JP2004021884A - Multitasking processor and mobile communications terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce electric power consumption by improving a system and excluding waste of processing since no task is selected in some selecting means and a sleep state is provided in a base period wherein all effective tasks are in stand-by states between execution intervals and the number of base periods with executed tasks can be reduced. <P>SOLUTION: A control part 6a in a DSP 6 attempts every base timing to select one task with a stand-by time that is set with respect to each task and has already passed from prior execution from entered tasks. If a task is selected, the control part 6a processes the task until the next base timing. If a task can not be selected, the control part 6a provides the sleep state until a new base period. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multitask processor such as a DSP (Digital Signal Processor) for processing a plurality of tasks in a time-division manner, and a mobile communication terminal including the multitask processor.
[0002]
[Prior art]
In a mobile communication terminal, for example, control of some functions such as those related to transmission / reception processing may be performed by firmware processing in a DSP.
[0003]
When a plurality of functions are controlled by a single DSP, the control is performed in a time-sharing manner by a task scheduler. The task scheduler executes a plurality of tasks in a time-division manner by processing one task for each base period divided by a base timing of a 66 μs cycle, for example.
[0004]
Specifically, for example, a task table as shown in FIG. 5 is used. This task table describes all tasks to be executed by the DSP. These tasks have serial numbers. In the task table, the presence or absence of an entry for each task can be set for each task. Then, every time a new base timing arrives, the DSP cyclically searches for a task entered from the task table and executes the hit task.
[0005]
In the example of FIG. 5, there are 26 tasks A to Z, of which 19 entries A to N are entered. In this case, as shown in FIG. 6, first, the task A is hit in the search according to the first base timing, and this task A is executed until the next base timing arrives. Thereafter, each time the base timing is reached, the tasks B to N are sequentially selected and executed. If the task N is executed, the processing is in one order. In FIG. 6, what is indicated as "effective task" is a task executed at each base timing.
[0006]
By the way, the entry of each task is released when the task is completed. In the example of FIG. 6, tasks C, D, L, M, and N have been completed in the first cycle. Therefore, in the second round, tasks A and B and tasks EK are executed at each base timing. In the second round, tasks EK are completed. Therefore, in the third round, tasks A and B are executed at each base timing. In the third round, task A has been completed. Therefore, the only remaining task is task B, and this task B is executed continuously from the fourth round to the n-th round.
[0007]
In this way, the entered tasks are sequentially selected at an equal ratio and are executed in a time-division manner.
[0008]
[Problems to be solved by the invention]
Some tasks require a certain period of time to wait for a response from the control target. For example, in the case of a channel encoder or a channel decoder, it takes a certain time to process data in frame units. That is, it takes a certain time from when the DSP sets the operation of the channel encoder or the channel decoder to when the processing of the channel encoder or the channel decoder is completed. For this reason, if the task for controlling the channel encoder and the channel decoder is executed while the channel encoder and the channel decoder are being processed, the task simply enters a waiting state and no effective processing is performed.
[0009]
In the case of the example in FIG. 6, if the task B is such, and for example, it is in the waiting state from the second round to the (n−1) th round, the DSP performs useless processing at those timings. Power is being wasted. In the case of a mobile communication terminal, such waste of power becomes a serious problem.
[0010]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a multitask processor and a mobile communication terminal capable of reducing power consumption by eliminating waste of processing. It is in.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a standby time set for each of a plurality of valid tasks for a predetermined base period has elapsed since the last execution of the task. The selecting unit attempts to select one task, and if the task can be selected by the selecting unit, the processing control unit assigns the task to the processing unit during the current base period, and causes the processing unit to process the task. However, if the task cannot be selected by the selecting unit, the sleep unit is set to a sleep state in which the processing unit and the selecting unit are not operated until the sleep unit reaches a new base period.
[0012]
By taking such a measure, the execution interval between the same tasks is set to at least the standby time set for the tasks. Then, in the base period in which all the valid tasks are in the standby state during the execution interval, none of the tasks are selected by the selection unit, and the sleep state is set. The number of base periods in which tasks are executed is reduced, and the time for performing processing operations is reduced.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0014]
FIG. 1 is a block diagram of the mobile communication terminal according to the present embodiment.
[0015]
As shown in the figure, the mobile communication terminal according to the present embodiment includes an antenna 1, a duplexer 2, a receiving unit 3, a demodulator 4, a channel decoder 5, a DSP 6, an MPU 7, an MPU interface 8, a channel encoder 9, a modulator 10 , A transmission unit 11 and a wireless environment monitor 12. The receiving section 3 further has a radio section (RF) 3a and an analog front end section (AFE) 3b. The transmission unit 11 further includes an analog front end unit (AFE) 11a and a radio unit (RF) 11b.
[0016]
A downlink radio frequency signal transmitted from a base station (not shown) is received by the antenna 1 and input to the receiving unit 3 via the duplexer 2. In the receiving section 3, the radio frequency signal is separated from other frequency components by the radio section 3a to be a received signal. This received signal is digitally processed by the analog front end unit 3b, and is provided to the demodulator 4. The received signal is demodulated by the demodulator 4 and converted to a baseband. Further, the received signal is subjected to decoding processing for extracting a received signal relating to a desired channel by the channel decoder 5. The received signal extracted by the channel decoder 5 is provided to the DSP 6.
[0017]
The DSP 6 implements functions as the control unit 6a, the decoder 6b, and the encoder 6c by arithmetic processing controlled by firmware processing. The received signal provided from channel decoder 5 to DSP 6 is provided to decoder 6b via control unit 6a. The received signal is subjected to error correction decoding, voice decoding, and the like by the decoder 6b. The decoded received signal is supplied to the MPU 7.
[0018]
The MPU 7 controls the entire mobile communication terminal. The MPU 7 performs, for example, a process for reproducing received voice based on the received signal provided from the decoder 6b. The MPU 7 and the control unit 6a of the DSP 6 mutually exchange information such as various control requests and result responses via the MPU interface 8. The MPU 7 supplies a transmission signal such as a transmission voice signal to the encoder 6c.
[0019]
The transmission signal is subjected to voice coding, error correction coding, and the like by the encoder 6c. Then, the encoded transmission signal is provided to the channel encoder 9 via the control unit 6a. The transmission signal is converted into a frame format in accordance with a wireless protocol by the channel encoder 9. The transmission signal is further provided to a modulator 10, where the signal is modulated to be a signal in a radio frequency band. After that, the transmission signal is converted into an analog signal by the analog front-end unit 11a, and then transmitted by radio to the base station (not shown) via the duplexer 2 and the antenna 1 by the radio unit 11b.
[0020]
The wireless environment monitor 12 monitors the wireless environment for handover control or the like, and provides the monitoring result to the control unit 6a.
[0021]
The control unit 6a, under the control of the MPU 7, controls the receiving unit 3, the demodulator 4, the channel decoder 5, the decoder 6b, the encoder 6c, the channel encoder 9, the modulator 10, the transmitting unit 11, and the radio environment monitoring. To control the vessel 12. To perform this control, the control unit 6a has functions as a task processing unit, a task selection unit, a task processing control unit, and a sleep control unit.
[0022]
Here, the task processing unit performs arithmetic processing and the like in order to actually execute the processing of the task. The task processing unit can arbitrarily change the task to be executed, and the task is assigned by the task processing control unit. The task selection unit selects a task to be assigned to the task processing unit by referring to a task table described later each time the base timing is reached. When a task is selected by the task selecting means, the task processing control unit assigns the task to the task processing means. The sleep control unit sets the DSP 6 to a sleep state until a new base timing arrives when a task is not selected by the task selection unit.
[0023]
FIG. 2A is a diagram illustrating an example of the task table. As shown in FIG. 2, all tasks to be executed by the DSP are described in the task table. Here, nine units for individually controlling the receiving unit 3, the demodulator 4, the channel decoder 5, the decoder 6b, the encoder 6c, the channel encoder 9, the modulator 10, the transmitting unit 11, and the radio environment monitor 12 are respectively provided. Tasks are set and these are described. These tasks have serial numbers. In the task table, the presence or absence of an entry for each task can be set for each task. In the task table, a predetermined waiting time is described for each task. Furthermore, the task table can be set with a base timing value indicating the timing at which each task should be executed next. The standby time is set in consideration of the time required for the control target in each task to perform a predetermined process, and is represented by the number of base timings.
[0024]
Next, the operation of the mobile communication terminal configured as described above will be described.
[0025]
When the control start is requested from the MPU 7, the control unit 6a starts the task scheduler process shown in FIG.
[0026]
First, in step ST1, the control unit 6a performs an initialization process. In this initialization process, the control unit 6a initializes the pointer i and the register save / restore area of each task. The control unit 6a stores the execution start address of each task in adr (). Further, the control unit 6a sets the variable A to “0”.
[0027]
Subsequently, in step ST2, the control unit 6a checks whether or not the variable A is “9”. Here, if it is confirmed that the variable A is not “9”, the control unit 6a performs a pointer increment process in step ST3. In the pointer increment process, the control unit 6a normally increases the value of the pointer i by one. However, when the value of the pointer i is the same as the number of tasks described in the task table, the control unit 6a sets the value of the pointer i to “1”. That is, in the case of the present embodiment, if the value of the pointer i is “1” to “8”, the control unit 6a changes it to “2” to “9”. However, if the value of the pointer i is “9”, the control unit 6a changes it to “1” instead of “10”.
[0028]
Next, in step ST4, the control unit 6a checks the entry of the task whose number is i in the task table. Hereinafter, the task whose number is i in the task table is described as a task (i).
[0029]
If it is confirmed that the task (i) has been entered, the control unit 6a determines in step ST5 that the task (i) has the current base at the next execution timing t1 (i) described in the task table. Check whether the timing value has been reached. Note that the base timing value is a count value that is counted up for each base timing.
[0030]
If it is confirmed in step ST4 that the task (i) has not been entered, or if it is confirmed in step ST5 that the current timing has not reached the next execution timing t1 (i), the control unit 6a Increases the value of the variable A by one in step ST6. Then, the control section 6a shifts the processing to step ST2 and executes the subsequent processing in the same manner as described above.
[0031]
By the way, in the task table, the next execution timing is initially cleared as shown in FIG. 2A, and no effective value is set. When the next execution timing is in such a state, the control unit 6a determines that the current timing has reached the next execution timing t1 (i) in step ST5 regardless of the current base timing value. Alternatively, if the actual value is set in the next execution timing t1 (i) by the processing described later, and the current base timing value is equal to or longer than the next execution timing t1 (i), the control unit 6a determines in step ST5 that It is determined that the current timing has reached the execution timing t1 (i). When it is confirmed in step ST5 that the current timing has reached the next execution timing t1 (i), the control unit 6a determines in step ST7 that the saved task (i) register Is returned to the register, and an address adr (i) at which execution is started is set.
[0032]
Subsequently, in step ST8, the control unit 6a substitutes the current base timing value for the variable t0 in order to hold the current base timing value. Then, the control unit 6a starts task processing in step ST9. Here, since the state in which the processing of the task (i) is performed is set in step ST7, the processing of the task (i) is started.
[0033]
In the state where the task processing is being performed, the control unit 6a waits for the completion of the task being executed or the occurrence of an interrupt in step ST10 and step ST11. Then, when it is confirmed in step ST10 that the task being executed has been completed, the control unit 6a performs a task completion process in step ST12. The task completion process is a process of setting the process to be started from the beginning of the task (i) when the process of the task (i) is executed next time. Specifically, in the task completion processing, the control unit 6a releases the entry of the task table (i). The control unit 6a initializes a register save / restore area for the task (i). Further, the control unit 6a sets the execution start address of the task (i) to adr (i). When this task completion processing is completed, the control section 6a subsequently clears the next execution timing t1 (i) in step ST13.
[0034]
By the way, when a new base timing arrives, an interrupt occurs to the DSP 6. When the occurrence of this interrupt is confirmed in step ST11, the control unit 6a performs a task interruption process in step ST14. The task suspension process is a process for stopping the task process being executed and setting to continue the stopped task process when the process of the task (i) is executed next time. Specifically, in the task suspension process, the control unit 6a saves the contents of all registers at the present time in the register save area of the task (i). Further, the control unit 6a sets an execution address next to the execution address when the task processing is stopped to adr (i). When the task suspension processing is completed, the control unit 6a subsequently sets the next execution timing t1 (i) to the value of the variable t0 by adding the waiting time ts (i) for the task (i) in step ST15. Update to For example, if the process of task (1) is performed when the base timing value is “31”, the standby time ts (1) for task (1) is “1” as shown in FIG. The next execution timing t1 (1) is updated to "32" as shown in FIG. Further, for example, if the process of task (3) is performed when the base timing value is “32”, the waiting time ts (3) for task (3) is “20” as shown in FIG. Therefore, the next execution timing t1 (3) is updated to “52” as shown in FIG.
[0035]
When the next execution timing t1 (i) has been updated in step ST13 or step ST15, the control unit 6a subsequently changes the variable A to “0” in step ST16. Then, the control unit 6a shifts the processing to step ST3, and performs the subsequent processing in the same manner as described above.
[0036]
By the way, as described above, the next execution timing is initially all cleared as shown in FIG. Therefore, in the first cycle, all the entered tasks are sequentially executed at each base timing.
[0037]
Specifically, assuming that the entry is in a state as shown in FIG. 2A, in the first round, the numbers are "1", "3", "4", "6", and "6" as shown in FIG. 8 "are sequentially executed. Then, if the base timing value is as shown in FIG. 4, when the first round is completed, the next execution timing t1 (i) for each task is updated as shown in FIG. 2 (b).
[0038]
At the next base timing, the base timing value is “36”, which is equal to or longer than “32” of the next execution timing t1 (1) for the task (1). Therefore, the task (1) is selected at this base timing, and the task (1) is executed in a period until the next base timing. At the next base timing, the base timing value is “37”, which is smaller than any of the next execution timings of the tasks (3), (4), (6), and (8). Therefore, the tasks (3), (4), (6), and (8) are not selected, and the task (1) whose next execution timing is “37” is continuously selected. Thus, only the task (1) is executed in the second and third rounds.
[0039]
Now, assume that task (1) is completed in the third round. Then, the entry of the task (1) is released, and the remaining entries become the tasks (3), (4), (6), and (8). The next execution timing for these tasks is the smallest, which is “52” of task (3). Therefore, until the base timing having the base timing value of “52” arrives, the control unit 6a determines in step ST5. There is no determination of “YES”. As a result, the control unit 6a repeatedly performs the process of step ST6, and when the check on all nine tasks is completed, the variable A becomes “9”.
[0040]
When it is confirmed in step ST2 that the variable A has become "9", the control unit 6a clears the variable A to "0" in step ST17. Then, in step ST18, the control unit 6a waits for an interrupt to occur. Therefore, no processing is performed in the DSP 6 until the next base timing arrives, and the DSP 6 enters a sleep state. Then, when it is confirmed in step ST18 that the next base timing has arrived and an interrupt has occurred, the control unit 6a shifts the processing to step ST3, and performs the subsequent processing in the same manner as described above. In FIG. 4, the period indicated by “S” as the effective task indicates the period in which the task is in the sleep state.
[0041]
As a result, in each period until the base timing value becomes “52”, the DSP 6 repeatedly enters the sleep state.
[0042]
At the base timing at which the base timing value is “52”, when the pointer i is “3”, the control unit 6a determines “Yes” in step ST4 and determines “YES” in step ST5. . As a result, the task (3) is executed at the base timing. This is the fourth round.
[0043]
Thereafter, the next execution timing for the entered task is the smallest, which is “58” of task (4). Therefore, in the same manner as described above, each period until the base timing value becomes “58”. In, the DSP 6 repeatedly enters the sleep state.
[0044]
Then, the tasks (4), (6), and (8) are executed in each of the periods in which the base timing values are “58”, “59”, and “60”. These are the fifth rounds.
[0045]
As described above, according to the present embodiment, the execution interval between the same tasks is set to at least the standby time set for the tasks. Then, at the base timing when all the tasks entered are in the standby state during this execution interval, no task is selected, and the DSP 6 is put into the sleep state. Therefore, the execution of the task is not wasted, and the power consumption is reduced.
[0046]
Further, according to the present embodiment, a task for which the standby time is set shorter is executed more frequently than a task for which the standby time is set longer. Therefore, tasks that can be executed in a short period can be efficiently processed.
[0047]
Note that the present invention is not limited to the above embodiment. For example, the multitask processor of the present invention can also be realized by using a CPU as a main body and causing the CPU to perform the same processing as the control unit 6a in the above embodiment.
[0048]
The device to which the multitask processor of the present invention is applied is not limited to a mobile communication terminal.
[0049]
The content and number of tasks to be processed may be arbitrary.
[0050]
In addition, various modifications can be made without departing from the spirit of the present invention.
[0051]
【The invention's effect】
According to the present invention, the execution interval between the same tasks is at least equal to or longer than the standby time set for the task, and in the base period in which all valid tasks are in the standby state during this execution interval, the sleep state is set. Therefore, the number of base periods in which the task is executed is reduced, and the time for performing the processing operation is shortened. As a result, it is possible to reduce power consumption without wasting processing.
[Brief description of the drawings]
FIG. 1 is a block diagram of a mobile communication terminal according to an embodiment of the present invention.
FIG. 2 is a diagram showing an example of a task table.
FIG. 3 is a flowchart of a task scheduler process.
FIG. 4 is a diagram showing a specific example of how a task is executed.
FIG. 5 is a diagram showing an example of a conventional task table.
FIG. 6 is a diagram showing a specific example of how a task is executed by a conventional DSP.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Antenna 2 ... Duplexer 3 ... Receiving part 4 ... Demodulator 5 ... Channel decoder 6 ... DSP
6a ... Control unit 6b ... Decoder 6c ... Encoder 7 ... MPU
8 MPU interface 9 Channel encoder 10 Modulator 11 Transmitter 12 Wireless environment monitor

Claims (2)

Processing means for processing the assigned task;
Selecting means for selecting, from a plurality of valid tasks for each predetermined base period, one task for which a standby time set for each of these tasks has already elapsed since the previous execution;
Processing control means for assigning the task to the processing means during the current base period if the task can be selected by the selection means;
A multi-task processor comprising: a sleep unit that causes the processing unit and the selection unit to be in a sleep state until a new base period is reached if a task cannot be selected by the selection unit. Processing means for processing the assigned task;
For each predetermined base period, processing for mobile communication is performed from among valid tasks among a plurality of tasks. Tasks for which a standby time set for each of these tasks has already elapsed since the previous execution. A selection means for selecting one,
Processing control means for assigning the task to the processing means during the current base period if the task can be selected by the selection means;
A mobile communication terminal comprising a multi-task processor comprising: a sleep unit that does not operate the processing unit and the selection unit until a new base period is reached if a task cannot be selected by the selection unit.

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