UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

ortek_service · 3rd Jun 2021, 8:56 am

If the printer interface is just sending ASCII to it, then conversion to a serial terminal display shouldn't need much - maybe able to do it with just a logic IC or so, without needing any uC / firmware.

Yes, it does seem that you need a different (EP)ROM installed for each Z80, 6502, 6800 or 8085 plug-in 'conversion card' PCB adaptor module, rather than just having one program that detecting what adaptor you had.
I suppose this made it simpler to add extra processors they added in future, as you still might have to update a larger EPROM to latest version
- at least with later Softy S3, you uploaded a 'Help ROM' into battery-backed RAM to ensure that its library of devices was fully up to date, for support of the later devices.

I did also notice they sold a clip-over Probe, in case the CPU was soldered-in. - Presumably you needed a different one for each CPU, and it wasn't universal (although not clear from the advert)

I think an updated more-modern maybe Arduino (Mega?) / RPi based version of the Microdoctor could be very useful to aid fixing vintage computers, but I've not really seen anything quite like this. Many years ago, a friend was working on something similar, using an FPGA etc. for Atari Arcade machines, but I think these already had a diagnostic connector and Atari had originally produced a (similarly to Microdoctor, quite rare) unit that plugged into this (May have been a JAMMER? interface, used on other makes).
But once the hardware / firmware of the Microdoctor gets Rev-Eng'd, then that might be helpful in basing any future design on what it did without having to start from scratch too much.

3rd Jun 2021, 8:56 am	#10
ortek_service Octode Join Date: May 2018 Location: Northampton, Northamptonshire, UK. Posts: 1,444	Re: Dataman Microdoctor If the printer interface is just sending ASCII to it, then conversion to a serial terminal display shouldn't need much - maybe able to do it with just a logic IC or so, without needing any uC / firmware. Yes, it does seem that you need a different (EP)ROM installed for each Z80, 6502, 6800 or 8085 plug-in 'conversion card' PCB adaptor module, rather than just having one program that detecting what adaptor you had. I suppose this made it simpler to add extra processors they added in future, as you still might have to update a larger EPROM to latest version - at least with later Softy S3, you uploaded a 'Help ROM' into battery-backed RAM to ensure that its library of devices was fully up to date, for support of the later devices. I did also notice they sold a clip-over Probe, in case the CPU was soldered-in. - Presumably you needed a different one for each CPU, and it wasn't universal (although not clear from the advert) I think an updated more-modern maybe Arduino (Mega?) / RPi based version of the Microdoctor could be very useful to aid fixing vintage computers, but I've not really seen anything quite like this. Many years ago, a friend was working on something similar, using an FPGA etc. for Atari Arcade machines, but I think these already had a diagnostic connector and Atari had originally produced a (similarly to Microdoctor, quite rare) unit that plugged into this (May have been a JAMMER? interface, used on other makes). But once the hardware / firmware of the Microdoctor gets Rev-Eng'd, then that might be helpful in basing any future design on what it did without having to start from scratch too much.