Microprocessor having a low-power mode and a non-low power mode, data processing system and computer program product
First Claim
1. A microprocessor having a low power mode and a non-low power mode, said microprocessor comprising:
- a processor core for executing instructions provided to said microprocessor;
a clock driver for a clock providing a clock signal which in said non-low power mode has a first frequency and in said low power mode has a second frequency lower than said first frequency;
a hardware timer connected to the clock driver, the hardware timer for scheduling an execution of an event by said microprocessor at a future point in time, and to store a first counter value representing a remaining period of time between a current point in time and the future point in time as a number of clock cycles of said clock signal at the first frequency; and
a timer controller for storing, in response to said microprocessor switching from said non-low power mode to said low power mode after the hardware timer is started, a second counter value that is a second number of clock cycles at the first frequency from a start point to the current point of time, calculating, in response to said microprocessor switching from said non-low power mode to said low power mode after the hardware timer is started, a third counter value based on the first and second counter values, the third counter value is a number of clock cycles of the clock signal at said second frequency that corresponds to the remaining period of time represented by the number of clock cycles of the clock signal at the first frequency, and storing the third counter value to represent the remaining period of time between the current point of time and the future point in time as the number of clock cycles of the clock signal at the second frequency, wherein the hardware timer is set to expire at the future point in time in response to the third counter value of the hardware timer.
25 Assignments
0 Petitions
Accused Products
Abstract
A microprocessor has a low-power mode and a non-low power mode. The microprocessor includes a processor core for executing instructions provided to the microprocessor and a clock providing a clock signal, which in the non-low power mode has a first frequency and in the low power mode has a second frequency lower than the first frequency. A hardware timer is present, for scheduling an execution of an event by the microprocessor at a future point in time. The hardware timer is connected to the clock for determining a period of time between a current point in time and a point in time the event based on a number of clock cycles of the clock signal. A timer controller can determine, when the data processing system switches from the low power mode to the non-low power mode, a number of clock cycles of a clock signal with the first frequency that corresponds to a low-power mode period during which the microprocessor has been in the low power mode and adjusting the hardware timer based on the determined number.
31 Citations
20 Claims
-
1. A microprocessor having a low power mode and a non-low power mode, said microprocessor comprising:
-
a processor core for executing instructions provided to said microprocessor; a clock driver for a clock providing a clock signal which in said non-low power mode has a first frequency and in said low power mode has a second frequency lower than said first frequency; a hardware timer connected to the clock driver, the hardware timer for scheduling an execution of an event by said microprocessor at a future point in time, and to store a first counter value representing a remaining period of time between a current point in time and the future point in time as a number of clock cycles of said clock signal at the first frequency; and a timer controller for storing, in response to said microprocessor switching from said non-low power mode to said low power mode after the hardware timer is started, a second counter value that is a second number of clock cycles at the first frequency from a start point to the current point of time, calculating, in response to said microprocessor switching from said non-low power mode to said low power mode after the hardware timer is started, a third counter value based on the first and second counter values, the third counter value is a number of clock cycles of the clock signal at said second frequency that corresponds to the remaining period of time represented by the number of clock cycles of the clock signal at the first frequency, and storing the third counter value to represent the remaining period of time between the current point of time and the future point in time as the number of clock cycles of the clock signal at the second frequency, wherein the hardware timer is set to expire at the future point in time in response to the third counter value of the hardware timer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A microprocessor having a low power mode and a non-low power mode, said microprocessor comprising:
-
a clock driver for clock to provide a clock signal which has a first frequency when the microprocessor is in the non-low power mode and has a second frequency lower than the first frequency when the microprocessor is in the low power mode; a hardware timer being connected to the clock, the hardware timer for scheduling an execution of an event by said microprocessor at a future point in time, and to store a first counter value representing a remaining period of time between a current point in time and the future point in time as a number of clock cycles of said clock signal at the first frequency; and a timer controller for storing, in response to said microprocessor switching from said non-low power mode to said low power mode after the hardware timer is started, a second counter value that is a second number of clock cycles at the first frequency from a start point to the current point of time, calculating, in response to said microprocessor switching from said non-low power mode to said low power mode after the hardware timer is started, a third counter value based on the first and second counter values, the third counter value is a number of clock cycles of the clock signal at said second frequency that corresponds to the remaining period of time represented by the number of clock cycles of the clock signal at the first frequency, and storing the third counter value to represent the remaining period of time between the current point of time and the future point in time as the number of clock cycles of the clock signal at the second frequency, wherein the hardware timer is set to expire at the future point in time in response to the third counter value of the hardware timer. - View Dependent Claims (13, 14, 15, 16)
-
-
17. A method comprising:
-
producing a clock signal which has a first frequency when a microprocessor is in a non-low power mode, and which has a second frequency lower than the first frequency when the microprocessor is in a low power mode; scheduling, by a hardware timer, an execution of an event by the microprocessor at a future point in time; determining a period of time between a start point in time and the future point in time of the event based on a number of clock cycles of the clock signal at the first frequency; storing the number of clock cycles in the period of time as a first counter value; storing a second counter value in response to the microprocessor being switched from the non-low power mode to the low power mode, wherein the second counter value is a second number of clock cycles at the first frequency from the start point; storing a third counter value in response to the microprocessor being switched from the low power mode to the non-low power mode, wherein the third counter value is a third number of clock cycles at the second frequency while the microprocessor was in the low power mode; calculating a fourth counter value based on the second and third counter values, wherein the fourth counter value is the third number of clock cycles of the clock signal at said second frequency that corresponds to the same number of clock cycles of the clock signal at the first frequency; and calculating an adjusted counter value based on the first, second, third, and fourth counter values, the adjusted counter value to represent the remaining period of time between when the microprocessor switches from the low power mode to the non-low power mode and the future point in time, wherein the hardware timer is set to expire at the future point in time in response to the adjusted value of the hardware timer. - View Dependent Claims (18, 19, 20)
-
Specification