5. Secondary Cache Interface

5.2 Secondary Cache Interface Frequencies

The secondary cache interface operates at the frequency of SCClk, which is derived from PClk. The SCClkDiv mode bits select a PClk to SCClk divisor of 1, 1.5, 2, 2.5, or 3, using the formula described in Chapter 7, the section titled "Secondary Cache Clock."

Synchronization between the PClk and SCClk is performed internally and is invisible to the system. The processor supplies six complementary copies of the secondary cache clock on SCClk(5:0) and SCClk(5:0)*.

The outputs and inputs at this interface are triggered by an internal SCClk. The relationship between the internal SCClk and the external SCClk[5:0]/SCClk[5:0]* can be programmed during boot time by setting the SCClkTap mode bits (see the section titled "Mode Bits" in Chapter 8 for detail on mode bits).

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