Just curious, anyone come up with an "underscore/rubout" solution for the II plus keyboard?

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Just curious, anyone come up with an "underscore/rubout" solution for the II plus keyboard?

Or are we all perfect typists.

I was wondering if anyone hardwired a key or created a circuit for the Apple II plus so that you can perform a "Rub-Out"?

Thanks,
Corey

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Re: Just curious, anyone come up with an "underscore/rubout" ...

Such a solution would also require a firmware modification, or at minimum, a custom keyboard entry routine at the KSW location.

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Re: Just curious, anyone come up with an "underscore/rubout" ...

I was figuring someone could just tap into the ASCII output with a hardcoded "_" ascii value 1011111 when a keyswitch hardwired is pressed and then have a circuit to strobe the keyboard input on the Apple I to know it was there.

Cheers,
Corey

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Re: Just curious, anyone come up with an "underscore/rubout" ...

Corey986 wrote:
I was figuring someone could just tap into the ASCII output with a hardcoded "_" ascii value 1011111 when a keyswitch hardwired is pressed and then have a circuit to strobe the keyboard input on the Apple I to know it was there.

Cheers,
Corey

I understand your desire to make a backspace/rubout do *something* visual on the Apple I display. Due to the limited video capability and ROM space space, just about anything you do in hardware will confuse something along the way (like having an underscore show up in your input stream). My solution was to implement my own input routine. When a backspace key is pressed, I output a "\" followed by the character just backspaced over, followed by three actual backspace characters. The video section will ignore any control character except CR but if you have a serial port tap on the 6820 (like Vince Briel's product) and your terminal program can set backspace to erase, then you get a visual indication of the erased character on the Apple I and a real backspace on a terminal program. Of course this takes much more code than could fit in the Apple I's ROM space, so it only makes sense on programs you have source to.

Dave...

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Re: Just curious, anyone come up with an "underscore/rubout" ...

I'm actually OK with the _ character indicating the previous character is invalid. I think that is actually what the Apple I does when you have a rubout key. I'm a poor typist and hate to retype a whole line about 3-4 times before I don't mess it up. I actually have Mike Willegal's serial/ps2 adapter for the apple I and could just type the line on a modern computer and send it over, but what fun is that. I want my 1976 experience!!! This is why I've been keyboard fixated lately on getting real parallel keyboard for my Mimeo build (that is another story in itself and a lesson for me in buying vintage computer parts from a stranger).

Cheers,
Corey

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