이안은 뭐하니?

Accelerating my program.

It was a long time one of my wish.

Since I was young time, I like to programming on APPLE II+ (It was my first computer).

And tested functions and even try to make games such as Block out and some shooting games.

But, Only my available language was BASIC and hard to make a sound on BASIC. Just toggle sound was possible.

After some research, I could generate tone and melody by ASM power.

Why APPLE II is slow? Can I make my program run faster?

Some months later, I could find a way... it is BASIC compiler.

It accelerates about 2 times than BASIC speed but still not enough to describe my idea. so have to stop to making arcade game. 

Learning ASM was too much hard. I can't understand why there are just AND,OR,ADD... and MOVE and some branch commands... there is no sound-generating commands...?

Now, I want to make a gift for me.

CPU Accelerator card for my APPLE II.

I'm mostly using APPLE //e so, I try to accelerate my APPLE //e.

After some months of research, I could find a way to design it.

And tested it.. but, It didn't work of course.

Several actual research again...

Finally, I could make it run.
But no screen output and I only could hear a high pitch beep.

What's wrong? and How to solve this issue?

it was my first problem.

Explained about the solving ways.

APPLE II is using video area from base memory and it doesn't read from the I/O BUS.

APPLE II is automatically reading from the main board RAM for video.

Due to this reasons, my first design doesn't show proper screen output.

So, What should I do?

I need video output.

It needed to push Video data to APPLE II and APPLE II output the video.

It required I/O sync to match CPU speed with APPLE II BUS speed anyway.

Also I/O have to send APPLE II properly to have sound(toggle) and keyboard input.

So, now APPLE II has video output and speaker, Keyboard input.

Next time, I will talk about I/O syncing..

Thanks a lot

Ian Kim

Another Revision of PCB was ordered and I'm waiting for it.

In the first design, I used AY3-8912 and good parts going to hard to obtain so change it to AY3-8910 chips.

And now, 6522 part also getting harder to find good one And more failure rates are too many.

So, Tried it to use 65C22 but it doesn't fit well and needs to change circuit redesign.

Designing a new device isn't simple due to old vintage parts need to be provided properly.

it is harder to obtain good working parts.

Due to a lack of good working parts, I also considered replacing it to CPLD but, it isn't good mate for vintage APPLE II so didn't emulate it and now CPLD is just used to replace some of TTL chips.

Once it finished, I could prepare enough amounts of MB4c board.

Please wait more time for it.

Thanks a lot

Ian Kim