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Re: Setting Up a dual boot rom

Posted: 10 May 2020 19:40
by 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.

Re: Setting Up a dual boot rom

Posted: 10 May 2020 20:18
by DoG
The chips kodak80 linked to comes from Shenzhen, China. Only the link was .au (Australia).

Re: Setting Up a dual boot rom

Posted: 10 May 2020 22:14
by 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

Re: Setting Up a dual boot rom

Posted: 10 May 2020 22:31
by DoG
Glorfindeal wrote: 10 May 2020 22:14 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.

Re: Setting Up a dual boot rom

Posted: 10 May 2020 22:43
by rubber_jonnie
DoG wrote: 10 May 2020 20:18 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!

Re: Setting Up a dual boot rom

Posted: 10 May 2020 22:51
by Glorfindeal
DoG wrote: 10 May 2020 22:31
Glorfindeal wrote: 10 May 2020 22:14 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

Re: Setting Up a dual boot rom

Posted: 10 May 2020 23:01
by DoG
Glorfindeal wrote: 10 May 2020 22:51...
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.

Re: Setting Up a dual boot rom

Posted: 10 May 2020 23:41
by Glorfindeal
DoG wrote: 10 May 2020 23:01
Glorfindeal wrote: 10 May 2020 22:51...
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. :)

Re: Setting Up a dual boot rom

Posted: 11 May 2020 10:06
by 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.

Re: Setting Up a dual boot rom

Posted: 11 May 2020 12:00
by 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.