Jurgen Kramer

Verified for both the S1985 and S3527. Indeed all three PPI ports are mirrored: a8h -> ach a9h -> adh aah -> aeh WRT S1985 vs S3527, The S1985 has...

As mentioned this is an -undocumented- feature of both engines. It is not listed in the datasheets. It is not a new discovery I have been using this 'feature' since...

> I assume all 4 PPI ports are mirrored (thus also 0xab -> 0xaf). > Should be easy to implement in openMSX (= adapt the machine description files). > >...

Looking further into this to determine what could be the cause of the port mirroring (at least for the PPI part). It seems they either intentionally did not connect address...

@MBilderbeek I gues you mean 3 devices? (PSG, PPI and VDP). I'll create a simple DOS program to check for those IO port mirroring. I'll put it in my github...

Ok, this is the list: `printer : 90-91h -> 94-95h` `psg : a0-a3h -> a4-a7h` `ppi : a8-abh -> ac-afh` `vdp : 98-9bh -> 9c-9fh`

Forgot the RTC. `printer : 90-91h -> 94-95h` `psg : a0-a3h -> a4-a7h` `ppi : a8-abh -> ac-afh` `vdp : 98-9bh -> 9c-9fh` `rtc : b4-b5h -> b0-b1h` ? The...

@MBilderbeek now you are making this confusing. I initially started this issue about mirrored ports for the PPI. You and others added/talked about more mirrored ports. So I drew up...

@MBilderbeek np. Just a quick first test result while testing on a Wavy23 (S3527): ppi ports: mirrored psg ports: mirrored vdp ports: mirrored print ports: mirrored RTC: not mirrored [S3527...

A first version of my check utility is ready for testing. https://github.com/lintweaker/msxstuff/tree/master/tools Some of the checks are 'simple' these only compare IO port readouts. Behavior of the two engines is...