Single-chip microcomputer with dynamic burn-in test function and dynamic burn-in testing method therefor

A single-chip microcomputer comprising:

• a nonvolatile semiconductor memory device;
• write, read and erase circuits, connected to said nonvolatile semiconductor memory device, for performing a write operation, a read operation and an erase operation upon said nonvolatile semiconductor memory device, respectively;
• an interface;
• a sequencer means for receiving first data via said interface from the exterior to write said first data into said nonvolatile semiconductor memory device, reading said first data from said nonvolatile semiconductor device to compare said first data with second data read via said interface from the exterior thus performing a verification upon said nonvolatile semiconductor memory device, and reading third data from said nonvolatile semiconductor memory device and transmitting said third data via said interface to the exterior.

A dynamic burn-in test method for two single-chip microcomputers each including a nonvolatile semiconductor memory device, comprising the steps of:

• writing a test program into the nonvolatile semiconductor memory devices of said single-chip microcomputers to operate said single-chip microcomputers using said test program;
• performing a flash erase operation upon the nonvolatile semiconductor memory device of one of said single-chip microcomputers, after said single-chip microcomputers are operated;
• moving a first content of the nonvolatile semiconductor memory device of the other of said single-chip microcomputers to the nonvolatile semiconductor memory device of the one of said single-chip microcomputers, after the nonvolatile semiconductor memory device of the one of said single-chip microcomputers is erased;
• and
• comparing the first content of the nonvolatile semiconductor memory device of the one of said single-chip microcomputers with a second content of the nonvolatile semiconductor memory device of the other of said single-chip microcomputers, thus carrying out a verification of the nonvolatile semiconductor memory device of the one of said single-chip microcomputers.

A dynamic burn-in test method for at least first, second and third single-chip microcomputers connected in a ring shape, each including a nonvolatile semiconductor memory device, comprising the steps of:

• writing a test program into the nonvolatile semiconductor memory devices of said first, second and third single-chip microcomputers to operate said first, second and third single-chip microcomputers using said test program;
• performing a flash erase operation upon the nonvolatile semiconductor memory device of said first single-chip microcomputer, after said first, second and third single-chip microcomputers are operated;
• operating said first single-chip microcomputer to receive data from said third single-chip microcomputer, compare the data from said third single-chip microcomputer with data of the nonvolatile semiconductor memory device, and transmit “0” data to said second single-chip microcomputer;
• operating said second single-chip microcomputer to receive the data from said first single-chip microcomputer, perform an OR logic operation upon the data from said first single-chip microcomputer and data of the nonvolatile semiconductor memory device of said second single-chip microcomputer, and transmit result data of said OR logic operation to said third single-chip microcomputer;
• and
• operating said third single-chip microcomputer to receive the data from said second single-chip microcomputer, perform an OR logic operation upon the data from said second single-chip microcomputer and data of the nonvolatile semiconductor memory device of said third single-chip microcomputer, transmit result data of said OR logic operation to said first single-chip microcomputer when the second single-chip microcomputer coincides with the data of the nonvolatile semiconductor memory device of said third single-chip microcomputer, and transmit the data from said second single-chip microcomputer to said first single-chip microcomputer when the data from said second single-chip microcomputer does not coincide with the data of the nonvolatile semiconductor memory device of said third single-chip microcomputer.