10.1.3. ATB clocking using ATCLKEN

All ATB logic within the processor operates at an integer multiple of ATCLK that is the same frequency as or slower than the ATB clock, ATCLK, using ATCLKEN. Figure 10.5 shows the behavior of ATCLKEN. In this figure, ATCLKEN remains asserted, changing the ATCLK:internal ATCLK frequency ratio from 4:1 to 1:1.

Figure 10.5. Changing the ATCLK-to-internal-ATCLK ratio from 4:1 to 1:1


If ATCLKEN is not used, then it must be tied HIGH. This results in all state in the ATB logic being clocked by ATCLK directly.

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