Booting Mac Plus right from ROM + some games!

[uniserver]

lol can’t you tap into the 3 megs between SCSI and SCC ?  

sorry you give me and inch and i am trying to take a mile 

 Flashing on on the fly… ( in machine ) is super awesome… Wonder if your software could be used with Dougg3′s 2mb and 8mb simms ? lol then people will not need to buy his programmer.

not that dougg3's programmer isn't awesome...   

 

[techknight]

But then there is the chicken and the egg situation. If somehow the write becomes corrupt, then the machine is braindead where an external programmer would be required. 

 

[bigmessowires]

Off Topic: Do you have an easy solution for getting screenshots from the 68k's to the modern web? I was using photoshop 1.0 to convert them to gif, then FTP'ing them over. 

I actually ran the program under Mini vMac in Windows to generate the screenshot.

Yeah, you still need an external EPROM programmer to do the initial programming of the flash chips - you can't just stick blank ROMs in the computer and boot it up. But once the ROM has been programmed once, you can use this Flash Tool to update its contents without removing the chips from your Mac. If you could get a friend to do the initial programming for you, or buy pre-programmed chips, then in theory you wouldn't need an external EPROM programmer at all. But techknight's right about the risk of some unexpected error writing bad data to the code section of the ROM, essentially bricking the Mac until you reprogrammed the flash chips externally.

I looked into it a little, and I don't think it's possible to extend the ROM area beyond 1 MB without multiple hardware and software changes. In theory it's probably doable, but not really worth the effort. 1 MB is a good number. But maybe someday...

 

[olePigeon]

Have you thought about using test clips or even better, killy clips (if you can find them), to make it a non-solderable mod?

 

[lameboyadvance]

There are 28 pin DIP IC 'test clips' like the one listed here, but not only are they $8 each plus postage, but they are likely too high to be usable inside a Mac.

 

[bigmessowires]

bbraun used wires with test clips, check out his photo:

I was never able to get that to work, though. There's very little clearance between the CPU and the SIMMs, and between the CPU and the chassis frame. A couple of times I was able to get clips to stay put long enough to try sliding the logic board back inside the case, but the wires always caught on the chassis and ripped out.

 

[Trash80toHP_Mini]

LOL! Powering up my good IIsi to to test a 12" RGB with a pair of those same clips hooked up to address lines on MDU killed it deader-n-a-doornail! I forgot I had a few PDS Cards stored inside on top of them . . .

OOPSIE!!!!!!!!!!!!!!!!! ;D

I'm still lovin' those clips though. On power-up that IIsi board now does the most amazing VampireVideo ScreenDump!

 

[Cory5412]

Off Topic: Do you have an easy solution for getting screenshots from the 68k's to the modern web? I was using photoshop 1.0 to convert them to gif, then FTP'ing them over.

I have had good luck with a similar approach -- copy the files to my netatalk server and use GraphicConverter on my Mac mini with Mac OS X 10.9 or 10.10 to convert them to PNG files. It works really well, at least with the screenshots system 7 saves.

 

[IPalindromeI]

if you have Photoshop, Photoshop 4 supports PNG and runs on 68k. You could export to GIF as well and use pngcrush on it.

 

[bigmessowires]

OK, the universal ROM adapter for Mac Plus, 512Ke, 512K, and 128K is working! It's a single PCB with two sets of socket footprints, so depending on where you add the sockets it can fit logic boards with different chip spacings. I built two of them, one for the Mac Plus and one for the Mac 512K, and they both work. 128K is untested, since I don't have one, but it should work.

bbraun's ROM disk driver initially had some trouble on the 512K, but I managed to fix that, so now it's smooth sailing.

I also made some improvements to my Flash Tool used for in-system ROM updating, so now it's a little more idiot-proof. Just choose which area of ROM you want to update, select a data file to use, and the tool does the rest. It also validates that the file is the right size for the area of ROM you said you wanted to update, to help reduce the chances of bricking your Mac with a bad update.

Flash Tool currently won't run on a Mac 128K, so while you can use the ROM adapter board on that machine, you can't do in-system updating of the ROM contents on it. That may be solvable… not sure yet.

 

[CC_333]

Wow! The Flasher's interface looks nicer too!

I have a 128k I'd be willing to test the adapter in, if you want to send me a "sample" of it?

This is the neatest thing since Dougg3's Custom ROM SIMM!

c

 

[bigmessowires]

This is the board. Thought I'd posted it earlier, but I guess not:

 

[olePigeon]

You should put the Happy Mac ROM space there, too.

 

[bigmessowires]

Funny you mentioned it. I looked at that, and it's certainly doable, but more complex than I thought. The same Macintosh icon data is shared for sad mac, happy mac, and possibly some others. Then the "face" data that appears on the mac screen is stored separately. So without a pretty big code change, you could turn the happy mac icon into a bug-eyed mac or something, but you couldn't change it into something completely different.

 

[uniserver]

You guys have to admit this is some hard core stuff.  

Now that you guys have control of rom with these different mac's.

Your control of these machines, has increased greatly.

So What would stop you from putting linux on the rom and booting that up? 

 

[bigmessowires]

I have a few of these kits available for sale now, if anybody wants one. http://www.bigmessowires.com/mac-rom-inator/

 

[techknight]

Finally got my floppy emulator today. Yea, i broke down and finally bought one. Especially with the scare of disappearing DB-19s, why not? 

 

[olePigeon]

Can the Plus ROM adapter board also be used for LC ROMs?

 

[bigmessowires]

Nope, but it should be possible to design something similar for the LC.