Viewing Issue Advanced Details
|ID||Category [?]||Severity [?]||Reproducibility||Date Submitted||Last Update|
|05387||Timing||Minor||Always||Dec 2, 2013, 00:52||Nov 26, 2019, 16:17|
|Tester||Zaphod||View Status||Public||Platform||MAME (Official Binary)|
|Assigned To||AJR||Resolution||Fixed||OS||Windows Vista/7/8 (64-bit)|
|Version||0.151||Fixed in Version||0.217||Build||64-bit|
|Summary||05387: nibbler: Some animations run too fast.|
The snake warping in animation runs too fast, causing it to finish before the triple sweep does. On real hardware, it syncs precisely with the sound effect.
This is confirmed on video from real boards on youtube.
this has been present for a LONG time.
|Steps To Reproduce||Just start a game. Happens every single time.|
Incidentally, some real boards suffer from this same timing error.
The speed of actual gameplay is probably correct.
I believe similar issues exist with fantasy, because the timing of the ending seems off to me, but i cannot confirm this. but i'm pretty sure it's a general fault in the driver.
|Flags||Verified with Original|
|Affected Sets / Systems||nibbler|
|There are no relationship linked to this issue.|
Dec 2, 2013, 14:46
|I have a fix for this in 0.152 (r26289) by changing the clock rate down to adjust for the issue - but I'm told my divisor is wrong. So, it's not fixed but feels closer. It will need to be reexamined.|
Dec 13, 2018, 23:10
This was fixed in mame 0.152:
-snk6502.c: Adjusted Nibbler board clock rate to use actual known
master clock and a logical divisor. [Tafoid]
Dec 18, 2018, 06:10
|Tafoid stated the divisor is not confirmed, so until we know what it is for certain, this remains open.|
Nov 26, 2019, 16:17
|I've confirmed the actual CPU clock divider from schematics. It's 11.289 MHz divided by 8, but the wait states imposed on most ROM reads effectively cut that frequency in half most of the time. This applies to all games in snk6502.cpp but the earliest ones, which run with a CPU clock divider of 16 and no wait states.|