JPH04284544A - Micro-controller - Google Patents

Abstract

PURPOSE:To provide a micro-controller capable of executing easily the analysis of a fault or the debugging of a system in respect of the micro-controller which incorporates a CPU and a peripheral circuit and is used for a specified purpose. CONSTITUTION:The micro-controller is the micro-controller which incorporates the CPU and the peripheral circuit, and is used for the specified purpose, and it is constituted so as to be provided with a start address setting means 1 to set a log start address, an address discriminating means 2 to discriminate whether the value of a program counter coincides with the set log start address or not, and an address.data storage means 3 to store data on an internal bus corresponding to the address after log start address and the address when the value of the program counter coincides with the set log start address.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microcontroller, and more particularly to a microcontroller that has a built-in CPU and peripheral circuits and is used for a specific purpose. recent years,
Microcontrollers, which have a built-in CPU and peripheral circuits and are used for specific purposes, have increased circuit scale and
As control becomes more complex, debugging and failure analysis are becoming more difficult. Therefore, there is a need for a simple program tracing method.

0002

[Background Art] In recent years, microcontrollers that have a built-in CPU and peripheral circuits and are used for specific purposes have increased in circuit scale and become more complex to control, making on-board real-time debugging difficult. It becomes. Therefore, in conventional microcontrollers, it is difficult to reproduce malfunction phenomena due to the complexity of the circuit, and the current situation is that real-time debugging and failure analysis often rely on logic analyzers and personal experience. As described above, relying on logic analyzers and personal experience for real-time debugging and failure analysis requires an enormous amount of man-hours, which becomes a bottleneck in development.

In particular, in the case of microcontrollers,
Because they have built-in program memory, program addresses, opcodes, operands, etc. cannot be observed from the outside, making failure analysis difficult. Furthermore, it is difficult to trace sudden phenomena such as malfunctions caused by noise or the like.

0004

SUMMARY OF THE INVENTION As described above, conventional microcontrollers require an enormous amount of man-hours for failure analysis. Furthermore, since debugging and failure analysis are performed by relying on a logic analyzer and personal experience, there is also a problem in terms of accuracy. SUMMARY OF THE INVENTION In view of the problems of the conventional microcontrollers described above, an object of the present invention is to provide a microcontroller that can easily perform failure analysis and system debugging. Furthermore, the present invention also aims to capture phenomena such as runaway due to noise, etc., which have been difficult to capture in the past.

[0005]

FIG. 1 is a block diagram showing the principle of a microcontroller according to the present invention. According to the present invention, there is provided a start address setting means 1 for setting a log start address, which is a microcontroller having a built-in CPU and peripheral circuits and used for a specific purpose.
and address determining means 2 for determining whether the value of the program counter matches the set log start address; A microcontroller is provided which is characterized by comprising address/data storage means 3 for storing subsequent addresses and data on an internal bus corresponding to the addresses.

[0006]

According to the microcontroller of the present invention, the log start address is set by the start address setting means 1. Further, the address determining means 2 determines whether the value of the program counter matches the log start address set in the start address setting means 1. Then, when the value of the program counter matches the set log start address, the address/data storage means 3 stores the address after the log start address and the actual data on the internal bus corresponding to the address.

According to the microcontroller of the present invention, the addresses and data stored in the address/data storage means 3 are read out and program tracing is executed. Therefore, according to the microcontroller of the present invention, it is possible to easily perform failure analysis and system debugging, and it is also possible to detect phenomena such as runaway due to noise, etc., which were difficult to detect in the past.

[0008]

Embodiments Hereinafter, embodiments of a microcontroller according to the present invention will be described with reference to the drawings. FIG. 2 is a block diagram showing an embodiment of the microcontroller of the present invention. As shown in the figure, the microcontroller of this embodiment has a ROM (Read Only Memory) 2
1. RAM (Random Access Memo)
ry) 22, program counter 23, IPLA(
Instruction Programmable
Logic Array) 24, register file/
ALU (Arithmetic and Logic)
Unit) 25, internal bus interface 26,
It includes an internal bus 27, a peripheral circuit 28, and a log control section 4.

A program memory is stored in the ROM 21, and the operation code from the ROM 21 is supplied to the IPLA 24 (on the CPU side) via a decoder 24a, and the decoded operands are supplied to the internal bus interface 26. . From IPLA 24 to program counter 23 and register file A
A control signal is supplied to each LU 25, and a control signal is also supplied to the internal bus interface 26. Program counter 23
Address data is supplied from the program counter 23 to the ROM 21, and an address signal is also supplied from the program counter 23 to the internal bus interface 26. An internal bus 27 having an address bus and a data bus allows signals and data to be exchanged between the internal bus interface 26, RAM 22, peripheral circuit 23, and log control unit 4. Here, an address decoder 28a is provided between the internal bus interface 26 and the peripheral circuit 28.

In the above, ROM 21 to peripheral circuit 2
The configuration of No. 8 is the same as the conventional one, and detailed explanation will be omitted. The feature of this embodiment is that a log control section 4 is further incorporated in the conventional microcontroller. That is, the log control unit 4 includes an address decoder 41, a log mode register (start address register) 42, a counter 43, and a log register 44.

The log mode register 42 is a register for setting a start address register for tracing a program. In other words, it is a register for storing the start address of the program part of interest. When the value of the program counter 23 supplied via the internal bus 27 matches the start address register set in the log mode register 42, the counter 43 counts and stores the subsequent addresses, and Data corresponding to the address is stored in the log register 44.

Table 1 below shows the addresses (count values; program counter values) stored in the counter 43 and log register 44 and the actual data on the internal bus 27.

[0013]

[Table 1]

[0014] In the above, the counter 43 is incremented every machine cycle of the CPU, and the actual data output on the internal bus (data bus) 27 at that time is stored in the log register 44. . Furthermore, the addresses after the start address stored in the log control unit 4 and the actual data on the internal bus corresponding to the addresses are continuously stored until the counter 43 (log register 44) overflows. . Further, an address decoder 41 is provided between the log mode register 42 and the internal bus 27, and address data is exchanged via the address decoder 41. Furthermore, the log control unit 4 is configured to issue an interrupt to the program counter 23. Note that the addresses stored in the log control unit 4 in this way and the actual data corresponding to the addresses are read out, program traced, and compared with the data expected during normal operation corresponding to the addresses. This allows failure analysis and system debugging to be performed. Furthermore, according to this embodiment, it is also possible to capture phenomena such as runaway due to noise, etc., which was difficult to capture in the past.

FIG. 3 is a flowchart showing an example of processing in the microcontroller of the present invention. As shown in the figure, in the log control process, first, in step 51, a predetermined address of the program of interest is set in the log mode register 42 as a log start address. Next, if log mode is enabled in step 52, the process proceeds to step 53, where the value of the program counter (
P. C. ) matches the log start address set above.

If it is determined in step 53 that the value of the program counter matches the set log start address, the process proceeds to step 54, where the log counter 4 is
3 is reset and the process proceeds to step 55. If it is determined in step 53 that the program counter value does not match the set log start address, the comparison and determination between the program counter value and the set log start address is repeated until they match.

Next, in step 55, it is determined whether the log counter 43 has overflowed, and if it is determined that the log counter 43 has not overflowed,
That is, if it is determined that the capacity of the log register 44 is not completely filled, the address and the data on the internal bus 27 corresponding to the address are stored in the log register 44 in step 56 . Further, in step 57, the value of the address counter is incremented and the process returns to step 55, whereby the addresses after the log start address and the data on the internal bus 27 corresponding to the addresses are stored.

Then, in step 55, the log counter 43
It is determined whether or not there is an overflow, and the log counter 4
3 has overflowed, that is, when it is determined that the capacity of the log register 44 is completely filled,
Proceeding to step 58, an interrupt to the CPU occurs. Furthermore, the process proceeds to step 59, where the CPU reads out the contents of the log register 44 (log control unit 4) and outputs it to the external port. In this way, the addresses after the log start address and the actual data corresponding to the addresses stored in the log control unit 4 and read out are as follows:
As mentioned above, failure analysis and the like are performed by comparing the data with data expected during normal operation.

[0019]

[Effects of the Invention] As described in detail above, according to the microcontroller of the present invention, failure analysis and system debugging can be easily performed, and furthermore, phenomena such as runaway due to noise etc. that are difficult to detect in the past can occur. can also be captured.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the principle of a microcontroller according to the present invention.

FIG. 2 is a block diagram showing one embodiment of the microcontroller of the present invention.

FIG. 3 is a flowchart showing an example of processing in the microcontroller of the present invention.

[Explanation of symbols]

1...Start address setting means 2...Address determination means 3...Address/data storage means 4...Log control unit 21...ROM (program memory) 22...RAM (data memory) 23...Program counter 24...IPLA 25...Register file/ALU 26...Internal bus interface 27...Internal bus 28...Peripheral circuit 41...Address decoder 42...Log mode register (start address register) 43...Counter (log counter) 44...Log register

Claims (5)

[Claims] 1. A microcontroller having a built-in CPU and peripheral circuits and used for a specific purpose, comprising a start address setting means (1) for setting a log start address, and a program counter value set as described above. address determining means (2) for determining whether the address matches the log start address; and when the value of the program counter matches the set log start address;
A microcontroller comprising address/data storage means (3) for storing an address after the log start address and data on an internal bus corresponding to the address. 2. The microcontroller further comprises program trace execution means for reading addresses and data stored in the address/data storage means (3) and executing program trace. microcontroller. 3. The microcontroller according to claim 1, wherein said address determining means (2) is configured to be executed only when log mode is permitted. 4. A microcontroller having a ROM storing a program, an address generation circuit, an address bus, and a data bus, the log storing addresses after a preset log start address and data corresponding to the addresses. 1. A microcontroller comprising a register, and configured to perform program tracing by reading the contents of the log register. 5. The log register includes an address area that is output to the address bus from the preset log start address until the storage capacity of the log register overflows, and a data bus that corresponds to the address area. 5. The microcontroller according to claim 4, wherein the microcontroller is configured to store data output to the microcontroller.