Interacting with the IWM directly

[Thom Cherryhomes]

The Mac FujiNet needs to be able to interact with the IWM directly, so that we can send our own messages to handle control and networking functions.

Is it safe to twiddle the IWM registers directly? Long term will most likely be a new DRVR, but I'm trying to get us bootstrapped.

I know I am WAY off the map, but hopefully somebody can throw a lifeline.

-Thom

 

[Arbee]

You probably need to disable the built-in .Sony driver somehow to make it 100% safe to directly twiddle IWM/SWIM registers. It's possible that you could just do it when the .Sony driver isn't (and put it back how you found it), but I don't know how reliable that would be. The only real hang up for FujiNet is that as far as I'm aware you can't do IWM bus protocols like the Hard Disk 20 or the Apple II's SmartPort on SWIM2 or SWIM3, so that puts a hard cap on what machines will work. (SWIM1 contains a full IWM cell so when it's switched into IWM mode it should work 100%).

Oh, and you'll want to get the IWM/SWIM address from the low memory global since it does move around a bit.

 

[Thom Cherryhomes]

Yeah. I know there's a hard limit as to what hardware will be able to support this, but we're trying anyway.

Next few weeks are going to be very interesting seeing how many different ways I can abuse the IWM...

 

[eschaton]

Why not use externally clocked serial?

 

[Thom Cherryhomes]

Why not use externally clocked serial?

because one of the main features is literally to boot and load software over the Internet.
we also wanted to utilize the floppy port's faster access speeds.

This device makes sense, the more resource constrained a machine is, so it will give a 128k Mac, features that otherwise would not be possible.