Mega IIe: First Fully Functional Computer Built Around the Apple Mega-II Chip 

Thanks Clem! Seeing all of your cool projects kept me inspired.

What's insane is that Ample Computers is not capitalizing off of the Apple ][ resurgence. Am convinced they're just not interested in producing product to make money- they want to sell media, etc. Apple has become a sort of watered down software company with a really poor hardware division imho.

Well deserved. There were a couple of times you helped keep me from tearing my hair out. Err.

Thanks Max!

Sigh. You’re right!

That’s cool! I wish I had learned to code on it back in the day. The IIGS is such an underrated machine (outside of the Apple II community.)

@@bald_engineer It was ahead of its time in some ways. The sound capabilities even got Apple in trouble with the Beatles and Apple Music, as the sound chip crossed the line into "music". :-)

Thanks for following up! I don't think Raspberry Pi intended for it to happen, but it's become a fantastic microcontroller for integrating stuff with vintage computing! It's just a shame the inputs are natively 5-volt tolerant!

Right? I love the Floppy Emu. but sometimes, I like booting off of a disk just for the sounds.

I’m up to Master Detective!

Thanks. The project was fun to make ... most of the time. ;)

(that’s a complement)

haha, right? Fortuantely, the battery damage doesn't generally affect the Mega, IWM, or Slotmaker.

I'm going to make an extender board. I just haven't done it yet. I'm also considering a low-rise board to hold an expansion ROM to get Smartport support.

I have no plans to sell the boards. Also, I don’t recommend anyone building the rev 3 board, for obvious reasons.

Check the GitHub repo found here: bit.ly/46vMGJ4 If you don't see what you need, James is usually easy to find over there. . .

Take a nap.

@@bald_engineer lol, sounds about right.

It's an interesting idea, but I don't see the need it would fill. There are already plug-in cards that can provide VGA. There are replacement modern keyboards available. IIe boards aren't known for degrading--there's no battery and no (or almost no) electrolytics on them. If you or someone else wants to go down that path, that would be cool. But it isn't a direction I plan to go.

@@bald_engineer Wish someone can do something more.

Back when I started the case design, I had intended to make the (miniature) keyboard functional. As time went on I dropped that idea. But I had already invested a ton of time into the design.

Not true! You provided polite suggestions when I made dumb mistakes during the design phase of the rev 3 board. :)

They are only available in the IIGS or the incredibly rare Video Overlay Card.

Great! You can sell this as the Apple //GS destroyer. Jobs would be well behind this, if he was still alive. Perhaps someone can check with his frozen head.

@@glynnetolar4423 Being a toxic troll on Facebook isn't enough for you? Now you have to post here and be disgusting?

@@bald_engineer I take it that the IIgs that you got yours from was beyond repair? Taking one from a VOC would be a violation of the sacrosanct!

@@RetroDawn Yes. All of my Mega-IIs (and other ASICs) came from battery-bombed boards. Well, eventually. Early on, I only had one dead board. But later, I got others that I used to restore the "good" boards.

Until I get smartport working, A2Desktop is the only DHR program I've tried. I haven't had time to do any kind of side-by-sides yet.

The IIGS composite video is generated via an encoder which is fed the RGB video, so the composite is just a lesser-quality version of the simulated artifact-colored composite RGB video. So, you were always 100% correct--it is the fault of the RGB video. This Mega IIe should have all of the same issues all of the RGB simulations of Apple IIe video have had over the years (RGB boards from BITD, IIgs, VGA/HDMI cards from more recent past). I've heard the same about the Mega II. Do you have any information as to why Apple never used it in a IIe or IIc (Plus) revision? I always wondered why they didn't, as it should have lowered the cost to build.

@@RetroDawn - The IIGS's composite video differences were actually documented back in 1986 (I was surprised reading a magazine article that showed magnified screen captures) but didn't think much of it at the time. I mean I always used my IIGS with an RGB display, even when running 8-bit software. It wasn't until recent years, when I tried Total Replay on a CRT TV. It's quite a noticeable difference, to the point I've become a purist when playing 8-bit games--not only must they be on a composite CRT display, it must also be a real IIe/IIc to generate those graphics. I think the reason the Mega II wasn't used in the Apple IIe or IIc was it didn't offer a significant cost savings in manufacturing. It's hard to make sense of anything Apple did really, they should have phased out the Apple IIe in 1986. And the IIc as well, or at least turned into a portable IIGS. To this day I still cannot understand the decision that were made surrounding the IIGS. Who's idea was it to ship the machine with only 256K? Or not wire the headphone jack for stereo? Or provide a microphone input? Or use faster CPU's as they became available. The Mega II not being utilized in the 8-bit II line was also a head scratcher.

Interesting idea. However, the technique I'm currently using only works with the Mega-II's output. I've thought about how to make something that would work on the IIGS. However, there are multiple VGA projects already available for both the IIe and IIGS. So, I don't think my concept would add much value.

No plans to create any kind of kit.

I have no plans to sell the boards. And while the design files are available, I do not recommend getting a rev 3 manufactured. It has too many errors, as shown in the video.

@@bald_engineer Will you release a final version bug free, so passionates can build it ? Thank you. Which is the github ? I successfully built the A2VGA (smd version)… this something much more difficult but if we would have the fully working pcb it could be a project to use dead IIgs motherboards using the Mega II chip and IWS…

@@jansaggiori7865 Of course. I created a branch on the Mega IIe github repo called "rev 3b." My intent is to correct mistakes on that version before working on Rev 4. (In Rev 4, I'll probably make significant changes.)

@@bald_engineer Thank you !!!

No emulator looks exactly the composite video, though. I stick to my composite monitors and real hardware. This Mega IIe should look as good as any emulator, though.

@@RetroDawn ooh that's a throw down challenge - I mean, it's not easy, but I think I can do it, and I've seen the tools that make it possible, too

Mid-project I considered SSC support. But valiantly fought against scope creep--especially after I changed my mind about the final version having (at least) one slot. That said, I'll probably at least developed a card for it on the Rev 2 hardware though. I love working with that pile of cards.

If you don't mind feature creep for the final (?) revision, I'd add more RAM, an SD card reader, and maybe HDMI instead of VGA output. When I was a young kid, that would have been my absolute dream machine and if anybody had told me about the modern peripherals that would have blown my mind. Of course, these days, it's just a case of "why does Kirk climb a mountain?" It's a great answer to a novel engineering challenge. Well done!

Would also like a 56000 DSP hackerboard in slot 4 or so!

FWIW. I actually do use the Mega-IIe to write. The single-task nature of the device makes it very easy to focus. Before this project, I did the same with a IIGS. But then I ruined it by getting a network card.

A fully-fuctional //c that fits in the same of the original //c's power brick?

You made a great game! I used it extensively while testing all phases of the rev 2 bring-up. It was especially helpful in validating both the keyboard and joystick interfaces.

@@bald_engineer I released that game on cassette too. if only you had a cassette port...

I had to change the mapping on my keyboard. Switching between the IIe and a USB keyboard was driving me crazy. Regardless, I've always wondered why modern computer keyboard have a caps lock. Why can't we just double-tap shift or something?

Like most computers of the day, the IIGS keyboard controller was its own microprocessor. The VGC is a complex chip. Plus there are many “GLU” chips in the design. I needed two RP2040s because I ran out of IO pins (and time) not processing ability. The keyboard 2040 is only using one core. And the framing core of vga2040 is idle most of time, since it relies on the PIO.

@@bald_engineer Really great work. Inspiring... but your dedication is the most impressive part. Thanks for this video and I'll be looking for more!

I’ve seen a die shot of Mega. It’s an ASIC. I believe IWM and Slotmaker are as well. At the time, Apple added “GLU” to the name of the Gate-Array chips.

It's in the description.

The GLU logic needed to support the Mega-II in a standalone Apple II computer probably negated the cost savings.

All of the Apple II's soft switches work with reads (or peeks). And until the IIe, they also responded to writes. Starting with the IIe, however, some switches changed behavior on a read or write. $C020 is the output toggle for the tape interface. $C030 is the toggle for the speaker. $C05x are various video related things. etc. Look for a list of the "Apple II Soft Switches" for a complete list.

Just to be clear, I'm using the shortcut for PRINT which is a question mark. Also, ?peek(49232) and 49233 essentially does the same thing the GR and TEXT commands in BASIC do.