Setting Up a dual boot rom

[rubber_jonnie]

Found some hn27c4096, it's a Chinese seller, so a gamble, but £12 for 5 is worth the gamble, and they are 85ns too.

If they turn out to be duds I'll try the Aussie seller @JezC suggested.

In the meantime I built an image containing TOS1.04 with the patch showing OS detail, plus the IDE boot patch from Cristian and TOS 2.06. Had a lot of fun and games with Hex editors and settled on HxD, though ended up byteswapped, so have fixed it with Cartman.

The idea is that this will go into my Mega 4 to give both 1.04/2.06 compatibility and the ability to boot from IDE from both ROMs. If I can get this sorted and tested once the erasable ROMs come, then I'll upload an image to the ROMs section.

EDIT: I've just done a file comparison with an original TOS1.04/TOS2.06 image that I know works, and it's looking great, with only some small differences, which are where the TOS1.04 IDE patch has been made.

Looking forward to getting the ROMs so I can get it burned and tested.

[DoG]

The chips kodak80 linked to comes from Shenzhen, China. Only the link was .au (Australia).

[Glorfindeal]

I found these, while the aren’t erasable, at least they aren’t too far away. Should I get the 55ns ones?

https://www.mouser.com/Search/Refine?Keyword=27C4096

Thanks,


Ken

[DoG]

I found these, while the aren’t erasable, at least they aren’t too far away. Should I get the 55ns ones?

https://www.mouser.com/Search/Refine?Keyword=27C4096

Good choice, but as you said, you can only program them once. If you screw up somehow, they are useless.

Little pricey for learning on.

[rubber_jonnie]

The chips kodak80 linked to comes from Shenzhen, China. Only the link was .au (Australia).

TBH we had a power cut here, so I didn't look further than Australia!

[Glorfindeal]

I found these, while the aren’t erasable, at least they aren’t too far away. Should I get the 55ns ones?

https://www.mouser.com/Search/Refine?Keyword=27C4096

Good choice, but as you said, you can only program them once. If you screw up somehow, they are useless.

Little pricey for learning on.

Yeah, but the only erasable ones are from China and I don’t really want to wait a month + to get them.

Ken

[DoG]

...
Yeah, but the only erasable ones are from China and I don’t really want to wait a month + to get them.

Totally valid point. I didn't know you had everything else already.

[Glorfindeal]

...
Yeah, but the only erasable ones are from China and I don’t really want to wait a month + to get them.

Totally valid point. I didn't know you had everything else already.

My GQ-4x4 is due in next week. :)

[rubber_jonnie]

Estimated delivery for my erasable chips is 2-3 weeks, I'll have to manage without in the meantime as no spares anyway. At least they are in the post as of this morning.

[Glorfindeal]

My GQ-4x4 is due in tomorrow. I decided to order 2 erasable EPROMs from china. It should come in around 3-4 weeks. I also ordered 6 OTW ones from Mouser.