Minerva Mk2 Remake

[t0nyt]

Hi Peter,

Personally, as I have my name down for a QIMSI when available, I’d be very happy to have one with a RTC.

But I appreciate that without other interest it’s not going to be viable for you

Many thanks

[aalea]

Have I2C pins and support for read and write will be a good thing.
As a first step, I think is not necesary to have the RTC or support for it in ROM, if you add the minimum instructions to manage I2C from basic, later is possible to add a program on boot file that read the RTC and update the QL clock, and there is very cheap i2c RTC board in AliExpress and Amazon (less than 1£) that you can connect to the qimsi, PCF8593, DS1302 and others...
I only say this for your consideration if this is less work to you or easy to implement.

[t0nyt]

Ah yes, that's the thread I was remembering - thank you!

I see now that the zip archive I uploaded only included the original plus a more readable version of Tony's original EQN file.

I've since found my updated version 'v1.10' - attached here.

This version uses Pin 6 (which I chose to rename to 'UprROMEn') and, after cutting the track connecting Pin 6 to Vcc and wiring a simple switch to it, connecting Pin 6 either to either Vcc or Gnd, you can select whether or not the 64Kb EPROM is enabled during accesses to the upper 16Kb/ROM area.

The cleverness is all Tony/QView's and not mine - I just tweaked it a bit...

Is this the GAL I should use so I can disable the upper 16KB please? Rather than the one on Github? (I'd like to make sure QIMSI will still work)

And if so, how do I convert the EQN file into a JED file please?

Does anyone have a picture of this switch mod in place please?

Many thanks
Tony

[martyn_hill]

Hi t0nyt!

I'm not sure which version appears on the GitHub I'm afraid, but by default, the upper 16KB of the ROM memory space is mapped -out- in the Minerva MK2 carrier board, thus allowing other devices to use the ext ROM slot. Therefore, if you leave the standard pin connections in place (pin 6 tied to Vcc) and use the original JED file (non switched), then you'll be safe to use it alongside anything that also uses the 16KB external ROM slot, such as the brilliant QIMSI.

If you use instead the modified EQN that I uploaded to the forum as per that post you quoted, then simply attach a DPST switch connecting pin-6 between Vcc or Gnd (enable onboard 16KB or else allow ext. ROM slot, respectively.)

Compiling the EQN back to a JED file is straightforward using the EQN2JED.exe DOS binary that comes as part of the OpalJr DOS package. Can't recall where I downloaded it, but likely as not it's still online somewhere

In any case, I'll find my copy of the equivalent JED and upload it here shortly.

[EDIT - JED now attached.]

Good luck.

[t0nyt]

Many thanks Martyn

I had wrongly assumed the 16kb was mapped in, but the more I think about it the less sense that would make

I don’t see any need to map in the 16kb so will avoid the mod then. Though if I make up more than 1 board I may give it a try

Many thanks

[t0nyt]

I assume there's no technical reason why I can't use Minerva 1.98 (rather than the newer A1 version) on this board, since it's a remake of an old board please?

Asking in case the the 1.98a1 on the minerva remake GitHub has been modified in anyway. Heads off to download and do a byte comparison...

Many thanks

[XorA]

I assume there's no technical reason why I can't use Minerva 1.98 (rather than the newer A1 version) on this board, since it's a remake of an old board please?

Asking in case the the 1.98a1 on the minerva remake GitHub has been modified in anyway. Heads off to download and do a byte comparison...

Many thanks

1.98a1 has some bugs fixed. But if you don't care about the bugs use any version you wish!

[XorA]

https://www.kilgus.net/ql/minerva/

For details

[t0nyt]

I assume there's no technical reason why I can't use Minerva 1.98 (rather than the newer A1 version) on this board, since it's a remake of an old board please?

Asking in case the the 1.98a1 on the minerva remake GitHub has been modified in anyway. Heads off to download and do a byte comparison...

Many thanks

1.98a1 has some bugs fixed. But if you don't care about the bugs use any version you wish!

Ok, thanks

1.98a1 won't run Vroom (and 1.98 does) so 1.98 is my preferred Minerva version

Many thanks

[t0nyt]

Sorry, another question

The PCB layout on GitHub seems to have I2c pin 1 marked as the pin furthest from the crystal, but the Minerva I2c manual says pin 1 is nearest the crystal

Could anyone confirm which is correct for the remake please?

Want to make sure I get my harness the correct way around as I’ll be using 15 pin d-subs (rather than the 9 pin the manual suggests) to keep it compatible with my existing bbc I2c stuff

Many thanks