9815 peripherals - rom images ?

[artag]

I need an IO module for my 9815S and don't have any hope of getting a real one, so I'm planning to build one.
But I need the ROM image - are there any available ? Or do you have one you can read ?
Looking for images of any of 98133A (BCD), 98134A (general I/O), or 98135A (HPIB).

Or, of course, if you have one of those interfaces available, that would be great !

[John Ioannidis]

I have all three interfaces, but not readily accessible, so I can't check them right now. Are the roms socketed? As confident as I am with my reworking skills, these are practically irreplaceable items, so the less I mess with them, the better.

[artag]

Thanks for responding - I'm sorry that I've only just seen this.

I don't believe the ROMs are socketed (they're not in my 98132A plotter interface) and in fact are probably ceramic roms on a narrow pin frame which is unlikely to be compatible with common eprom programmers and would, I suggest, be very risky to remove however skilled you are.

However, I'm working on a way to read them less invasively. I don't have much time available for this so this won't be fast, but there are a couple of ways it could be done safely. Would be delighted to discuss.

-adrian

[vassilisprevelakis]

(12-18-2022 05:33 PM)artag Wrote:  However, I'm working on a way to read them less invasively. I don't have much time available for this so this won't be fast, but there are a couple of ways it could be done safely. Would be delighted to discuss.

-adrian

Hi Adrian,

Since the 9815 must be able to read these ROMs over the bus, my guess is that a simple device like an Arduino connected to the bus (pretending to be the 9815) should be able to read the ROM.

Best Regards

Vassilis

[artag]

(12-19-2022 03:35 PM)vassilisprevelakis Wrote:  Since the 9815 must be able to read these ROMs over the bus, my guess is that a simple device like an Arduino connected to the bus (pretending to be the 9815) should be able to read the ROM.

Yes, that was my first thought, too. The original roms do need some weird voltages but it's not impossible and of course the cartridge itself contains the pin drivers.

Another option is to catch the data from the bus with a USB logic analyzer. I haven't checked but it's possible the initialization runs through the entire rom space to do a checksum.

Finally, it might be possible to create a new cartridge using a modern rom to provide a debug monitor capable of doing the usual microprocessor operations such as dumping memory. There are a number of 6800 monitors around the net which might do, and it has several other uses for maintenance. The downside of this is that you really want another interface such as serial on which to dump the data.

There was some discussion in the past about a built-in extension rom in the 9815S upgrade. Did anyone ever determine what it was ? It might be the maintenance rom ..