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Minerva Rom burning

Posted: Thu Nov 23, 2017 3:08 pm
by Flocke1967
Short question about Minerva Rome: Can you just burn it on an Eprom (256K or 512k - which one is needed?) Or do you need any circuits in addition to the ROM? The ROM file is freely available ...

Thanks in advance for clarifying answers.

Re: Minerva Rom burning

Posted: Thu Nov 23, 2017 5:04 pm
by Pr0f
The Minerva ROM is 48K, but you can download an image that included toolkit II as well, and fits in a 64K Eprom - a 27c512. That should work in either socket in the QL I believe. Otherwise you will need to provide a board and additional logic to decode the bottom 48K space.

Re: Minerva Rom burning

Posted: Thu Nov 23, 2017 11:13 pm
by XorA
Depending on board version you need to change a jumper or dead insect a 74LS00 (or equiv NOT gate) and re-route a couple of pins to use an EPROM. Even for 64k Minerva+TK2

Re: Minerva Rom burning

Posted: Fri Nov 24, 2017 8:34 am
by Flocke1967
Pr0f wrote:The Minerva ROM is 48K, but you can download an image that included toolkit II as well, and fits in a 64K Eprom - a 27c512. That should work in either socket in the QL I believe. Otherwise you will need to provide a board and additional logic to decode the bottom 48K space.


Can you send me the ROM-File?

Re: Minerva Rom burning

Posted: Fri Nov 24, 2017 8:54 am
by Peter
The same question has already been answered for you in the German QL forum. No, the 27C512 does not directly fit without adaptor.
For more details, please read the explanation gives there: http://forum.tlienhard.com/phpBB3/viewt ... f=9&t=2567

Re: Minerva Rom burning

Posted: Fri Nov 24, 2017 9:02 am
by Pr0f
You can download the images from Dilwyn's site :

http://www.dilwyn.me.uk/downloads.html

He has a page for toolkits and for ROM's

On a PC you can extract the zip files and once you have the resulting ROM images you can do the following:

copy /b your_ql_rom_image + your_toolkit_image new_rom_image

burn the new_rom_image file and you are good to go...

I am sure someone did post up on the forum recently a combined Minerva + TK2 image - but I'm scuppered for finding it this morning...

Re: Minerva Rom burning

Posted: Fri Nov 24, 2017 9:37 am
by tofro
Note for a simple merge, you need to make sure the Minerva ROM image is exactly 48k. Most aren't. There is, however, a version of 1.98 on Dilwyn's site that has been amended to comply.

Tobias

Re: Minerva Rom burning

Posted: Fri Nov 24, 2017 9:42 am
by Pr0f
good point - My programmer allows me to load in binary images at any starting address - so I generally use that method if I am 'merging' roms for a larger target device.

Re: Minerva Rom burning

Posted: Fri Nov 24, 2017 11:21 am
by Pr0f
It was so long ago that I did this on the original QL board - I had the issue 5 board and repurposed the LS logic chip that provided some additional address translation around the 2 sockets. From the circuit diagram, the ROMS have OE has a high enable, and the CE pins are tied to the A15 line - I think I remember reading somewhere that the 2 rom chips have different CE logic level, so one is enabled when a15 is low and one when it is high. If I remember rightly, I tied CE (pin 20) on the 64K eprom to ground, and used the invert of the ROMOEH signal to enable ROM output (pin 22) , and I must have messed around with the tracks around pin 1 and pin 20 of the socket to reroute the A15 to pin 1.

Yet another occasion of the 'wouldn't it have been nice if...' Just a few jumper pins would have done it...

Re: Minerva Rom burning

Posted: Fri Nov 24, 2017 12:56 pm
by tofro
Pr0f wrote:Yet another occasion of the 'wouldn't it have been nice if...' Just a few jumper pins would have done it...


Up to issue 5, this jumper pins were there - After the QL ROM story had settled, they removed it in issue 6.

Tobias