JP2001034499A - In-circuit emulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately grasp the difference of consumption currents depending on the combination of instructions and the arrangement of the instructions and to easily specify a program consuming the most current during program execution by providing an integration circuit for the consumption current value of a target microcomputer controlled on the basis of event detection in an event detection circuit. SOLUTION: The power supply current Idd of a target microcomputer 6 that is changed in accordance with program execution is sampled by a current value-digital conversion circuit 2, converted into a digital value and sent to an integration circuit 12. Also, an event detection circuit 11 detects the start address of a program, generates a start event signal, and the circuit 12 starts to cumulate outputs of an A/D conversion circuit 5. Then, the microcomputer 6 cumulates a current value consumed while a program is carried out in such a manner that a user sets the front address and end address of the program whose consumption current is desired to be measured to the circuit 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-circuit emulator capable of easily grasping current consumption in executing an arbitrary program area.

[0002]

2. Description of the Related Art In recent years, with the spread of mobile devices, microcomputers have been required not only to improve processing speed but also to reduce power consumption. By the way, the conventional method of reducing the power consumption of the microcomputer device is generally realized by stopping the execution of the program or stopping the clock to stop the operation of the internal unit. However, this does not directly reduce the power consumption at the time of the program operation, and thus has its own limit.

[0003] Therefore, it is important to reduce power consumption during program execution. It is known that the power consumption during program execution can be reduced not only by the number of accesses outside the microcomputer but also by the number of simultaneously operating units, but the optimum program configuration depends on the types and combinations of instructions. Is not easy to find automatically.

In practice, the program is rearranged and executed,
A technique for finding an optimal combination from the measured power consumption is employed. In this case, generally, an LSI tester is used, or the current consumption is measured using a system evaluation device. In the current measurement on the LSI tester, the test program is executed by the LSI tester, and the current consumption is measured by the ammeter. According to this method, control in clock units can be easily performed, so that current measurement can be performed for each instruction execution unit. However, on the other hand, the load differs from the case where the system is operated by incorporating it into an actual system, and thus the measured value often differs greatly from the case where the system is operated by a user system.

On the other hand, in the current measurement in the system evaluation, L
For an SI tester, a system closer to an actual machine is prepared, and a test program is operated there to measure current. In the current measurement in such a system evaluation, the operation can be performed in an environment very close to the user system, so that the current consumption equivalent to that in the case of being incorporated in an actual system can be measured. However, on the other hand, since control cannot be performed for each clock, in many cases, a program is repeatedly executed in a loop to measure current consumption. As described above, in the current measurement in the system evaluation, the current cannot be measured in instruction execution units as in an LSI tester.

In order to solve the above-mentioned problem in the current measurement, there has been reported an apparatus for measuring a current in a target microcomputer in a state where the current is actually connected to a user system using an in-circuit emulator.

FIG. 7 is a block diagram showing the configuration of such a conventional in-circuit emulator 1. As shown in FIG. The conventional in-circuit emulator 1 comprises an IV conversion circuit 4 connected between a power supply terminal of a target microcomputer 6 and a power supply line 3 for supplying a current to the target microcomputer 6 for converting a current value into an analog voltage signal. An A / D converter 5 for converting an analog voltage signal output from the IV converter 4 into a digital value; a target microcomputer 6 for controlling the user system 8; an ICE control circuit 10; It is configured. The current value consumed by the target microcomputer 6 by the IV conversion circuit 4 and the A / D converter 5 is output as a digital value.
The digital conversion circuit 2 is configured.

Next, the operation will be described. In this in-circuit emulator, the current consumption of the power supply line 3 for supplying a current to the power supply terminal of the target microcomputer 6 is converted into a voltage signal by the IV conversion circuit 4, and the voltage signal is further converted into an A / D converter. After 5, a digital value is written into a part of the trace data every clock or every instruction execution, and the current value consumed for each instruction is observed.

In recent years, microcomputers of the pipeline processing type have appeared in order to speed up the system. In such a microcomputer of the pipeline processing type, not only a plurality of units operate at the same time, but also an operation of an internal unit accompanying execution of an instruction,
They do not always operate in the order in which the instructions are arranged. Therefore, even if the measurement result of the current value is left in units of clocks or instructions as in the in-circuit emulator shown in FIG. 7, it is not always necessary that the value accurately represents the current value during operation by the corresponding instruction. Not necessarily.

FIG. 8 is an explanatory diagram showing how an instruction is executed by such a pipeline operation, and FIG. 9 is an explanatory diagram showing an example of trace data in which a current consumption value is written by a conventional in-circuit emulator. is there. FIG.
In the case where an instruction is executed by a pipeline operation as shown in (1), for example, a store instruction fetched at the seventh clock is executed at the tenth clock, and a write operation to the memory accompanying the instruction is executed at the end of the subroutine. It occurs at the twelfth clock after the eleventh clock at which the instruction is fetched. Only by measuring the current consumption for each clock as described above, it is not possible to accurately know the change in the current consumption depending on the combination of instructions.

[0011]

A conventional method of measuring current consumption when executing an instruction by an in-circuit emulator, that is, leaving a measurement result of a current value in clock units or instruction units, thereby consuming the target microcomputer when executing instructions. The current determination method has a problem that when the target microcomputer performs a pipeline process, it is not possible to accurately know a change in current consumption.

SUMMARY OF THE INVENTION An object of the present invention is to provide an in-circuit emulator capable of accurately grasping a difference in current consumption depending on a combination of instructions and an arrangement of instructions and easily specifying a program consuming the most current at the time of program execution. Is to provide.

[0013]

An in-circuit emulator according to the present invention comprises an event detection circuit for detecting an event, and a circuit for integrating the current consumption value controlled based on the event detection in the event detection circuit. It is characterized by having.

An in-circuit emulator according to the present invention comprises:
The execution period of the program area defined by the set start address and end address is detected as an event, and based on the detection result, the current consumption of the target microcomputer within the execution period of the program area is detected as an integrated value. This makes it possible to accurately grasp the difference in current consumption depending on the combination of instructions and the arrangement of instructions, and to easily identify the program that consumes the most current when executing the program.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. The present invention provides an in-circuit emulator having a storage device that measures a power supply current value of a target microcomputer and accumulates the result together with a program execution history, wherein an integrator circuit for a power supply current value controlled by event detection is provided. Features.

FIG. 1 shows an in-circuit emulator 1a having a microcomputer current consumption measuring function according to the present embodiment.
FIG. 3 is a block diagram showing the configuration of FIG. The function of measuring the current consumption of the target microcomputer 6 in the in-circuit emulator 1 a includes a power supply terminal of the target microcomputer 6, a current value-digital conversion circuit 2 connected between the power supply terminal and the power supply line 3, An integration circuit 12 for calculating an integrated value of the current value converted into a digital value output from the value-digital conversion circuit 2; an event detection circuit 11 for detecting an execution address value of a program executed by the target microcomputer 6; A clear signal 13 for clearing the integrated value of the integrating circuit 12 based on an output from the event detecting circuit 11; a trace circuit 7 for recording an execution address 18 of the program and an output result 16 of the integrating circuit 12;
Consists of The current-to-digital conversion circuit 2 calculates I
It has a -V conversion circuit 4 and an A / D converter 5, and outputs a current value consumed by the target microcomputer 6 as a digital value.

Reference numeral 8 denotes a user system controlled by the target microcomputer 6, reference numeral 9 denotes a clock signal supplied to the in-circuit emulator 1a, and reference numeral 10a denotes an ICE control circuit.

FIG. 2 is a block diagram showing the configuration of the integrating circuit 12. The integrating circuit 12 includes an adding (full adder) circuit 15 and a latch circuit 14. The addition result of the adding circuit 15 is sampled for each clock by a clock signal. Then, the current value (power supply current value) converted into a digital value is added to the integrated value up to immediately before. The current value calculated by the integrating circuit 12 is recorded by the trace circuit 7. The integrated value output from the latch circuit 14 is initialized to “0” by a clear signal output from the event detection circuit 11.

FIG. 3 is a circuit diagram showing the configuration of the event detection circuit 11. The event detection circuit 11 includes address latches 20 and 21, comparators 22 and 23, and an RS flip-flop (integration operation control circuit) 19. The address latch 20 holds an event condition set by the user (here, an integration start address). The address latch 21 holds an event condition set by the user (here, an end address of integration). The comparator 22 outputs a match signal 24 when the program execution address signal matches the start address. The comparator 23 outputs a match signal 25 when the program execution address signal matches the end address.

The RS flip-flop 19 is set when the program execution address reaches the start address specified by the user, and is reset when the program execution address reaches the end address specified by the user. This RS flip-flop 19
Is output to the integrating circuit 12 as a clear signal for clearing the latch circuit 14 shown in FIG. 2 except during the program execution period from the start address to the end address.

The block diagram shown in FIG. 1 includes a reading means for reading data accumulated from the trace circuit 7,
Means for setting the start address and the end address to the event detection circuit 11 are not shown, but are well known to those skilled in the art, and since they are not directly related to the present invention, the detailed configuration is omitted.

Next, the operation of this embodiment will be described. FIG. 4 is a timing chart showing the operation of each unit shown in FIG. As shown in the timing chart of FIG. 4, the power supply current Idd of the target microcomputer 6 that changes with the execution of the program is sampled for each clock by the current-to-digital conversion circuit 2 and is converted to a digital value. Sent. Apart from this, the event detection circuit 11 compares the program execution address signal with a start address (1200H in this case) set in advance by the user. Then, the start address of the program is detected at the fourth clock, and a start event signal is generated.

Since the clear signal of the integrating circuit 12 is released by this start event signal, A / A
Start integrating the output of the D conversion circuit 5 (4 clocks to 14
clock). Further, in the event detection circuit 11, a stop event is generated for the end address (1268H) (14 clocks), and the clear signal becomes active. The output of the integrating circuit 12 so far is recorded in the trace circuit 7 together with a program execution address signal and the like.

As described above, the start address and the end address of the program area where the user wants to measure the current consumption are stored in the address latches 20 and 2 of the event detection circuit 11, respectively.
By setting the value to 1, the current value consumed while the target microcomputer 6 executes the area of the program is integrated by the integration circuit 12.

FIG. 5 shows a display example of trace data recorded in the trace circuit 7 in the present embodiment.
This trace data is the result of measuring the current consumed in the subroutine. In FIG. 5, since the data is processed so that only the data at the end of the subroutine (final value of the integration result) is displayed, the change in the current consumption at each passage of each subroutine becomes clear.

FIG. 6 shows an integrated section of the current consumption set by the start address and the end address when the target microcomputer 6 in the present embodiment is operating in the pipeline processing mode. FIG. 11 is an explanatory diagram showing the current consumption when the operation of the pipeline processing method is performed, which can be accurately grasped as its integrated value.

Therefore, the user can not only obtain the effect of specifying the program that consumes the most current at the time of executing the program, but also depends on the combination of instructions and the arrangement of instructions caused by the operation of the pipeline processing method. The difference in current consumption can be accurately grasped, and the user can efficiently change to a program optimized for low power consumption.

In the above-described embodiment, the current consumption of the target microcomputer 6 is measured as the current flowing from the power supply line 3 to the target microcomputer 6, but the target microcomputer between the target microcomputer 6 and the ground is measured. Alternatively, a configuration may be adopted in which the current value flowing from 6 to the ground or the current value considering both of them is measured. With such a configuration, there is an effect that the current consumption of the target microcomputer 6 can be measured in consideration of the input and output of signals to and from the user system 8.

[0029]

As described above, according to the present invention, not only can the program that consumes the most current during program execution be specified, but also the difference in current consumption when the program in that area is changed is clarified. This makes it easy to efficiently change to a program that consumes the least amount of current. In addition, there is an effect that a difference in current consumption depending on a combination of instructions or an instruction arrangement caused by the operation of the pipeline processing method performed in most recent microcomputers can be accurately grasped.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an in-circuit emulator according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an integrating circuit in the in-circuit emulator according to the embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of an event detection circuit in the in-circuit emulator according to the embodiment of the present invention.

FIG. 4 is a timing chart showing the operation of each unit of the in-circuit emulator according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a display example of trace data recorded in a trace circuit in the in-circuit emulator according to the embodiment of the present invention.

FIG. 6 is an explanatory diagram showing an integrated section of current consumption when the target microcomputer in the in-circuit emulator according to the embodiment of the present invention performs an operation of the pipeline processing method, in comparison with a conventional trace section.

FIG. 7 is a block diagram showing a configuration of a conventional in-circuit emulator.

FIG. 8 is an explanatory diagram showing how an instruction is executed by a pipeline operation.

FIG. 9 is an explanatory diagram showing an example of trace data in which a current consumption value by a conventional in-circuit emulator is written.

[Explanation of symbols]

1a: In-circuit emulator, 11: Event detection circuit, 12: Integration circuit, 14: Latch circuit,
15 ... addition circuit, 19 ... RS flip-flop (integration operation control circuit), 20, 21 ... address latch, 22, 23 ... comparator.

Claims (4)

[Claims] 1. An in-circuit emulator that measures a current consumption value of a target microcomputer and accumulates the measurement result together with a program execution history. An in-circuit emulator for detecting an event, and an event detection circuit for detecting an event. An in-circuit emulator characterized by comprising: a circuit for integrating the current consumption value controlled by: 2. The method according to claim 1, wherein the event detection circuit defines a program area in which the integration circuit integrates a current consumption value based on a program execution address signal and a set start address and end address. The in-circuit emulator according to claim 1, wherein 3. An event detection circuit comprising: an address latch for holding a set start address and an end address; and a comparator for comparing the start address and the end address held in the address latch with a program execution address. And an integration operation control circuit for controlling start and end of the integration operation of the consumed current value by the integration circuit based on the coincidence signal output from the comparator. In-circuit emulator. 4. An accumulator circuit for adding a sampling current consumption value of the target microcomputer to a current consumption integrated value immediately before, for holding and outputting an addition result of the addition circuit, and for holding the held addition result. A latch circuit for providing a result to the addition circuit as a current consumption integrated value up to the immediately preceding time, wherein the integration operation control circuit outputs a reset release signal of the latch circuit based on a coincidence signal output from the comparator. Is generated, and the reset of the latch circuit is released during the execution of the program area defined by the start address and the end address, based on the reset release signal, and the current consumption value of the target microcomputer by the integrating circuit is released. 4. The in-circuit emulator according to claim 3, wherein the integrating operation is controlled.