Power management in a seamlessly integrated microcontroller chip
A system that includes a first die with a central processing unit (CPU) and a second die electrically coupled to the first die by die-to-die interconnects is described. During operation, the first die: provides, to the second die, a set of predefined wake-up events; provides, to the second die, a message that transitions power-management control of the first die to the second die; and transitions the first die from a first operating mode to a second operating mode that has lower power consumption than that of the first operating mode. Then, the second die: determines an occurrence of a predefined wake-up event based at least in part on the set of predefined wake-up events; and provides, to the first die, information that initiates a transition of the first die from the second operating mode to the first operating mode.
1. A system, comprising:
a first die with a central processing unit (CPU); and
a second die electrically coupled to the first die by die-to-die interconnects, wherein the first die is configured to:
provide, to the second die, a set of predefined wake-up events;
provide, to the second die, a message that transitions power-management control of the first die to the second die; and
transition the first die from a first operating mode to a second operating mode that has lower power consumption than that of the first operating mode; and
wherein the second die is configured to:
determine an occurrence of a predefined wake-up event based at least in part on the set of predefined wake-up events; and
provide, to the first die, information that initiates a transition of the first die from the second operating mode to the first operating mode.
2. The system of claim 1 , wherein the second die comprises an ASIC die.
3. The system of claim 1 , wherein, in the second operating mode, control logic and memory in the first die are powered off.
4. The system of claim 3 , wherein the control logic comprises a direct memory access (DMA) controller.
5. The system of claim 1 , wherein the information transitions power-management control of the first die back to the first die.
6. The system of claim 1 , wherein the information is provided to a core of the CPU.
7. The system of claim 1 , wherein, in the first operating mode, the first die and the second die are configured to operate power-management units, and operation of the power-management units is coordinated asynchronously between the first die and the second die.
8. The system of claim 7 , wherein the coordination comprises synchronization of state machines associated with the power-management units in the first die and the second die.
9. The system of claim 1 , wherein the set of predefined wake-up events is programmable.
10. The system of claim 1 , wherein the determining comprises translating an interrupt to the predefined wake-up event and the information specifies the predefined wake-up event; and
wherein, after the first die receives the information, the first die is configured to translate the information to the interrupt.
11. The system of claim 10 , wherein the communication via the die-to-die interconnects and the translation of the information to the interrupt enable the CPU to operate as if the interrupt occurred in a single-die system.
12. The system of claim 1 , wherein the predefined wake-up event comprises an interrupt; and
wherein the second die is configured to:
hold the interrupt until the first die transitions to the first operating mode; and
provide, to the first die, the interrupt.
13. The system of claim 12 , wherein the second die is configured to hold the interrupt until the first die transitions to the first operating mode when a debug port on the second die is active.
14. The system of claim 1 , wherein transitioning to the first operating mode comprises powering on and booting the CPU.
15. The system of claim 1 , wherein the information specifies the determined predefined wake-up event.
16. The system of claim 1 , wherein the second die comprises a debug port that is configured to facilitate debugging of the CPU from the second die.
17. A method of performing power management, comprising:
providing, from a first die with a central processing unit (CPU) to a second die that is electrically coupled to the first die by die-to-die interconnects, a set of predefined wake-up events;
providing, from the first die to the second die, a message that transitions power-management control of the first die to the second die;
transitioning the first die from a first operating mode to a second operating mode that has lower power consumption than that of the first operating mode;
determining, by the second die, an occurrence of a predefined wake-up event based at least in part on the set of predefined wake-up events; and
providing, from the second die to the first die, information that initiates a transition of the first die from the second operating mode to the first operating mode.
18. The method of claim 17 , wherein the determining comprises translating an interrupt to the predefined wake-up event and the information specifies the predefined wake-up event; and
wherein, after the first die receives the information, translating, by the first die, the information to the interrupt.
19. The method of claim 17 , wherein the predefined wake-up event comprises an interrupt; and
wherein the method comprises:
holding, at the second die, the interrupt until the first die transitions to the first operating mode; and
provide, from the second die to the first die, the interrupt.
20. An electronic device, comprising:
a first die with a central processing unit (CPU); and
a second die electrically coupled to the first die by die-to-die interconnects, wherein the first die is configured to:
provide, to the second die, a set of predefined wake-up events;
provide, to the second die, a message that transitions power-management control of the first die to the second die; and
transition the first die from a first operating mode to a second operating mode that has lower power consumption than that of the first operating mode; and
wherein the second die is configured to:
determine an occurrence of a predefined wake-up event based at least in part on the set of predefined wake-up events; and
provide, to the first die, information that initiates a transition of the first die from the second operating mode to the first operating mode.