SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
A clock domain is a group of modules fed by clock signals controlled by the same clock manager in the PRCM module (see Figure 3-3). By gating the clocks in a clock domain, the clocks to all the modules belonging to that clock domain can be cut to lower their active power consumption (that is, the device is on and the clocks to the modules are dynamically switched to ACTIVE or INACTIVE [gated] state). Thus, a clock domain allows control of the dynamic power consumption of the device.
The device is partitioned into multiple clock domains and each clock domain is controlled by an associated clock manager within the PRCM module. This allows the PRCM module to activate and gate individually each device clock domain.
Figure 3-3 is an example of two clock managers: CM_a and CM_b. Each clock manager manages a clock domain. The clock domain of CM_b is composed of two clocks, a functional clock (FCLK2) and an interface clock (ICLK1), while that of CM_a consists of a clock (CLK1) that is used by the module as functional and interface clock. The clocks to Module 2 can be gated independently of the clock to Module 1, thus ensuring power savings when Module 2 is not in use.
The PRCM module lets software check the status of the clock domain functional clocks. The CM_<Clock domain>_CLKSTCTRL[x] CLKACTIVITY_FCLK/<Clock name>_FCLK bit in the PRCM module identifies the state of the functional clock(s) within the clock domain. Table 3-10 lists the two possible states of the functional clock.
CLKACTIVITY Bit Value | Status | Description |
---|---|---|
0x0 | Gated | The functional clock of the clock domain is inactive. |
0x1 | Active | The functional clock of the clock domain is running. |
CLKACTIVITY Bit Value | Status | Description |
---|---|---|
0x0 | Gated | The interface clock of the clock domain is inactive. |
0x1 | Active | The interface clock of the clock domain is running. |
All Clock Domains are summarized and described in Section 3.6.4, Clock Domains.