It is currently Fri Nov 17, 2017 9:53 pm

All times are UTC - 7 hours





Post new topic Reply to topic  [ 4 posts ] 
Author Message
 Post subject: M2 and MMC3
PostPosted: Tue Aug 08, 2017 8:45 pm 
Offline
User avatar

Joined: Tue Dec 21, 2004 8:35 pm
Posts: 600
Location: Argentina
The Wiki says:

Quote:
The MMC3 scanline counter is based entirely on PPU A12, triggered on rising edges (after the line remains low for two rising edges of M2).


Can somebody explain me what is "M2"?
Thxs

_________________
ANes


Top
 Profile  
 
 Post subject: Re: M2 and MMC3
PostPosted: Tue Aug 08, 2017 8:55 pm 
Offline
Formerly Fx3
User avatar

Joined: Fri Nov 12, 2004 4:59 pm
Posts: 3075
Location: Brazil
viewtopic.php?f=9&t=10984


Top
 Profile  
 
 Post subject: Re: M2 and MMC3
PostPosted: Tue Aug 08, 2017 9:32 pm 
Offline

Joined: Sun Apr 13, 2008 11:12 am
Posts: 6437
Location: UK (temporarily)
M2 is specifically the external CPU cycle signal.

It is not the master clock.
It is not the APU or DMA clocks.
It is not the PPU pixel or colorburst clock.

In the 2A03, it is high for 5/8 of the time and low for 3/8. The exact phase of it relative to the PPU is random, so the exact rise/fall time of M2 matters relative to PPU events.


Top
 Profile  
 
 Post subject: Re: M2 and MMC3
PostPosted: Tue Aug 08, 2017 10:10 pm 
Offline
User avatar

Joined: Tue Dec 21, 2004 8:35 pm
Posts: 600
Location: Argentina
Thxs a lot to both!!

_________________
ANes


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 4 posts ] 

All times are UTC - 7 hours


Who is online

Users browsing this forum: No registered users and 11 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group