2.3.1 Clocking

The Cortex®‑R8 processor includes the CLK, PERIPHCLK, and PERIPHCLKEN clocks. In addition, the DUALPERIPHCLK clock is present if lock-step or split/lock is implemented.

CLK

This is the main clock of the Cortex®‑R8 processor. All the cores in the device and the SCU are clocked with a distributed version of CLK. It is also the main clock for the ETMs and the local CoreSight™ infrastructure.

PERIPHCLK

This signal clocks the interrupt controller, global timer, private timers, and watchdog. PERIPHCLK must be synchronous with CLK, and the PERIPHCLK clock period, N, must be configured as a multiple of the CLK clock period. This multiple N must be equal to, or greater than two.

PERIPHCLKEN

This is the clock enable signal for the interrupt controller and timers. The PERIPHCLKEN signal is generated at CLK clock speed. PERIPHCLKEN HIGH on a CLK rising edge indicates that there is a corresponding PERIPHCLK rising edge.

The following figure shows an example of clocking the peripherals using these enable signals at a 3:1 ratio.

Figure 2-2 Clocking example on MPCore peripherals
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DUALPERIPHCLK and DUALPERIPHCLKEN

This clock and clock enable signal are present if lock-step or split/lock is implemented.

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