Clock

From NeoGeo Development Wiki
Revision as of 13:05, 28 February 2016 by Furrtek (talk | contribs)
Jump to navigation Jump to search
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.

LSPC2-A2 divides 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 ?