Abstract: Executing a simulation of a computer platform, the simulation including simulation models. A dynamic quantum is accessed whose current value specifies a maximum number of units of execution a simulation model is allowed to perform without synchronizing with another simulation model. The dynamic quantum may be received from a user. Respective simulation models are invoked for execution with the current value of the dynamic quantum provided to each of the simulation models. The method also comprises modifying the value of the dynamic quantum based on a simulation event.

Abstract: Machine-readable media, methods, and apparatus are described to issue message signaled interrupts. In some disclosed embodiments, a device generates message signaled interrupts in a manner that enables a device driver written with level-sensitive semantics to properly service the device despite the edge-triggered characteristics message signaled interrupts.

Abstract: System and methods for preventing an operating-system scheduler in a computer system from crashing as a result of an uncleared periodic interrupt are disclosed. A periodic interrupt is generated using a real-time clock (RTC) residing on a chipset. A flag indicating a periodic interrupt is entered into a status register associated with the RTC in firmware residing on the CMOS chip, if the status register indicates no periodic interrupt has been pending. An interrupt handler associated with the RTC attempts to handle the periodic interrupt, if pending. If the periodic interrupt is pending after a preset interval of time elapses, a basic-input-output system (BIOS) residing on a memory unit coupled to the chipset generates a system-management interrupt (SMI). If the periodic interrupt is pending after the preset interval of time elapses, a firmware SMI handler residing on the memory unit clears the pending periodic interrupts from the status register.

Abstract: An electronic configuration circuit includes a processing circuit (2610) operable for executing instructions and responsive to interrupt requests and operable in a plurality of execution environments (EE) selectively wherein a said execution environment (EE) is activated or suspended, a first configuration register (SCR) coupled to the processing circuit (2610) for identifying the interrupt request as an ordinary interrupt request IRQ when the execution environment (EE) is activated (EE_Active); and a second configuration register (SSM_FIQ_EE_y) for associating an identification of that execution environment (EE) with the same interrupt request, the processing circuit (2610) coupled (5910) to the second configuration register (SSM_FIQ_EE_y) to respond to the same interrupt request as a more urgent type of interrupt request when that execution environment (EE) is suspended (5920).

Abstract: A scheduler schedules a plurality of periodic events. Each periodic event has an associated periodic interval of time and an associated set of services. The scheduler determines when one of the plurality of periodic events occurs and distributes the execution of the services associated with that periodic event during a next periodic interval of time associated with that periodic event following the occurrence of that periodic event. The services can be enabled and disabled. This allows the services to be executed, for example, in one-shot, burst, and continuous modes.

Abstract: Data is communicated through two separate circuits or circuit groups, each having clock and mode inputs, by sequentially reversing the role of the clock and mode inputs. The data communication circuits have data inputs, data outputs, a clock input for timing or synchronizing the data input and/or output communication, and a mode input for controlling the data input and/or output communication. A clock/mode signal connects to the clock input of one circuit and to the mode input of the other circuit. A mode/clock signal connects to the mode input of the one circuit and to the clock input of the other circuit. The role of the mode and clock signals on the mode/clock and clock/mode signals, or their reversal, selects one or the other of the data communication circuits.

Abstract: A multiprocessor system includes a plurality of processor units each transmitting an interrupt request signal indicating an interrupt request for which an interrupt-request destination processor unit is specified and receiving an interrupt signal and an interrupt control circuit receiving the interrupt request signal from each of the plurality of processor units and transmitting the interrupt signal to each of the plurality of processor units, wherein, the interrupt control circuit transmits the interrupt signal to the interrupt-request destination processor unit specified by the interrupt request signal if the specified interrupt-request destination processor unit is not in a low power consumption state and transmits the interrupt signal to another processor unit different from the processor unit specified by the interrupt request signal if the specified interrupt-request destination processor unit is in the low power consumption state.

Abstract: Disclosed herein is a system and method of operating a processor before and after a reset has been asserted. Prior to a reset being asserted the processor operates in one of a plurality of states wherein primary code may be executed by the processor depending on said state. Upon a reset being asserted the processor begins executing code for a reset routine. The processor also executes a process such that the processor operates in the same state it was in prior to the reset upon the reset no longer being asserted.

Abstract: Interrupts are directed to currently idle processors. Which of a number of processors of a computing system that are currently idle is determined. An interrupt is received and directed to one of the currently idle processors for processing. Determining which processors are currently idle can be accomplished by monitoring each processor to determine whether it has entered an idle state. When a processor has entered an idle state, it is thus determined that the processor is currently idle. Where just one processor is currently idle, an interrupt is directed to this processor. Where more than one processor is currently idle, one of these processors is selected to which to deliver an interrupt, such as in a round-robin manner. Where no processor is currently idle, then one of the processors is selected to which to deliver an interrupt.

Abstract: A first exemplary aspect of an embodiment of the present invention is a multi-thread processor including a plurality of hardware threads each of which generates an independent instruction flow, and an interrupt controller that determines whether or not an input interrupt request signal is associated with one or more than one of the plurality of hardware threads, and when the input interrupt request signal is associated, assigns the interrupt request to an associated hardware thread.

Abstract: Various embodiments of the present invention are directed to augmented interrupt controllers (AICs) and to synthetic interrupt sources (SISs) providing richer interrupt information (or “synthetic interrupts” or “SIs”). The AIC and SIS provide efficient means for sending and receiving interrupts, and particularly interrupts sent to and received by virtual machines. Several of these embodiments are specifically directed to an interrupt controller that is extended to accept and deliver additional information associated with an incoming interrupt. For certain such embodiments, a memory-mapped extension to the interrupt controller includes a data structure that is populated with the additional information as part of the interrupt delivery. Although several of the embodiments described herein are disclosed in the context of a virtual machine system, the inventions disclosed herein can also be applied to traditional computer systems (without a virtualization layer) as well.

Abstract: Embodiments of a system and method for handling interrupts are described herein. In an embodiment interrupts from various client components in a system (also referred to as clients) are processed by an interrupt handler component uniformly. The various clients signal interrupts in different manners. For example, some clients signal interrupts in a level-based manner, and some clients signal interrupts in a pulse-based manner. In an embodiment, all interrupts received by the interrupt handler are formed into an event message according to a uniform format regardless of the manner in which the interrupt is signaled. The event message includes all information necessary for a host processor interrupt service routine (ISR) to service the interrupts without reading hardware registers. Event messages are stored in an event buffer for access and handling by the host. The event buffer is managed by the interrupt handler.

Abstract: An interrupt controller (1) is adapted to control the execution of interrupt requests (11, 12) of differing criticality by a processor (7) which is required to execute tasks (3, 17) of differing criticality under the control of a computer operating system (5); the interrupt controller being adapted to recognize critical (11) and non-critical (12) interrupt requests originating from different interrupt sources, and to recognize when the processor (7) is required to execute each of critical (3) and non-critical tasks (17); the interrupt controller being further adapted to pass critical interrupt requests (11) to the processor (7) for execution in preference to non-critical interrupt requests (12), to block non-critical interrupt requests (12) to the processor when they coexist with critical interrupt requests (11) or the processor (7) is required to execute critical tasks (3), and to pass non-critical interrupt requests (12) to the processor (7) when they do not coexist with any critical interrupt requests (11)

Abstract: An interrupt control unit provides controls on an interrupt from an accelerator to a CPU based on a packet transmitted to or received from a controlled object. The interrupt control unit includes: a storage part for storing therein an interrupt control timing table in which a condition of switching a mode of the interrupt control is described; and an interrupt control mode switching part for switching the mode of the interrupt control to the CPU between a permission mode and a mask mode, based on the interrupt control timing table in the storage part.

Abstract: An apparatus for processing data includes a processor operable in a plurality modes including at least one secure mode being a mode in a secure domain and at least one non-secure mode being a mode in a non-secure domain. When the processor is executing a program in a secure mode the program has access to secure data which is not accessible when the processor is operating in a non-secure mode. The processor is responsive to one or more exception conditions for triggering exception processing using an exception handler. The processor is operable to select the exception handler from among a plurality of possible exception handlers in dependence upon whether the processor is operating in the secure domain or the non-secure domain.

Abstract: An even-driven interrupt processing is efficiently carried out in a multiprocessor system. A main control unit 112 executes a main process as a processing for controlling an apparatus in a unified manner. A sub-control unit 116 executes a task assigned by the main control unit 112 during the execution of the main process, as a sub-process. An event detector 162 detects an event occurrence upon which an interrupt task is to be preferentially executed during the execution of the main process. An interrupt notification unit 164 notifies the sub-control unit 116 of interrupt information indicative of an interrupt task in response to the detected event. The sub-control unit 116 notified of the interrupt information executes the interrupt task specified by the interrupt information, as a sub-process.

Abstract: A receiving apparatus does not frequently activate a host processor in a sleep mode, so that it is possible to reduce a time overhead when the host processor transitions from a sleep mode to a running mode, also suppress power consumed in the overhead time and improve communication performance. With this apparatus, a communication interface circuit (101) extracts packet data from a signal received from a network. A communication interface control circuit (102) decides whether or not packet data is packet data that must be received, and, when the packet data is packet data that must be received, issues an interrupt signal. A power supply circuit (106) supplies power. When receiving the interrupt signal, the host processor (107) executes a program including reception processing.

Abstract: A power control unit (PCU) may reduce the core wake-up latency in a computer system by concurrently waking-up the remaining cores after the first core is woken-up. The power control unit may detect arrival of a first, second, and a third interrupt directed at a first, second, and a third core. The power control unit may check whether the second interrupt occurs within a first period, wherein the first period is counted after waking-up of the first core is complete. The power control unit may then wake-up the second and the third core concurrently if the second interrupt occurs within the first period after the wake-up activity of the first core is complete. The first period may at least equal twice the time required for a first credit to be returned and next credit to be accepted.

Abstract: The serial communication device capable of reducing the load on the CPU is provided for a system using the serial communications such as the car navigation system. The attention is focused on the control method of the serial communication, in which a DMA controller is used for the data reception in the serial communication, and a number larger than the number of data received at a time is set in advance as the number of transfers of the receive DMA controller, and further, the function to generate the timeout interrupt when data is not received for a certain period is added to the serial interface, so that the serial communication can be controlled and performed without applying the load on the CPU.

Abstract: An apparatus for executing secure code, having a microprocessor coupled to a secure non-volatile memory via a private bus a system memory via a system bus. The microprocessor executes non-secure application programs and a secure application program. The microprocessor accomplishes private bus transactions over the private bus to access the secure application program within the secure non-volatile memory. The private bus transactions are hidden from system bus resources and devices coupled to the system bus. The microprocessor includes normal interrupt logic and secure execution mode interrupt logic. The normal interrupt logic provides non-secure interrupts for interrupting the non-secure application programs when the microprocessor is operating in a non-secure mode.

Abstract: An apparatus providing for a secure execution environment. The apparatus includes a microprocessor and an external crystal. The microprocessor is configured to execute non-secure application programs and a secure application program, where the non-secure application programs are accessed from a system memory via a system bus and the secure application program is accessed from a secure non-volatile memory via a private bus coupled to the microprocessor. The microprocessor has a secure real time clock that is configured to provide a persistent time, where the secure real time clock is only visible and accessible by the secure application program when the microprocessor is executing in a secure mode. The external crystal is coupled to the secure real time clock within the microprocessor and is configured to cause an oscillator within the secure real time clock to generate an oscillating output voltage that is proportional to the frequency of the external crystal.

Abstract: An interrupt controller for managing interrupt requests comprises interrupt control circuitry in a first domain, the first domain being switchable to a low-power mode, and interrupt request monitoring circuitry in a second domain. The interrupt control circuitry is responsive to a low power request signal received by the interrupt controller to communicate interrupt select information to the interrupt request monitoring circuitry prior to the first domain being switched to a low power mode, the interrupt select information identifying interrupt requests which indicate exit from the low power mode. The interrupt request monitoring circuitry comprises a select information store configured to store the select information communicated to the interrupt request monitoring circuitry by the interrupt control circuitry.

Abstract: A power control unit (PCU) may reduce the core wake-up latency in a computer system by concurrently waking-up the remaining cores after the first core is woken-up. The power control unit may detect arrival of a first, second, and a third interrupt directed at a first, second, and a third core. The power control unit may check whether the second interrupt occurs within a first period, wherein the first period is counted after waking-up of the first core is complete. The power control unit may then wake-up the second and the third core concurrently if the second interrupt occurs within the first period after the wake-up activity of the first core is complete. The first period may at least equal twice the time required for a first credit to be returned and next credit to be accepted.

Abstract: Disclosed is an interrupt dispatching system and method in a multi-core processor environment. The processor includes an interrupt dispatcher and N cores capable of interrupt handling which are divided into a plurality of groups of cores, where N is a positive integer greater than one. The method generates a token in response to an arriving interrupt; determines a group of cores to be preferentially used to handle the interrupt as a hot group in accordance with the interrupt; and sends the token to the hot group, determines sequentially from the first core in the hot group whether an interrupt dispatch termination condition is satisfied, and determines the current core as a response core to be used to handle the interrupt upon determining satisfaction of the interrupt dispatch termination condition. With the invention, delay in responding to an interrupt by the processor is reduced providing optimized performance of the processor.

Abstract: Embodiments of a computer system and methods for changing operating systems (OSs) can perform a task switching into a different OS without checking a system reset or power off of the system. A method for changing the OS in a multi-OS system can include initializing, at the BIOS, a hardware and dividing an area on the main memory for a booting initiated by an instant-on key/signal; turning over a system control to the embedded OS after loading an embedded OS on a specific area of the divided main memory and booting the same, and operating an instant-on player (IOP). When the IOP is terminated by a user, forcibly loading the normal OS on the main memory. The normal OS can be loaded in a hidden state before termination of the IOP. Thus, a time to reach normal computer system operations from an instant-on-function can be reduced.

Abstract: A system (150) and method provide for the transfer of at least one packet (194) comprising data between a user space (152) and a kernel space (154) associated with a server (156) that is positioned in a distributed network arrangement (192) with a plurality of clients (158, 160, 162, 164). A distribution program (168) associated with the user space (152) is operable to accumulate the at least one packet (194). An application program interface (174) associated with the user space (152) transfers the at least one packet (194) to the kernel space (154) with a number of software interrupts (204). A driver (176) associated with the kernel space (154) is operable to distribute the at least one packet (194) to a subset of the plurality of clients (158, 160, 162, 164) in response to receiving the number of software interrupts (204). The number of software interrupts (204) is less than one software interrupt per packet per client.

Abstract: A computing system having expansion modules. One of the expansion modules is identified as a master module. The other modules act as slaves to the master module. The central processing unit routes a task to either the master module for portioning out or to all of the expansion modules. The master module then receives completion signals from all of the active slave modules and then provides only one interrupt to the central processing unit for that task.

Abstract: A custom interrupt service routine may be developed to handle interrupt requests that would not be appropriately handled by either of two operating system guests in a virtualization technology (VT) environment. In some embodiments, the custom interrupt service routine does not in any way interfere with the operation of the interrupt handling in a non-VT environment.

Abstract: A method for adopting an orphaned I/O port of a storage controller is disclosed. The storage controller has first and second redundant field-replaceable units (FRU) for processing I/O requests and a third FRU having at least one I/O port for receiving the I/O requests from host computers coupled to it. Initially the first FRU processes the I/O requests received by the I/O port and the third FRU routes to the first FRU interrupt requests generated by the I/O port in response to receiving the I/O requests. Subsequently, the second FRU determines that the first FRU has failed and is no longer processing I/O requests received by the I/O port, and configures the third FRU to route the interrupt requests from the I/O port to the second FRU rather than the first FRU, in response to the determining that the first FRU has failed.

Abstract: Data is communicated through two separate circuits or circuit groups, each having clock and mode inputs, by sequentially reversing the role of the clock and mode inputs. The data communication circuits have data inputs, data outputs, a clock input for timing or synchronizing the data input and/or output communication, and a mode input for controlling the data input and/or output communication. A clock/mode signal connects to the clock input of one circuit and to the mode input of the other circuit. A mode/clock signal connects to the mode input of the one circuit and to the clock input of the other circuit. The role of the mode and clock signals on the mode/clock and clock/mode signals, or their reversal, selects one or the other of the data communication circuits.

Abstract: A method and a system for automatically diagnosing disability of computer peripheral devices are provided. In the method, a set of interrupt configuration data relevant to a disabled PCI peripheral device, including relevant setting values of a hardware IRQ routing, is input and compared with a PCI IRQ routing table pre-stored in a boot control unit. Then, whether errors exist in the current setting values of the relevant control parameters and flags of all the relevant control units are automatically checked. If an incorrect setting value is found, a corresponding diagnosis result message is displayed for informing the user to make a modification. Therefore, users can know the reasons that cause the computer peripheral device to operate abnormally and make the modification quickly and effectively.

Abstract: In response to entering a secure mode a processor disables access to first predetermined processor information through a sideband interface, while maintaining access to second predetermined processor information through the sideband interface. In the processor, a first interface portion of the sideband interface may provide access to the first predetermined processor information and a second interface portion of the sideband interface may provide access to the second predetermined processor information. The first interface portion is enabled in response to a power-on sequence and is selectably enabled under software control after being disabled on entering the secure mode. The second and additional interface portions may provides access to information related to processor temperature, power management, or machine checks.

Abstract: Input/output interruptions are managed in computing environments that do not use dedicated per-guest interruption hardware to present interruptions. Dispatchable guest programs in the environment receive I/O interruptions directly without hypervisor intervention. This is facilitated by using one or more interruption controls stored in memory and associated with each guest program. For those guest programs that are not currently dispatchable, interruptions can be posted for the guests and notifications to the hypervisor can be aggregated. The hypervisor can then process a plurality of notifications for the plurality of guests in a single invocation.

Abstract: According to one embodiment, a method is disclosed. The method includes selecting a first of a plurality of programmable interrupt enable registers, a controller determining for the first register whether there interrupts at a queue manager to be processed by a processor, the processor reading an interrupt status register within the queue manager, the processor processing packets corresponding to addresses stored in each of a plurality of queues within the queue manager, selecting a second of a plurality of programmable interrupt enable registers and the controller determining for the second register whether there interrupts at the queue manager to be processed by the processor.

Abstract: A memory access device includes logic to switch data from a processor memory bus to a memory bus in a first operational mode, and to switch data from a test bus to the memory bus in a second operational mode, and logic to switch address signals from the processor memory bus to the memory bus in the first operational mode. In the second operational mode the device accepts from the test bus a starting memory address for memory reads and writes, and automatically and independently of the test bus adjusts a memory address for reads and writes during burst memory operations.

Abstract: An interrupt controller 2 is provided with priority registers 6 storing priority values P0-P9 used to determine prioritisation between received interrupt signals I0-I9. A priority value accessing circuit 10 provides multiple mappings to the priority values stored in dependence upon the priority value manager 16, 18, seeking to make an access. In this way, a first priority value manager 18, such as a secure operating system, can be given exclusive access to the highest priority values whilst a second priority value manager 16, such as a non-secure operating system, can be given access to a range of priority values as stored which are of a lower priority and yet as written or read by the non-secure operating system appear to the non-secure operating system to have a different, such as higher, priority level.

Abstract: In an on-vehicle terminal system operating a plurality of operating systems, control of peripheral devices connected to the on-vehicle terminal system can be continued even if one of the operating systems is stopped. A second operating system monitors an operating status of a first operating system using an OS status monitoring function. When the first operating system stops, a list recording allocation of the peripheral devices is updated to switch the allocation to the second operating system. By doing so, an interrupt signal from a peripheral device is allocated to the second operating system, and accordingly the second operating system can control the peripheral device.

Abstract: The present disclosure describes using the JTAG Tap's TMS and/or TCK terminals as general purpose serial Input/Output (I/O) Manchester coded communication terminals. The Tap's TMS and/or TCK terminal can be used as a serial I/O communication channel between; (1) an IC and an external controller, (2) between a first and second IC, or (3) between a first and second core circuit within an IC. The use of the TMS and/or TCK terminal as serial I/O channels, as described, does not effect the standardized operation of the JTAG Tap, since the TMS and/or TCK I/O operations occur while the Tap is placed in a non-active steady state.

Abstract: Input/output interruptions are managed in computing environments that do not use dedicated per-guest interruption hardware to present interruptions. Dispatchable guest programs in the environment receive I/O interruptions directly without hypervisor intervention. This is facilitated by using one or more interruption controls stored in memory and associated with each guest program. For those guest programs that are not currently dispatchable, interruptions can be posted for the guests and notifications to the hypervisor can be aggregated. The hypervisor can then process a plurality of notifications for the plurality of guests in a single invocation.

Abstract: Data is communicated through two separate circuits or circuit groups, each having clock and mode inputs, by sequentially reversing the role of the clock and mode inputs. The data communication circuits have data inputs, data outputs, a clock input for timing or synchronizing the data input and/or output communication, and a mode input for controlling the data input and/or output communication. A clock/mode signal connects to the clock input of one circuit and to the mode input of the other circuit. A mode/clock signal connects to the mode input of the one circuit and to the clock input of the other circuit. The role of the mode and clock signals on the mode/clock and clock/mode signals, or their reversal, selects one or the other of the data communication circuits.

Abstract: A micro-controller includes a USB control unit, an MC unit having an operation mode and a stop mode and an oscillating circuit, which is commonly used by the USB control unit and the MC unit. The USB control unit includes a watching circuit for watching a condition of a first data and a second data, which is complement data of the first data. The operation of the oscillating circuit is controlled in response to an operation control signal, which is generated by a watching result, and an oscillation control signal whose voltage level is changed in response to the mode of the MC unit.

Abstract: A device and method for switching over in a computer system having at least two execution units are provided, in which switchover units are included which are designed in such a way that they switch between at least two operating modes, a first operating mode corresponding to a comparison mode and a second operating mode corresponding to a performance mode. A programmable interrupt controller is assigned to each execution unit, and a storage element is included, in which information is stored that describes at least parts of a configuration of at least one of these interrupt controllers.

Abstract: Machine-readable media, methods, and apparatus are described to issue message signaled interrupts. In some disclosed embodiments, a device generates message signaled interrupts in a manner that enables a device driver written with level-sensitive semantics to properly service the device despite the edge-triggered characteristics message signaled interrupts.

Abstract: The capability to handle the 100 ?s RPR interrupt and similar interrupts is provided by servicing selected interrupts outside of the operating system. This drastically reduces the latency and overhead associated with servicing the interrupt. A method of handling an interrupt in a computer system comprises receiving the interrupt at the computer system, determining whether the interrupt is a selected interrupt, and performing interrupt processing not involving an operating system of the computer system, if the interrupt is a selected interrupt.

Abstract: An embodiment of the present invention is a technique to process system management interrupt. A system management interrupt (SMI) is received. The SMI is associated with a system management mode (SMM). A conditional SMI inter-processor interrupt (IPI) message is broadcast to at least a processor. The SMI is processed without waiting for the at least processor to check into the SMM. A clear pending SMI is broadcast to the processors at end of SMI processing to clear a pending SMI condition.

Abstract: A processor comprises a first mode of operation and a second mode of operation. A state of the processor in the first mode of operation comprises a first plurality of variables. The first plurality of variables comprises a return address. A state of the processor in the second mode of operation comprises a second plurality of variables in addition to the first plurality of variables. The processor is configured to perform, in case of an interrupt or exception occurring during the second mode of operation, the steps of saving the second plurality of variables and the return address to a buffer memory, replacing the return address with an address of a trampoline instruction, and switching into the first mode of operation. These steps are performed independently of an operating system.

Abstract: A processor provides two-level interrupt servicing. In one embodiment, the processor comprises a storage device and an interrupt handler. The storage device is configured to store an interrupt identifier corresponding to an interrupt request. The interrupt handler is configured to recognize the interrupt request, initiate a common interrupt service routine responsive to recognizing the interrupt request and subsequently initiate an interrupt service routine corresponding to the stored interrupt identifier.

Abstract: Described is a method for processing work items in a data processing system. An interrupt is generated in response to receipt of a work item on a queue and the generated interrupt is serviced to schedule a task by placing the task on a task queue for later processing of the queued work item. The interrupt is not enabled at this point and therefore the receipt of further work items will not result in the generation of interrupts. When the scheduled task reaches the head of the queue, the task is executed to process the queued work item (and all other work items that have been added to the queue since the task was scheduled). When all the work items have been processed, a further task is speculatively scheduled for processing of any work items that are subsequently placed on the work item queue.

Abstract: Data is communicated through two separate circuits or circuit groups, each having clock and mode inputs, by sequentially reversing the role of the clock and mode inputs. The data communication circuits have data inputs, data outputs, a clock input for timing or synchronizing the data input and/or output communication, and a mode input for controlling the data input and/or output communication. A clock/mode signal connects to the clock input of one circuit and to the mode input of the other circuit. A mode/clock signal connects to the mode input of the one circuit and to the clock input of the other circuit. The role of the mode and clock signals on the mode/clock and clock/mode signals, or their reversal, selects one or the other of the data communication circuits.

Abstract: A method of operating a micro controller unit including maintaining a stop mode operation when a battery level detected n response to a first interrupt signal input from an external source is in a predetermined low voltage level range during the stop mode operation, and performing a normal operation corresponding to a second interrupt signal input from the external when a battery voltage level detected in response to the second interrupt signal is higher than the highest voltage level belonging to the predetermined low voltage level range.