A while back, [Jorj] caught wind of a Hackaday post from December. It was a handheld Apple IIe, emulated on an ATMega1284p. An impressive feat, no doubt, but it’s all wrong. This ATapple only has 12k of RAM and only runs at 70% of the correct speed. The ATapple is impressive, but [Jorj] knew he could do better. He set out to create the ultimate portable Apple IIe. By all accounts, he succeeded.
This project and its inspiration have a few things in common. They’re both assembled on perfboard, using tiny tact switches for the keyboard. The display is a standard TFT display easily sourced from eBay, Amazon, or Aliexpress. There’s a speaker for terribad Apple II audio on both, and gigantic 5 1/4″ floppies have been shrunk down to the size of an SD card. That’s where the similarities end.
[Jorj] knew he needed horsepower for this build, so he turned to the most powerful microcontroller development board he had on his workbench: the Teensy 3.6. This is a 180 MHz ARM Cortex M4 running a full-speed Apple IIe emulator. Writing a simple 6502 emulator is straightforward, but Apple IIe emulation also requires an MMU. the complete emulator is available in [Jorj]’s repo, and passes all the tests for 6502 functionality.
The project runs all Apple II software with ease, but we’re really struck by how simple the entire circuit is. Aside from the Teensy, there really isn’t much to this build. It’s an off-the-shelf display, a dead simple keyboard matrix, and a little bit of miscellaneous circuitry. It’s simple enough to be built on a piece of perfboard, and we hope simple enough for someone to clone the circuit and share the PCBs.
> Writing a simple 6502 emulator is straightforward, but Apple IIe emulation also requires an MMU .
What?
Jorj is calling memory mapper of Apple IIe an “MMU”, and it’s ok in the context. But the emulation does not require an MMU. Cortex M4 does not even have one.
I think the article means to say “requires to emulate the Apple IIe MMU / Memory Mapper.
Which probably isn’t that difficult if you are able to write a cycle-accurate 6502 emulator.
If MMU is defined as “emulating a memory mapper”, what computer emulator does not require an MMU?
Great form factor.
I love the word “terribad”. Gonna have to adopt that one. And maybe an emulated Mockingboard sound card…
A proper late model Apple IIe would always have an accelerator, 64K of RAM and a 1MByte RAM expansion card and an internal 40M hard drive that replaces the PSU. It should run at the speed of a 5 to 15MHz 65C02 to be realistic when compared to the real thing.
ARM has the same condition codes on the same bits as 6502 (not a surprise I hope) and 6502 emulators can be really efficient.
“and an internal 40M hard drive that replaces the PSU”
not sure how a HDD can replace a Power Supply Unit, did you mean FDD perhaps ?
He’s referencing the Applied Engineering Vulcan, which was an internal HDD retrofit for the Apple //e that crammed a new power supply and an HDD in the spot where the factory //e power supply goes.
“This is a 180 MHz ARM Cortex M4 running a full-speed Apple IIe emulator.”
Please change the title of this article to “A Full Speed, Portable Apple //e Emulator”, as there is room in this unvierse for an actual Portable Apple //e using a _real_ 6502 processor.
Agreed, but I’d settle for a 6502 implemented in an FPGA!
Wow, looks like Firefox is running !
Skyfox, I think. Wonder if it’s the Mockingboard version so it has better than 1-bit sound?
True, Skyfox !
I’m a little bit biased by the browser war…
Yes, it’s Skyfox! No, it’s just 1-bit sound at the moment. I want to look at a Mockingboard eventually, but I’m starting with all the peripherals that I actually owned :)
Would love to see an Apple IIgs (16-bit) emulator.
…and then he emulated an Epson dot matrix printer and rigged it to print with a portable thermal printer. #myhero !
Please somebody offer this as a kit and take my money!!
I have my original ][ (and a ][+ for backup) but can’t help but wonder each time I start them up if that will be the last time. 40+ years doesn’t exactly improve hardware (computers or meatspace). Plus I would so like to move my fragile old disks to some format a bit more durable.
Wrap this up into something resembling a kit and I am sold.
Package this as a kit or a finished product in a case and sell me 3! Seriously, take my money.
I’m in for 3 also! Please make a kit up!!
How about to start a Kickstarter campaign?
Just wanted to left you guys know, Jenn and I have been building out own version at home, at this time Jorj is working on printing and testing a prototype. We are using the same idea, but our end result will be an apple //+ portable, not an apple //e portable. :)