80-Bus News

Observations

PROG (Version 0.7) is a reasonable program that provides all that is necessary (and a little more) for easy straight-forward programming of EPROMs. The ability to load and save data to/from various files is a useful feature, as is the limited editing. Those requiring more extensive editing features (such as block moves or block fills) will have to resort to loading the data file under a debugger such as Gemdebug, ZSID, or DDT and using their facilities. The display option is useful as it lets you visually check the buffer contents before programming. (This ensures that you have loaded the correct file and that it does contain what you think it does.)

The only obvious omission is the ability to program a limited range of addresses within the EPROM. At the moment it is a case of ‘all or nothing’. (Mind you the software does not bother to program any byte that is 0FFh, so this can be got around in a roundabout way although the ‘verify’ code may complain rather!)

In general the ESCape key acts as an abort key to return you to the main menu. However this feature does not work during programming, and there is no visual echo of the progress of the programming operation. I assume this is to reduce the display/​polling overhead that would otherwise occur and cause an increase in the overall programming time, but it is a pity that it has been omitted. Perhaps this will be changed in a later release of the software.

General comments

It is nice to see the programmer as a separate unit rather than an 80-BUS card. If anyone has ever used a system where the programmer was on a plug-in card they will know the frustrations of that approach. (You have to work with the lid off the computer and have to juggle the cards around to get the EPROM card into a position where you can actually get EPROMs into and out of the socket – The socket is more often than not vertical, and when you flick the lever to release the EPROM it often falls out into the guts of the computer!)

If you do not have a disk-based system, or want some unusual feature in your control software, the file PROGINIT.MAC contains the low level drivers that form part of PROG. If you are writing software to be ‘PROM’ed then it is likely that you should be able to add your own control routine to Proginit although you will have to do a certain amount of detective work to work out exactly what to do. PROGINIT.MAC – I think it should actually be PROGINIT.C judging by the comments at the start – starts off with a section of comments that tells you what bits where control what. (e.g. Bit X of the control latch selects a Vcc of 5v or 6v, set bit Y for 2lv programming voltage, etc.) What it leaves you to work out for yourself are the bit. combinations required for the various EPROM types.

Conclusions

The Gemini EPROM programmer is fairly obviously targeted on Gemini Galaxy and Quantum users, but any Multiboard/​Gemini/​Nascom owner running CP/M should be able to use the package without any difficulty. (N.B. The screen display of PROG.COM is obviously orientated towards the Gemini IVC/SVC.) Those without disk systems will have to write some of the support software themselves.