SGCPU - EVPC1 - VDPINT question

[mizapf]

If you made it past the topic title, maybe you can also give me some information.

 

I also contacted Michael Becker, but I don't know whether the address is still valid.

 

Addressing owners of a SNUG SGCPU (aka TI-99/4P): The EVPC (rel. 1) needs a separate cable to deliver the VDP interrupt and GROMCLK into the TI console. In contrast, the SGCPU is located inside the PEB, together with the EVPC and the HSGPL.

 

My question is: How is the VDPINT delivered to the SGCPU? Is it the same cable which now plugs into the SGCPU card somewhere, or do they use some unused line inside the PEB? The hardware manuals are not really clear about that.

 

(Background: I'm doing some small changes in the emulation in MESS, cleaning away some "cheats".)

 

 

[mizapf]

I guess that I found it, and Harald Glaab also agreed: The EVPC sends the VDPINT via the cable and via the LCP* line in the PEB. This line is also described as "Second Generation CPU indicator" (whence the name of the SGCPU). The EVPC2 can be jumpered to route the interrupt via INTA (EXTINT).

[kl99]

nice to hear you move closer towards accurate emulation
BR Klaus