INTEGRATED CIRCUIT DEVICE AND METHOD AND APPARATUS FOR INSPECTING THE SAME

• US 20010010083A1
• Filed: 07/15/1998
• Published: 07/26/2001
• Est. Priority Date: 07/16/1997
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: SATOH, SHUJI
• Granted Patent: US 6,415,393 B2
• Time in Patent Office: Days
• US Class Current: 714/30
• CPC Class Codes: G06F 11/261 by simulating additional hardware, e.g. fault simulation

Abstract

An integrated circuit device can be inspected in various ways while it is being installed on a circuit board. A bus control unit connects an external memory to a central processing unit in a normal mode. In an inspection mode, the bus control unit connects an inspection control circuit, which has a plurality of registers for temporarily storing instruction codes and data to be processed from an external circuit inspection device, to the central processing unit at a suitable time. When the instruction codes and data from the external circuit inspection are stored in the registers of the inspection control circuit, the central processing unit can be inspected while it is effecting a desired data processing operation.

Claims

1. An integrated circuit device comprising:

a central processing unit for reading instruction codes and data to be processed and executing data processing tasks based on the read instruction codes and data to be processed;

an external bus for being connected to an external information storage medium which stores instruction codes and data to be processed;

an inspection information interface for detachable connection to an external circuit inspection device;

an inspection control circuit connected to said inspection information interface and having a plurality of registers for temporarily storing instruction codes and data to be processed which are supplied from said external circuit inspection device; and

a bus control unit for selectively connecting said external bus and said inspection control circuit to said central processing unit;

said bus control unit having an operation mode switchable between a normal mode and an inspection mode, and means for connecting said external bus continuously to said central processing unit in the normal mode and switching a destination to be connected to said central processing unit from said external bus to said inspection control circuit in said inspection mode when the address of an access destination issued by said central processing unit agrees with the predetermined address of one of the registers of said inspection control circuit.

2. An integrated circuit device according to

claim 1

, wherein said registers of the inspection control circuit include:

an instruction code register for temporarily storing an instruction code for instructing said central processing unit to effect a predetermined data processing operation;

a data register for temporarily storing data to be processed by said central processing unit based on said instruction code stored by said instruction code register; and

a return instruction code register for temporarily storing an instruction code to return an access destination for said central processing unit to said instruction code register.

3. An integrated circuit device according to

claim 1

, wherein said registers of the inspection control circuit include:

an instruction code register for temporarily storing an instruction code for instructing said central processing unit to effect a predetermined data processing operation;

a data register for temporarily storing data to be processed by said central processing unit based on said instruction code stored by said instruction code register; and

a return instruction code register permanently storing a predetermined instruction code to return an access destination for said central processing unit to said instruction code register.

4. A method of inspecting an integrated circuit device according to

claim 2

, comprising the steps of:

storing the instruction code for the predetermined data processing operation in said instruction code register;

storing the data to be processed by said central processing unit in said data register;

storing the instruction code to return the access destination in said return instruction code register;

updating the instruction code stored in said instruction code register and the data stored in said data register when said central processing unit effects the predetermined data processing operation based on said instruction code stored in said instruction code register and said data stored in said data register; and

returning the access destination of said central processing unit to said instruction code register based on said instruction code stored in said return instruction code register.

5. A method of inspecting an integrated circuit device according to

claim 3

, comprising the steps of:

storing the instruction code for the predetermined data processing operation in said instruction code register;

storing the data to be processed by said central processing unit in said data register;

updating the instruction code stored in said instruction code register and the data stored in said data register when said central processing unit effects the predetermined data processing operation based on said instruction code stored in said instruction code register and said data stored in said data register; and

returning the access destination of said central processing unit to said instruction code register based on said instruction code stored in said return instruction code register.

6. An apparatus for an inspecting an integrated circuit device according to

claim 2

, comprising:

a connector detachably connected to said inspection information interface;

instruction code storing means for storing said instruction code for instructing said central processing unit to effect the predetermined data processing operation from said connector through said inspection information interface into said instruction code register;

data storing means for storing the data to be processed from said connector through said inspection information interface into said data register; and

return instruction code storing means for storing said instruction code to return the access destination from said connector through said inspection information interface into said return instruction code register.

7. An apparatus for an inspecting an integrated circuit device according to

claim 3

, comprising:

a connector detachably connected to said inspection information interface;

instruction code storing means for storing said instruction code for instructing said central processing unit to effect the predetermined data processing operation from said connector through said inspection information interface into said instruction code register; and

data storing means for storing the data to be processed from said connector through said inspection information interface into said data register.