Viewing Issue Advanced Details
|ID||Category [?]||Severity [?]||Reproducibility||Date Submitted||Last Update|
|00040||Misc.||Minor||Have not tried||Jan 16, 2008, 09:09||Jan 18, 2008, 07:06|
|Version||0.122u2||Fixed in Version||0.122u5||Build|
|Fixed in Git Commit||Github Pull Request #|
|Summary||00040: 720: About hacky sound CPU speed.|
I've noticed the z80 (sound cpu)'s speed is elevated for the 720 sets (720, 720g, 720gr1, 720r1, 720r2, 720r3) compared to others in the driver. The driver has a note mentioning: "artificially high to prevent deadlock at startup" and putting this at 2.2mhz instead of the driver base of 1.789772mhz.
I was curious to see if the problem still existed (also, it seemed kind of hacky to raise the CPU above normal to make something work) so I rebuilt a MAME with the CPU speed for 720 back at the driver standard 1.789772mhz. I fired up 720 and noticed a black screen, consistent to the "deadlock" mentioned. So, I went to the Dip menu and activated Service Mode. You know what? It came up! I cycled the Service Mode and all items seemed to work fine. I turned the Service DIP back off - and the game booted and seem to play as intended. Subsequent starting of 720 seems to work fine @ default atarisy2 clock speeds provided there was an NVRAM present.
Not sure if this game actually requires it's NVRAM full before booting, but it seems that way.
|Steps To Reproduce|
|Affected Sets / Systems||720|
|There are no relationship linked to this issue.|
|There are no notes attached to this issue.|