Power control circuitry for controlling power domains

Power control circuitry for controlling power domains

A data processing apparatus 2 includes a plurality of power domains controlled by respective power control signals PCS. Power control circuitry 22 includes mapping circuitry which maps a plurality of power status signals PSS indicative of the power status of respective power domains, and received from those power domains, to form the power control signals which are then supplied power domains. The mapping circuitry may be controlled by mapping parameters stored within a memory mapped array. The mapping parameters may specify that a given power control signal is either sensitive or insensitive to the power status of a particular other power domain within the data processing apparatus 2. The mapping parameters may be fixed or software programmable. The mapping parameters may be accessible as memory mapped values within a memory address space of a data processing apparatus.

Reset isolation bridge

Reset isolation bridge

Disclosed is an integrated circuit 2 with two domains 4, the first domain has a power controller 22 to control the power state of a device 20 in the second domain based on power management signals exchanged on a power management channel 24 between the domains. The circuit has a reset isolation bridge 40 on the power management channel between the domains. The bridge has first and second interfaces (42, 44 fig 11) to exchange the power management signals with the first and second domains respectively. Isolating circuitry is provided in the bridge to respond to a reset indication 8 indicating reset of one of the domains, to isolate state transitions of the power management signals at the first and second interfaces from each other. The domains may have independent reset trees. In response to a reset indication the isolating circuitry may trigger a state transition of the power management signals at one of the interfaces during a reset period, until the power management signals at the interfaces ...