Basic able to output via the ACIA 19200 baud?

4 replies [Last post]
Joined: Mar 1 2012
Posts: 9


I have put the EnhancedWoz monitor in EPROM, allowing me to load assembler programs at 19200 baud instead of 2400 baud. It all works very nice, but if I want to load Basic, I have to call the regular Woz monitor first, as Basic wants to interact with the keybord and the Apple I screen.

Has anybody changed the Basic code, allowing Basic to interact with the "fast" RS232 port??
(thus be able to load Basic progams faster, maybe even do some cursor control?)

Best regards,


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Joined: Jun 5 2008
Posts: 383
Re: Basic able to output via the ACIA 19200 baud?

buildable source for the 4 versions of Apple 1 Basic that I'm aware of is available from a blog post I made a while back.

there are three variables associated with Keyboard input and video output. Change the routines that access those and you should be golden.


The question I have is, once you start hacking and improving on the basic Apple 1 design, why not just switch to the Apple II, which was Apple's next step, and had vast improvements in terms of usability.

A big part of the charm of working with the Apple 1, is experiencing how limited personal computing in that time period was. I have seen a few original Apple 1s that appear to have had serial interfaces hacked onto them. However, very few people back in the day, had a way to save or load programs through serial. The exception might be a lucky person that somehow managed to scrounge a teletype with attached paper tape mechanism.

Mike Willegal

Joined: Oct 9 2011
Posts: 1069
Re: Basic able to output via the ACIA 19200 baud?

I agree with Mike, the fun of the Apple 1 or Mimeo is to work within the limits of what you had in 1976/77. This is why I keep doing all these crazy programming things, but really don't do much to modify the hardware. While I may eventually do something simple like hook a one shot up to the clear screen to a memory address so that I programmatically clear the screen, I wouldn't create something that wouldn't have been thought of back then. Another example: Even though I have a 32k SRAM card I built, I don't use it. I just did it to test out some ideas for my 32k DRAM card which would not be out of time for 1977, just expensive back then....

Joined: Mar 1 2012
Posts: 9
Re: Basic able to output via the ACIA 19200 baud?

Hi Mike,

Thanks for the source, I will give it a try!

Mike and Corey, I am a hardware freek and I really like to get more out of the Apple I, just to demonstrate that it was indeed an impressive design at that time.

As for the Apple II, I still have one, with working floppy disk and even the floppies still boot after 25 years!!

As for the Aone, I am currently building an IO card with sound, EPROM (to store the 5 most popular programs (currently containing Mchess, Lunarlander, EWoz ACIA version and Startrack and a text adventure still to put in the EROM). However, it is still completely usable as a standard Apple I (except for the AT-keyboard...).


Joined: Jun 23 2005
Posts: 48
Re: Basic able to output via the ACIA 19200 baud?

Modifying the hardware is part of the experience - that's what you did back then too. Indeed, the Apple 1 manual discusses hardware changes and the machine came with a prototyping area on the circuit board. Smile

I made a ROM that uses a soft switch to switch between fast serial and slow screen/keyboard. Works for Krusader, BASIC and the monitor.