Clock: Difference between revisions

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[[File:Clkdistribution.png|frame]]
[[File:Clkdistribution.png|frame]]


== In cartridge systems ==
==In cartridge systems==


The main system clock is 24MHz. It is generated and divided by 2, 4 and 24 by [[NEO-D0]] to form the 12MHz clock for [[NEO-ZMC2]], the inverted 6MHz one for the [[video DAC]] and also the 1MHz one for [[NEO-B1]] (?).
The main system clock (sometimes called '''mclk''') is 24MHz. It is generated and divided by 2, 4 and 24 by {{Chipname|NEO-D0}} to provide the 12MHz clock for {{Chipname|NEO-ZMC2}}, the inverted 6MHz one for [[video DAC|video output]] and also the 1MHz one for {{Chipname|NEO-B1}}.


[[LSPC2-A2]] divides the 24MHz clock to 8MHz for the [[YM2610]] and 4MHz for the [[Z80]].
As {{Chipname|LSPC2-A2}} is clocked on both edges of the 24MHz clock, it is able to divide it by 3 and 6 to provide the 8MHz clock for the {{Chipname|YM2610}} and the 4MHz one for the {{Chipname|Z80}}.


The cartridge connector provides access to the 24, 12, 8MHz and 4MHz inverted clock signals.
The cartridge connector provides the {{Sig|24M|24M}}, 12MHz, 8MHz and 4MHz inverted clock signals.


A second quartz is used on NeoGeo systems for generating the color burst frequency for the [[video encoder]]s.
A second quartz is used for generating the color burst needed by composite video, for the [[video encoder]]s.


[[File:clock.png]]
[[File:clock.png]]

Revision as of 02:22, 16 January 2016

File:Clkdistribution.png

In cartridge systems

The main system clock (sometimes called mclk) is 24MHz. It is generated and divided by 2, 4 and 24 by NEO-D0 to provide the 12MHz clock for NEO-ZMC2, the inverted 6MHz one for video output and also the 1MHz one for NEO-B1.

As LSPC2-A2 is clocked on both edges of the 24MHz clock, it is able to divide it by 3 and 6 to provide the 8MHz clock for the YM2610 and the 4MHz one for the Z80.

The cartridge connector provides the 24M, 12MHz, 8MHz and 4MHz inverted clock signals.

A second quartz is used for generating the color burst needed by composite video, for the video encoders.

"B" signals are phase-inverted.

In CD systems

File:Cd2 quartz.jpg
System clock and color burst generation circuit on a CDM3-2 board.

NEO-GRC ?