HP 71B Ports

[Christoph Giesselink]

Interesting discussion. I never thought about that I implemented all virtual modules inside Emu71/Win with DAISYIN and DAISYOUT line so that you could put them together in one single "Port".

Interesting also that Emu71/Dos supports the ports 6 and 7 which are accessed by the OS. So a quick look, if Emu71/Win could also simulate the ports 6 and 7. Main question is, could the Emu71/Win document format can handle more than 6 external ports?

Yes, it's possible, but no need.

Emu71/Win until v0.09 was only able to handle 8 logic modules (one HPIL consists of 2 modules in this count) per port. This limitation has gone with v0.10 (first published version was v1.00). So the number of external modules is only limited by the address space of the Saturn CPU.

Minor detail, looking inside the Emu71/Win v1.08beta6 source code I found a bug in the UNCNFG opcode implementation. Modules in Port 1-5 cannot be unconfigured because the un-configuration routine check if the DAISYIN line is high; this is rubbish. But also never seen, that this bug occured, because I never seen that a single module in a port was unconfigured by the UNCNFG opcode.

Any example?