except for 7#1O already done. My RAM chips are marked MCM66331AP20. Are they 64K chips? What can I do, if they are 64K, to access most or all of it?

Also, I want to know if my CoCo is compatible with Color Basic 1.2 and Extended Basic 1.1, and where I could get these IC's.

I saw a CPU called a 68B09E. Is it better than the original, and is it compatible?

Alan Salisbury

Lorton, VA

Yes, the chips are 64K. If you want access to the full RAM, finish steps 7-10 in Dennis Kitsz’s article on upgrades. You won't be able to access the upper bank of 32K unless you use a special assembly language driver, such as Dr. Preble’s VDOS, or Spectrum Projects (P.O. Box 21272, Woodhaven, NY, 11421) 64K Utilities.

The other Basics just correct minor errors with the previous versions; other than that they perform exactly alike. If you really want to upgrade your computer to the newer ROMs, you can buy them from Spectrum Projects.

The 68B09E is a faster version of the standard 6809E. Since the upper speed limit of the Color Computer is determined by external chips and the SAM or 6809E, getting the new "B" chip really wouldn't be much help.

You once said to cut out C85 to get the Vitamin E POKE. After you cut it out should you leave it open, or attach a shorting wire?

l have an interference problem with my computer. In my disk manual it says this is because of grounding clips not installed in earlier model Color Computers. The manual states that Radio Shack will install the grounding clips free of charge, but so far two Radio Shacks have refused to work on it because l didn’t purchase it from their stores. Can you tell me how to get the grounding clips and where to install them, without dealing with Radio Shack?

My printer has a feature in it that allows a hex dump of all data coming into it. It is put into this mode by pressing the FF (form feed) button while turning the printer on. Every time I attempt to print in this mode I get normal printer characters, not the hexadecimal numbers I expect. How do I fix this problem?

And finally, l was wondering if it is possible to somehow turn off Disk Basic after a program is loaded from disk, or at least recover the area of memory after the text screen and before the graphics pages.

l have a 32K Disk Basic Color Computer with an E board and an Epson RX-80 printer with an SP-2 interface at 9200 baud from CNR engineering.

Cyrus Dadgar

Lafayette, IN

Leave the removed capacitor open—don't wire it closed or you’ll damage your computer.

Radio Shack stores are supposed to provide service to all owners of their computers, regardless of where they were purchased. I would first ask for the store manager, and if I got no satisfaction, ask him for his district manager so you can file a complaint. In any case, the grounding clips are available from Tandy National Parts, 900 E. Northside Drive, Fort Worth, TX 76102, 817-870-5662. Mastercharge and Visa are accepted and each order includes a $1.50 handling charge. The instructions are included (the clips are installed on either side of the ROM cartridge connector on the Color Computer circuit board).

It sounds like you have a printer problem, not a computer problem.

To disable Disk Basic: POKE298,0: POKE303,0. This won’t give you more RAM but you can now use the area between the video display and the graphics pages for other purposes. (It also disables the PCLEAR command).

We are subscribers to the RCA Computer-Oriented Telex Service and are currently using Nelson’s Super Color Terminal 2.0 (C) tape version in our 64K TRS-80 Color Computer. Unfortunately, this program does not give us a printed copy of what we are sending, and we were wondering if you could suggest a program on tape which would have this additional feature.

Hans W. Koch

Hans W. Koch Co.

Hanover, PA

That depends on what you need: do you want only hardcopy of what you transmit? Or do you want hardcopy of everything received and sent?

In the first case all you need is a printer capable of operating at the RS—232C parameters used for telecommunication (the R/S printers are all set to 600 baud, two stop bits, and no parity checking, instead of the 300 baud, one stop bit, and even parity typically used for BBS work), and a 4-pin Y cable (one end plugs into the Color Computer, the other two ends can be plugged into two different devices).

If you have these two items, plug one end of the Y into your printer cable, the other to your modem. By turning on your printer (and setting its parameters to match the program) everything you send out from Super Color Terminal will be picked up and printed by the printer.

Another choice is the Radio Shack Deluxe RS-232C ROMpak, which doesn’t hog the normal RS-232 port and echoes received data out that line to your printer.

Otherwise you have to get a hardware printer-port device and software that will echo everything to that port for printing. Ultra Term + (Double Density Software, 920 Baldwin Street, Denton, TX, 76205, $55.95 disk), with the PBJ (PO. Box 813, N. Bergen, NJ, 07047) 80-column board ($139.95) and Parallel Printer Port ROMpak, will do the job, but the total combination is expensive.

Can you or any of your readers tell me how compatible the Tano Dragon (64K) is with the TRS-80 Color Computer? As far as l can see, Basic and the memory map are the same. Plug pin-outs are different and the Dragon has a built-in parallel port and video monitor output, but the plugs are easy to fix. What I'm really wondering about is the compatibility of some of the peripherals advertised.

Also, where can I find a list of the command and function tokens (or their addresses in memory) and after l get them, is there any way except typing out the words to access them? Without rewiring the board, that is.

Billy R. Pogue

Thatcher, AZ

The Basics are identical. As long as you stay with Basic programs, you'll have no trouble. The only source for the information about the tokens and such is the Tano Corporation. Write to them with your questions, as they do have the technical manuals available and will sell them if you need a copy or two.

The command and function tokens are only available through machine code programming. Trying to use them from Basic (except for the Disk ROM hooks) will just lock up the computer.

The peripherals should all work exactly the same, since the expansion port of the Tano is identical to the Expansion port of the Color Computer. If you aren’t sure about a product, contact the company that makes the peripheral and see if they have tried to match their product with the Tano Dragon.

The only problem you’ll have will be with software that directly addresses the RS-232 line looking for the printer, and the sound, keyboard, and video addresses. These are different from the Color Computer. Again, the manuals explaining the differences are available from Tano.

Good luck.

I recently purchased "CoIor Computer Programming" which you recommended in the July 1984 issue of The Color Computer Magazine. You said the book would be good for getting started in assembly language, which I would like to learn more about. Unfortunately, it has left me with a lot of questions. Do you have to buy EDTASM+ to run the programs listed in the book, and if so, where can you get EDTASM+ for a good price? If not, how do you run the programs?


Waldoboro, ME

EDTASM+ isn’t required, but some type of assembly language editor/assembler is. EDTASM+ is sold by Radio Shack and is the cheapest one available. It’s sold as either a ROMpak or on a disk. The disk version is more powerful.

A better all-round editor/assembler is available from Cer-Comp (5566 Ricochet Ave., Las Vegas, NV. 89110), but it costs more.

l have recently purchased a TRS-80 16K with Extended Basic that I would like to interface with a

Canon AP300 electronic typewriter. This would be a serial-to-serial connection. Do you know anyone who would make the interface cable at a modest cost, other than Canon, as the Canon cable is relatively high ($400 in Canada)?

Tom Hunter

Beaver Lodge, Alta. Canada

Something is wrong there. The serial-to-serial cable shouldn’t cost more than $50 at the most, if both machines are using the RS-232 standard. I think the box Canon sells converts parallel output from a computer to serial data acceptable to the Canon printer.

The cable from the Color Computer is easy to make: just get a DB-25 connector (male or female) that fits the Canon, and the Radio Shack Color Computer RS-232 4-pin DIN cable. Cut one end off the cable and solder the four wires as follows: Ignore TRS-80 pin 1, TRS-80 pin 2 to DB25 pin 20, TRS-80 pin 3 to DB25 pin 1, and TRS-80 pin 4 to DB25 pin 3. Tie DB25 pins 4, 5, 6, and 8 together.

That should do the job.

Along with my 32K Color Computer (revision E board), I also own a TRS-80 LP VII dot-matrix printer, and the TRS-80 Modem I. I use the Deluxe RS-232 Program Pak to operate my modem. I enjoy the features of the modem software package, one which enables me to print out any received information. I have one problem with this. The computer receives the information faster than my printer can print it. The result is that the buffer loses information while trying to keep up with the computer. The result—a print-out with a lot of words and lines missing. I am thinking of buying a serial-to-parallel interface for my printer, but I'm not sure that this will end my problem. Please tell me if there is any cure for this type of problem.

Also, where can I get a durable, standard Color Computer keyboard, with function keys, and a reasonably good manual explaining how to operate the function keys, all at a great price?

Todd Phelps

Effingham, IL

Simply switching to parallel won’t solve the problem. The printer is still the problem (data comes in the RS-232 line at 300 baud and is sent to the printer at 600 baud, but the printer prints at only 30 characters per second). To cure the problem you need a

faster printer, or a printer-spooler. The printer-spooler would store the data as it comes in and send it to the printer only when the printer is ready.

At the moment those are your only choices. Sorry.

Which of the replacement keyboards is best is a subjective decision. If you want to use special function keys, the software must be "told" they exist. In other words, just because a keyboard has function keys doesn’t mean the software knows how to use them.