So, I'm making progress on my Mimeo 1, and need to wait for parts, so now I'm thinking about the keyboard. I've searched and searched online and right now my mind is a jumble. I just wanted to run this by people here to see if I had things right.
I am mainly interested in adapting an Apple II keyboard for my Mimeo, since I like they way they look, and it will match my Apple II which will be sitting nearby. It seems like remapping the Apple II keyboard to the Mimeo keyboard header is pretty simple, and I've found the documentation to do that. The main questions I have are with implementing RESET, CLEAR SCREEN, and BACKSPACE/RUBOUT. From what I have found, RESET works on the Apple II keyboard when remapped to the Apple 1 header, so it's a non-issue (correct me if this is wrong).
Option 1: Early Apple II keyboard with MM5740/AAE encoder on the keyboard. Mike Willegal found a way to do the backspace by rewiring a key and pressing SHIFT to get the desired result (http://www.willegal.net/blog/?p=3351). No clear instructions seem to be available to do the CLEAR function. I guess since I've got to make a harness to remap the Apple II keyboard header to the Apple 1 pins, I can just rig a momentary pushbutton to short the correct pins directly on the header. Or I could cut traces on the keyboard PCB to use an unused key to make this connection.
Option 2: Later Apple II keyboard with separate encoder board, with a KR3600-type encoder chip. There are clear instructions on Wendell Sander's website for how to modify the "repeat" key to provider CLEAR functionality (http://www.apple1notes.com/old_apple/Notes_files/Using%20Apple%20II%20Keyboard%20for%20Apple%201.pdf). It's not clear to me how to get the BACKSPACE functionality on this type of keyboard. I found IEEE-802 accomplished this by rigging up some logical gates to do it (http://www.applefritter.com/content/how-get-backspace-rubout-working-apple-i-clone-smc-kr3600-keyboard-encoder). I'm not really sure how to do this, but I may be able to work it out since he does go over the theory of this modification.
The MM5740 keyboards seem a bit harder to get and more expensive. I'd feel a bit better about hacking up a less rare piece of hardware. Maybe also I can live without the backspace, since it doesn't seem to be a particularly elegant function anyway (just puts an underscore on screen). I guess there are times it could be useful, but maybe not worth the trouble.
So do I have it basically right? Am I missing any viable options that are out there?