Clock

Not to be confused with the real time clock (RTC), which is clocked independently.



=In cartridge systems=

The main system clock (often called mclk) is either 24MHz (MVS) or 24.167829MHz (AES). It is generated and divided by 2, 4 and 24 by from a crystal oscillator, to provide the 12MHz clock for, the inverted 6MHz one for video output and also the 1MHz one for.

divides it by 3 and 6 to provide the 8MHz clock for the and the 4MHz one for the.

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

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

A third 32768Hz quartz oscillator is used for the RTC.



"B" signals are phase-inverted.

Signals

 * : 12MHz
 * : 12MHz
 * : Really 3MHz ?
 * : 12MHz
 * : Really 3MHz ?
 * : Really 3MHz ?
 * : Really 3MHz ?
 * : Really 3MHz ?
 * : Really 3MHz ?

=In CD systems=



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