Altair 8800 Clone Firmware Version 1.92

Announcements about the Altair 8800 Clone including software and hardware updates.

Altair 8800 Clone Firmware Version 1.92

Postby AltairClone » April 17th, 2017, 9:08 pm

Version 1.92 of the Altair Clone firmware is now available on the support page. You may have to hit "refresh" in your browser to see the update.

The primary feature added by version 1.92 is support of the 88-C700 Centronics printer interface. This emulation piggy-backs onto the 2nd serial port in the Altair Clone just like the 88-LPC printer interface that is already present. However, there is one restriction: The serial port device (88-2SIO or 88-SIO) and the Centronics printer device cannot both use interrupts at the same time. This means, for example, when running Timesharing BASIC, you can't use serial port 2 as both a 2SIO user terminal port and the Centronics printer port at the same time. Under normal BASIC however, you could use both ports at the same time since they are not interrupt driven.

Here is the revision history for the update:

  • Add support for the 88-C700 Centronics printer interface. This emulation piggy-backs onto the 2nd serial port in the Altair Clone just like the 88-LPC printer interface that is already present. The Centronics printer interface is selected in BASIC with a "C" response at the printer type prompt. The Centronics interface supports interrupts and is required to use the Altair Accounting package and Time Sharing BASIC as the 88-LPC (Okidata) printer type is not supported by these software packages.

  • Update the configuration monitor to allow selection of the printer type (88-LPC Okidata, 88-C700 Centronics, or neither).

  • An INPUT from either printer data register now returns 0FFh as with the real hardware (the boards do not respond, so the CPU sees 0FFh on the data input bus). Previously, a value other than 0FFh was returned so programs could detect the presence of the port, but since this is not how the real hardware worked, this has been updated.

  • When single stepping from the front panel, previous firmware versions sent OUT data for the 88-LPC through serial port 1 on the Clone instead of serial port 2. This has been fixed.
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Re: Altair 8800 Clone Firmware Version 1.92

Postby Jefferjs » September 19th, 2017, 11:02 am

If I don't care about having a centronics printer, is there any other advantage to updating the firmware?
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Re: Altair 8800 Clone Firmware Version 1.92

Postby AltairClone » September 19th, 2017, 2:28 pm

The only other changes are the last two bullet items. If those don't affect you, then there is no need to update.

Mike
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Re: Altair 8800 Clone Firmware Version 1.92

Postby toml_12953 » September 20th, 2017, 2:19 am

AltairClone wrote:The only other changes are the last two bullet items. If those don't affect you, then there is no need to update.

Mike


Welcome back, Mike! I was afraid I'd have to get by with my new AltairDuino! Don't worry. I still love my Clone!

Why did I get an AltairDuino? I really like having local storage of all the software. I don't need a PC to load or change disks. Also, I can have up to 16 disk drives on line at a time!

What don't I like about it?

Only two serial ports, no cassette port, buggy Bluetooth implementation.

Your name is prominent on the AltairDuino forum. A lot of the software came from your site.

You wouldn't happen to know how to load a .TAP file into the AD, would you?
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Re: Altair 8800 Clone Firmware Version 1.92

Postby AltairClone » September 20th, 2017, 11:34 am

The .TAP files are images of bootable paper tape and cassette software (same image for paper tape or cassette). This means they are loaded through a serial port (or cassette port, which is also a serial port) after entering the appropriate bootstrap loader on the front panel. The bootstrap loader that must be entered on the front panel is unique to the particular version of software you are loading (e.g., 4K BASIC 3.2, 8K BASIC 4.0, etc.) and to which serial device you are using (e.g., SIO at 0/1, 2SIO at 10h/11h, ACR at 6/7). The manual provided by MITS with BASIC provided the appropriate bootstrap loader that had to be entered based on these criteria.

Mike
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