KR101356700B1 - Recognize method of interrupt generation - Google Patents

Abstract

A method of recognizing interrupt occurrence is disclosed. According to an embodiment of the present disclosure, a method of recognizing an interrupt occurrence may include detecting a logic level of an external interrupt signal output from an external device, and an initial state and a changed state according to a logic level of an external interrupt signal changed according to an interrupt occurrence. And setting the change state to a trigger level of the interrupt generation, and after the external interrupt signal transitions to the trigger level, resetting the trigger level to the initial state. The initial state is a value of the external interrupt signal before the interrupt is first generated, and the change state is a value of the external interrupt signal when the interrupt occurs. An interrupt generation recognition method according to an embodiment of the present invention may enable an edge triggered interrupt to be generated without adding an additional device by using a level triggered interrupt generator.

Description

Recognize method of interrupt generation

The present invention relates to a method for recognizing an interrupt occurrence, and more particularly, to a method for recognizing an interrupt occurrence that can enable an edge triggered interrupt generation without an additional device by using a level triggered interrupt generation device.

Between two or more devices, provided in a general hardware device, it is essential to synchronize the operation of the two or more devices. That is, when there is a main device and a sub device, the main device recognizes a specific event occurring in the sub device, and accordingly, an operation is required in which the main device solves a specific event occurring in the sub neglect. . For example, if there is a central processing unit as a main device and a keyboard as a secondary device, when an external user presses a specific key of the keyboard, the central processing unit performs an operation that should occur as the specific key is pressed. Here, the sub device is an external device provided outside the main device.

Thus, when a specific event occurs in the secondary device, the primary device accepts the specific event as an interrupt request. Then, in response to the interrupt request of the secondary device, the specific request of the interrupt is identified, and an interrupt service routine (ISR) is performed accordingly.

There are two main ways to recognize and handle interrupts in the main device: level trigger (LT) and edge-trigger (ET). 1A and 1B, an interrupt recognition method according to a level trigger method and an edge trigger method will be described in detail.

1A is a diagram for explaining a method of recognizing interrupt generation in a level trigger method.

The level trigger method recognizes the occurrence of an interrupt by recognizing a specific signal level of a signal (an external signal) for notifying the occurrence of an interrupt.

Here, the external signal is a signal output from a sub device, and is a signal having information on interrupt generation.

Referring to FIG. 1A, when the external signal 101 reaches a logic high level, an interrupt occurrence is notified at regular intervals. When the external signal is at a certain level (logical high level), an interrupt request is generated at a predetermined operating period (T). Since the level trigger method, an interrupt is generated during a time interval when the external signal becomes a logic high level. Accordingly, the main device performs the required operation according to the interrupt request. In this case, performing an operation required according to an interrupt request is called performing an interrupt service routine (ISR).

Referring to FIG. 1A, an interrupt request is generated at each of 103, 105, and 107 time points, and the main device recognizes the interrupt occurrence of the above-described sub device. Accordingly, the main device recognizes the interrupt occurrence occurring at 103 and performs the first ISR 111, and recognizes the interrupt occurrence occurring at 105 and performs the second ISR 113.

Here, in the level trigger method, the ISR performance of the primary device and the external signal level of the secondary device should be synchronized. In other words, after the external signal level is logic high (activation level) and thus the ISR is completed, the external signal level must be logic low (disabled level) again.

If the ISR performance of the primary device and the external signal level of the secondary device are not synchronized, the external signal continues to be active, and the primary device repeatedly performs ISR. Accordingly, a problem arises in that the central processing unit, which is the main unit, cannot perform other operations while performing a specific ISR.

Here, a separate synchronization scheme is required to synchronize the ISR of the primary device and the external signal level of the secondary device. In addition, in order to synchronize, a separate port for transmitting a signal for synchronizing is transmitted from an externally mounted secondary device to a primary device. That is, additional hardware devices and software devices are required. This additional device adds a problem of increasing the manufacturing cost of the interrupt processing device.

In addition, the level trigger method is configured to generate an interrupt when an external signal maintains a certain level (eg, logic high). Therefore, if the section in which the external signal becomes logic high occurs in a short period for the time required for the interrupt generation recognition in the main device, the main device misses the interrupt generation of the secondary device. That is, interruption does not occur when the section in which the external signal becomes a specific level is short.

In addition, the level trigger method recognizes the occurrence of an interrupt and performs interrupt masking (interrupt masking-not detecting an interrupt occurrence) while performing a specific ISR to prevent another interrupt from being generated while performing the specific ISP. Referring to FIG. 1A, while performing ISR 111 in response to an interrupt request 103, it does not respond to another interrupt (not shown) generated during t1 to t2. Therefore, due to interrupt masking, there is a problem that missed generation of interrupts.

FIG. 1B is a diagram for explaining interrupt generation in an edge trigger method. FIG.

Referring to FIG. 1B, the edge trigger method is a method of recognizing occurrence of an interrupt by recognizing a state change of a signal (an external signal) for notifying occurrence of an interrupt. For example, when an external signal transitions from a logic low to a logic high, and when a state changes from a logic high to a logic low, an interrupt may be recognized.

Here, the external signal is a signal output from a sub device mounted outside the main device, and is a signal having information on interrupt generation.

Since the edge trigger method generates an interrupt only when a phase change of an external signal occurs, there is no need for a device necessary for synchronization or an operation and device for interrupt masking as in the level trigger method.

Referring to FIG. 1B, the level trigger method generates an interrupt request 155 at a time t10 at which an external signal phase changes from a logic low to a logic high. Then, the host device recognizes the request 155 and performs an ISR (161).

A part 153 indicates that noise occurs in an external signal. When noise occurs, the phase of the external signal changes instantaneously. However, the edge trigger method recognizes that an interrupt has occurred when only a phase change occurs, and thus the main device recognizes an interrupt occurrence and performs ISR in response to a phase change of an external signal caused by noise. In FIG. 1B, ISR performance according to noise generation 153 is not illustrated.

Accordingly, in the edge trigger method, there is a problem in that an apparatus capable of filtering noise included in an external signal must be additionally provided in order to prevent interruption caused by noise.

In addition, the external is configured to generate an interrupt both when the external signal changes state from logic low to logic high (rising edge) and when the state changes from logic high to logic low (falling edge). In the case of a device, the main device must recognize which edge is the edge of the two cases described above. Therefore, it is necessary to additionally use an apparatus for determining which edge (polling edge or rising edge).

For example, in the use of a hold key of a cellular phone device (a key for a user to lock and unlock a cell phone device), an external signal generates an interrupt at both the rising edge and the falling edge. That is, it is assumed that the external signal is set to the logic high level when the lock is set, and the external signal is set to the logic low level when the lock is released. Then, when an interrupt occurs at the rising edge of the external signal, the main device recognizes the lock setting, and when an interrupt occurs in the polling jay, the main device recognizes the unlock.

However, if an external signal changes state due to a sudden situation, but the main device does not recognize the occurrence of an interrupt, the hold key operates in reverse. To prevent this situation, it is necessary to know the current state of the external signal when interrupts are generated and recognized. However, there is a problem that an additional device (for example, General Port I / O) must be installed to determine the external signal state.

In addition, the edge trigger method does not generate an interrupt for a state change of an external signal generated before the interrupt service routine (ISR) is initialized. An interrupt request from a secondary device that occurred before the primary device initialized the interrupt operation device is unacceptable to the primary device.

For example, a state change of an external signal is used to recognize an MMC card entering a PDA phone. When the MMC card (sub device) is inserted into the PDA phone (main device), it sets the external signal to a logic high level, and when it is ejected, it sets the external signal to a logic low level. However, when the PDA phone is turned off and then on again, the PDA phone does not know whether the MMC card is mounted or released in the PDA phone. This is because the edge trigger method recognizes the 'state change' of the external signal itself, but not the specific level.

Therefore, the edge trigger method has a problem that the initial state of the external signal is not recognized due to the initialization of the external device.

An object of the present invention is to provide a method of recognizing interrupt generation that can enable the generation of interrupts in the edge trigger method without the addition of additional devices by using the level trigger type interrupt generator.

According to an embodiment of the present disclosure, a method of recognizing an interrupt occurrence may include detecting a logic level of an external interrupt signal output from an external device, and an initial state and a changed state according to a logic level of an external interrupt signal changed according to an interrupt occurrence. And setting the change state to a trigger level of the interrupt generation, and after the external interrupt signal transitions to the trigger level, resetting the trigger level to the initial state.

The initial state is a value of the external interrupt signal before the interrupt is first generated, and the change state is a value of the external interrupt signal when the interrupt occurs.

Preferably, the external interrupt signal is a signal having information on whether the interrupt has occurred in the external device, and one signal level and the other signal level of the external interrupt signal are information of the interrupt occurrence and the interrupt ratio generation, respectively. It includes.

Preferably, the interrupt generation method may further include determining that an interrupt has occurred in the external device when the external interrupt signal transitions to the trigger level, and performing a specific operation requested by the interrupt from the external device. have.

Preferably, the interrupt generation method may further include resetting a corresponding interrupt information value stored in an interrupt pending register after performing the specific operation.

Preferably, the interrupt generation method, after the step of resetting the trigger level to the initial state, if the external interrupt signal transitions to the rescheduled trigger level, performing the specific operation requested by the interrupt from the external device; It may be further provided.

Preferably, the interrupt generation method may further include maintaining the change state at the trigger level when the logic level of the external interrupt signal is not the same as the trigger level to prepare for the interrupt occurrence.

Preferably, the interrupt generation method does not perform an interrupt masking operation after the external interrupt signal transitions to the trigger level.

Preferably, the setting of the initial state and the change state may include setting the initial state and the change state to logic low and logic high, respectively, when the external device generates the interrupt in the rising edge state of the external interrupt signal. Can be.

Preferably, the setting of the initial state and the change state may include setting the initial state and the change state to logic high and logic low, respectively, when the external device generates the interrupt at the falling edge state of the external interrupt signal. Can be.

An interrupt generation recognition method according to an embodiment of the present invention sets an initial state and a changed state in an initialization step for interrupt generation, and resets the trigger level to the initial state after an external interrupt signal transitions to the trigger level. By using the level trigger type interrupt generator, it is possible to enable the edge trigger type interrupt generation without adding an additional device.

In addition, an edge trigger type interrupt may be generated even without a noise removing filter. In addition, an interrupt masking operation does not need to be performed while the interrupt is being generated, thereby improving the operation speed performance.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Like reference symbols in the drawings denote like elements.

2 is a diagram for explaining an interrupt generation and processing apparatus used in the present invention.

The interrupt generation recognition method according to the present invention uses an interrupt generation and processing apparatus driven by a level trigger method.

Referring to FIG. 2, an interrupt generating and processing device may be included in the main device 270. The sub device 210 provided outside the main device 270 notifies the main device 270 of the occurrence of an interrupt via an external signal.

The sub-device 210 operates according to the flowchart shown therein. First, the secondary device 210 monitors generation of an interrupt in units of a predetermined operation cycle (step 211). If the interrupt has not occurred, the monitoring operation of step 211 is continued.

If an interrupt has occurred, the logic level of the external interrupt signal is changed (step 213). By the control operation of step 213, the external interrupt signal 221 is changed in logic level and transmitted to the main device 270 through the 220 signal line.

The interrupt generating and processing apparatus 250 provided in the main apparatus 270 operates according to the flowchart shown therein.

First, the external interrupt signal 221 is received and it is determined whether the interrupt (step 251). Operation 251 will be described in detail with reference to operations 305 to 320 (305, 310, 315, and 320) of FIG. 3A.

The interrupt service routine (ISR) is called and the interrupt service routine (ISR) is executed (steps 253 and 255). Steps 253 and 255 are described in detail in steps 325, 330, and 335 of FIG. 2.

The main device 270 may further include an interrupt pending register 260. The interrupt pending register 260 is a device that stores the generation state in a separate register when an interrupt occurs. For example, if an interrupt occurs for the first operation, the 261 register cell value may be set to logic high. In addition, an interrupt-free state can be set to logic low. For example, the first operation may be when the 'A' keyboard is pressed, the second operation may be when the 'B' keyboard is pressed, the third operation may be when the 'C' keyboard is pressed, or the like. have. In response to the interrupt request, the interrupt generation and processing apparatus 250 may execute the interrupt service routine so that the letter 'A' is displayed on the monitor in response to the interrupt request generated by pressing the 'A' keyboard.

3A is a flowchart illustrating a method of recognizing an interrupt occurrence according to an embodiment of the present invention.

Referring to FIG. 3A, a method of recognizing interrupt generation according to an embodiment of the present invention detects a logic level of an external interrupt signal (step 305). As described above, the external interrupt signal may have a logic low or logic high level. The logic level of the external interrupt signal is determined.

The interrupt generation and processing apparatus used herein is a level trigger type interrupt generation and processing apparatus as described above in FIG. Therefore, the logic level at a specific point in time of the external interrupt signal can be grasped without adding a separate device. Accordingly, in the subsequent step, the initial state of the external interrupt signal is identified, and the initial state and the change state of step 310 are set, so that the above-described problems of the prior art (the external signal state recognition problem and the external in the level trigger method) are established. Problem of initial state recognition of a signal).

In step 305, by detecting the initial logic level of the external interrupt signal, it is possible to determine what is the current state of the secondary device (or external device).

For example, if the flash memory externally mounted on the cellular phone device has been mounted on the cellular phone before turning on the cellular phone, the state of the flash memory (secondary device) may be determined through operation 305.

Here, the external interrupt signal is a signal having information on whether an interrupt has occurred in the external device (or the secondary device). Then, one signal level and the other signal level of the external interrupt signal each contain information of the interrupt occurrence and the interrupt ratio occurrence. Here, an interrupt is generated when a specific situation set by the user occurs.

The initial state and the change state are set (step 310). Here, the initial state is a logic level value of the external interrupt signal before the interrupt is first generated. The change state is an external interrupt signal value when an interrupt occurs. For example, if an interrupt occurs only when the external interrupt signal is in a logic high state, the logic high level is changed and the logic low level is initialized.

First, the change state is set to a trigger level of interrupt generation (step 315). Since the change step is set in step 310, the trigger level is set using the change step. The trigger level is a logic level of an external interrupt signal that is recognized as long as an interrupt has occurred. When the external device receives the external interrupt signal, when the external interrupt signal reaches the trigger level, it determines that an interrupt has occurred and executes the corresponding interrupt service routine.

It is determined whether the external interrupt signal is set to the trigger level set in step 315 (step 320). That is, since the change state value is set as the trigger level in step 315, it is determined whether or not the external interrupt signal has reached the change level set in step 310.

After the external interrupt signal transitions to the trigger level in step 420, the trigger level is reset to the initial state set in step 310 (step 330). In other words, once an interrupt occurs (after the external interrupt signal becomes the trigger level), the trigger level is changed. Here, if there is an operation in which the external interrupt signal transitions to the trigger level set in step 315, it may be determined that an interrupt has occurred.

The method for recognizing an interrupt occurrence according to an embodiment of the present invention may further include step 425.

As a result of the determination in step 320, if the external interrupt signal reaches the change level set in step 315, the corresponding interrupt service routine (ISR) requested by the secondary device is performed (step 325). For example, suppose the secondary device is the keyboard and the primary device is the central processing unit. When the "Delete" key on the keyboard is pressed, the external interrupt signal goes to a logic high level. Then, the logic high level is set to the change level, and accordingly the trigger level is set to the change level (ie, the logic high level). Subsequently, as the user presses the keyboard, if the external interrupt signal has reached a logic high level (step 320), the central processing unit (main unit) erases characters displayed on the screen (monitor), etc. (the corresponding ISR). Let this be done.

In addition, the method for recognizing an interrupt occurrence according to an embodiment of the present invention, after performing the corresponding interrupt service routine (ISR) in step 425, resetting the corresponding interrupt information value in the interrupt pending register. C) may be further provided.

In addition, in the method of recognizing an interrupt generation according to an embodiment of the present invention, after the step 430, when the external interrupt signal transitions to the reset trigger level, performing an operation requested by the external device as an interrupt (not shown). It may be further provided.

As a result of the determination in step 320, if the external interrupt signal does not become the trigger level, the trigger level is maintained at the change level set in step 315. Then, the interrupt service routine ISR is prepared or waiting (step 335).

Preferably, the interrupt generation recognition method according to an embodiment of the present invention does not perform an interrupt masking operation after the external interrupt signal transitions to the trigger level.

FIG. 3B is a diagram for describing interrupt generation according to an external interrupt signal state in FIG. 3A.

In FIG. 3B, an example in which an external interrupt signal changes to a logic high level when an interrupt occurs is described.

Referring to FIG. 3B, the logic low level of the external interrupt signal is set to an initial state, and the logic high level is set to a changed state. Then, the change state is set to the trigger level. Since the external interrupt signal has transitioned to the trigger level at time t1, an interrupt request of 371 occurs. In response to the interrupt request, step 325 performs the corresponding interrupt service routine.

Since the interrupt request is generated once, the trigger level is reset to an initial state (logical low level) according to the operation of step 330. Accordingly, a 373 interrupt request is generated at a time t2 when the external interrupt signal changes from logic high to logic low.

As shown in FIG. 3B, another method for recognizing interrupt generation according to an embodiment of the present invention uses an interrupt generation and processing apparatus of a level trigger method, but the edge of an external interrupt signal (such as an edge trigger method) may be changed. Interrupt request).

In addition, although the interrupt request may be generated at each edge of the external interrupt signal, the problem of the edge trigger method (described above, the external signal state recognition problem and the initial state recognition problem of the external signal, and an additional device for solving the problems) Problem) can be solved.

FIG. 4A is a flowchart illustrating a method of recognizing interrupt generation of FIG. 3A applied to an external device generating an interrupt at a falling edge.

Referring to FIG. 4A, since an interrupt should occur at the falling edge, the initial state and the changed state are logic high level and logic low level, respectively. In step 415 of FIG. 4A, the trigger level in step 315 of FIG. 3A becomes a logic low level. In step 430 of FIG. 4A, the trigger level of step 330 of FIG. 3A becomes a logic high level.

All other operations are the same as illustrated and described in FIG. 3A, and thus detailed descriptions thereof will be omitted.

FIG. 4B is a flowchart illustrating a method of recognizing interrupt generation of FIG. 3A applied to an external device generating an interrupt at a rising edge.

Referring to FIG. 4B, since an interrupt must occur at a rising edge, the initial state and the changed state are logic low level and logic high level, respectively. In step 456 of FIG. 4B, the trigger level of step 315 of FIG. 3A becomes a logic low level. In step 480 of FIG. 4B, the trigger level of step 330 of FIG. 3A becomes a logic high level.

All other operations are the same as illustrated and described in FIG. 3A, and thus detailed descriptions thereof will be omitted.

As described above, optimal embodiments have been disclosed in the drawings and the specification. Although specific terms have been used herein, these terms are only used for the purpose of describing the present invention and are not intended to limit the scope of the present invention as defined in the claims or the claims. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

FIG. 1A is a diagram for explaining occurrence of an interrupt in a level trigger method.

FIG. 1B is a diagram for explaining interrupt generation in an edge trigger method. FIG.

2 is a view for explaining an interrupt generating apparatus used in the present invention.

3A is a flowchart illustrating a method of recognizing an interrupt occurrence according to an embodiment of the present invention.

FIG. 3B is a diagram for describing interrupt generation according to an external interrupt signal state in FIG. 3A.

FIG. 4A is a flowchart illustrating a method of recognizing interrupt generation of FIG. 3A applied to an external device generating an interrupt at a falling edge.

FIG. 4B is a flowchart illustrating a method of recognizing interrupt generation of FIG. 3A applied to an external device generating an interrupt at a rising edge.

Claims (9)

Detecting a logic level of an external interrupt signal output from an external device; Setting an initial state and a changed state according to a logic level of an external interrupt signal that changes according to an interrupt occurrence; Setting the change state to a trigger level of the interrupt occurrence; Resetting the trigger level to the initial state after the external interrupt signal transitions to the trigger level, And the initial state is a value of the external interrupt signal before the interrupt is first generated, and the change state is a value of the external interrupt signal when the interrupt is generated. The method of claim 1, wherein the external interrupt signal is A signal having information about whether the interrupt has occurred in the external device, wherein one signal level and the other signal level of the external interrupt signal include information of the interrupt occurrence and the non-interrupt occurrence, respectively; Recognition method of occurrence. The method of claim 2, wherein the recognition method of generating the interrupt And determining that the external device has an interrupt when the external interrupt signal transitions to the trigger level, and performing a specific operation requested by the external device as an interrupt. The method of claim 3, wherein the recognition method of generating the interrupt And after performing the specific operation, resetting the corresponding interrupt information value stored in the interrupt pending register. The method of claim 2, wherein the recognition method of generating the interrupt And after the resetting of the trigger level to the initial state, when the external interrupt signal transitions to the reset trigger level, performing an operation requested by the external device as an interrupt. Recognition method of occurrence. The method of claim 2, wherein the recognition method of generating the interrupt And if the logic level of the external interrupt signal is not the same as the trigger level, maintaining the change state at the trigger level to prepare for the interrupt occurrence. The method of claim 2, wherein the recognition method of generating the interrupt And after the external interrupt signal transitions to the trigger level, an interrupt masking operation is not performed. The method of claim 2, wherein the setting of the initial state and the change state And when the external device generates the interrupt in the rising edge state of the external interrupt signal, sets the initial state and the changed state to logic low and logic high, respectively. The method of claim 2, wherein the setting of the initial state and the change state And when the external device generates the interrupt in the falling edge state of the external interrupt signal, sets the initial state and the changed state to logic high and logic low, respectively.

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