SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
The clocks of ISS submodules can be cut individually using the ISS_CLKCTRL register. Software can poll the module status reading the appropriate bit in the ISS_CLKSTAT register.
When software wants to enable a submodule:
Software must enable the modules in the correct order. The hardware imposes no particular constraint. For example, when data must be provided by CAL_B and processed by the ISP, both modules must be enabled and correctly configured before data arrives. For details and the order of configuration, see the programming model of the particular submodule.
When software wants to shut down a submodule:
The ISS does not assert the MWait signal when a shutdown of the module is not requested by software.
Table 9-13 describes the clock gating of the ISS submodule.
ISS Resource | Feature On/Off Control |
---|---|
ISS top-level resources | Not applicable. ISS top-level resources cannot be cut. However, top-level resources support the autogating feature. |
SIMCOP | ISS_CLKCTRL[0] SIMCOP |
ISP | ISS_CLKCTRL[1] ISP |
CAL_B | ISS_CLKCTRL[10] CAL_B |
ISS interconnect | These modules cannot be switched off individually. They are required for any processing performed by SIMCOP because they are on the main data path. However, they support autogating to reduce power consumption when activity is low. |
When the clock of a submodule is cut and an interface bridge request for this module is received from the ISS configuration interconnect, the ISS clock manager temporarily enables the module clock to handle the access properly.
All ISS submodules are off after reset; software must enable them before they can be used.