Interested in studying a pre-PC dump?

[RetroAND]

Hello,

I have seen you studied many variants of the code of the IBM PC keyboard, and you did it very nicely.

The case is that I dumped the code in the Datamaster keyboard; for your information The Datamaster is the predecessor of the PC, as such, even the keyboard retains similarities between the one from the System/23 and the PC. If you were interested, I could provide the backup for study purposes.

Sorry for the hassle and thank you in advance!

[tpimh]

How do you dump the ROM of a 8048? Can same technique be applied to dump the ROM of a 6805? The reason I am asking is I want to study the firmware of IBM Model M keyboard, and it seems that nobody ever dumped it.

I think you can just publish your ROM dump, so someone with the required skills and knowledge can analyze it.

[RetroAND]

The 8048 is a product of an era where security wasn't a thing. Therefore they had methods to read the internal ROM at will. But then they found people copying the designs and using the same code and the tech industry decided to restrict the usage of microcontrollers. For this reason more modern microcontrollers cannot be dumped, and verification is usually made inside the device.

The Keyboard ROM is stored at bitsavers and in the Internet Archive, along with the rest of dumped firmware.

[Halicery]

Sorry for the late answer and thank you for your kind offer, @RetroAND! But it's been many years.. and I'm not working on this project anymore. The reason I started was to get answers how to program the PC 8042 properly, how the UPI firmware handles, when both devices are "firing" in the same time. Since the 72X8455 analysis this is considered finished.

The two 8048 dump was done "just for fun". It's easy to be carried away, when you're into something for a while. It's also quite time consuming. Anyway, I assume your dump code would be very similar to those I looked at.

@tpimh, if you manage to dump the Motorola that would be a gem!

[tpimh]

From what I have read, it's possible to dump these chips. I have found multiple references to HD6805_Reader software (unfortunately, all links to it are dead) and MC6805P2_clone.

Model M controller boards use either HD6805V1 or EF6805U3. I don't know how many different firmware versions exist, but I am interested in the one that implements XT/AT automatic protocol switching.