KR20000003933A - Method and device for testing internal memory in memory chip - Google Patents

Abstract

PURPOSE: A method and device for testing an internal memory in memory chip is provided to effectively perform a testing operation of internal memory using a boundary scan. CONSTITUTION: Method and device including an internal memory block, wherein the device for testing the internal memory block in the semiconductor chip of the boundary scan IEEE 1149.1 standard comprises a control register for adding a command for testing the internal memory block, and for restoring the control sign and data for testing the internal memory block in a user test data register.

Description

Method and apparatus for testing internal memory in memory embedded chip

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to functional verification that must be passed in semiconductor chip design, and more particularly, to a method and apparatus for testing an internal memory embedded in a chip.

Most of the recently designed chips include an internal memory, which requires accurate testing of the internal memory. To this end, conventionally, a test pad (PAD) (address, data and control signal) for a test was separately assigned and controlled directly from the outside. However, such a prior art increases the total number of pads by keeping the pads separate, thereby causing problems such as cost increase and packaging.

Another conventional method for testing the internal memory is to test the internal memory through multiplexor logic without using a separate test pad and using common pads in common, which is complicated to control and multiplexer And a decrease in the overall execution speed due to the control logic and an increase in the wiring area in the layout.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a method and an apparatus for testing an internal memory in a memory embedded chip that efficiently performs an internal memory test using a boundary scan. have.

1 is a block diagram illustrating a chip architecture implementing the standard BS1149.1.

2 is an internal block diagram of a standard BS test circuit.

3 conceptually illustrates a control register in accordance with the present invention that defines a user test data register to control an internal memory;

Figure 4a is an internal configuration diagram of the control unit according to the present invention.

4b is an internal configuration diagram of a data unit according to the present invention;

Figure 5a is an internal configuration of the cell constituting the control unit of Figure 4a in accordance with the present invention.

5B is a diagram illustrating an internal configuration of a cell constituting the data unit of FIG. 4B according to the present invention.

6 is a state machine diagram of a tap controller in accordance with the present invention.

7 is an internal memory block diagram in accordance with the present invention.

* Description of the main parts of the drawing

10-22: input / output pad 23-35: boundary scan cell

40: application logic section

50: boundary scan test circuit

100: boundary scan register 110: device identification register

120: user test data register 130: bypass register

140: test data registers 150: instruction register

160: tap controller 170: decoding logic

180,190: Multiplexer

The present invention for achieving the above object includes an internal memory block, the apparatus for testing the internal memory block in a semiconductor chip that supports a boundary scan IEEE 1149.1 standard, the instructions for testing the internal memory block is added And a control register for storing control signals and data for testing the internal memory block in a user test data register.

It also includes a boundary test circuitry that supports an internal memory block and a boundary scan IEEE 1149.1 standard and includes a tap controller, a control register defined in a user test data register to store control signals and data for testing the internal memory block. A method for testing the internal memory block in a semiconductor chip, comprising: a first step of bringing a boundary test circuit into a reset state for initialization; A second step of moving to the Run-test / Idle state of the tap controller; Moving to the Select-DR-Scan state of the tap controller; A fourth step of writing a command for testing the internal memory in an instruction register of the boundary test circuit unit and then moving to a run-test / Idle state; A fifth step of moving to the Select-DR-Scan state of the tap controller; A sixth step of writing data and control signals that can be written to the internal memory to the control register for the internal memory test, and then moving to a run-test / Idle state to perform the internal memory write operation; A seventh step of moving to the Select-DR-Scan state of the tap controller; An eighth step of writing the information capable of reading the internal memory to the control register and moving to a run-test / Idle state to perform the internal memory read operation; A ninth step of moving to the Select-DR-Scan state of the tap controller; Read and compare the read data of the internal memory by using a scan chain, and at the same time, write information to read / write the internal memory of the next item in the control register and then move to the Run-test / Idle state. A tenth step of performing the internal memory read / write of a next item; An eleventh step of moving to the Select-DR-Scan state of the tap controller; And a twelfth step of writing a command to be executed next in the command register after the desired memory test is finished or ending a boundary scan operation and then moving to a next run-test / Idle state.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In recent semiconductor chip designs, a scan chain is inserted to increase fault coverage to increase controllability and observability, and to facilitate testing on board. Designed by adding logic to help test the board inside the chip, the standard for this logic is defined as JTAG Boundary Scan and Institute of Electrical and Electronic Engineers (IEEE) 1149.1 (hereafter BS 1149.1).

1 is a chip architecture implementing BS1149.1. Input / output pads 10 to 22 in charge of input / output of the chip, pads for receiving test data input signals (Test Data In, hereinafter referred to as TDI) for boundary scan, and test mode selection signals for boundary scan ( Pad to receive Test Mode Select, hereinafter referred to as TMS, Pad to receive test clock signal (Test Clock, hereinafter referred to as TCK) for boundary scan, and Test Reset signal (Test Reset, hereinafter referred to as TRST) for boundary scan A plurality of boundary scan cells (23 to 35) respectively connected to a pad for receiving an input, a pad for outputting a test data output signal (Test Data Out, hereinafter referred to as TDO) for a boundary scan, and an input / output pad. ), The application logic unit 40 connected to each boundary scan cell and the TDI pad to perform the function of the corresponding chip, and the signals output through the TDI, TMS, TCK, TRST and the application logic unit 40 are received.By outputting the TDO signal is made of the BS test circuit section 50 in charge of the test of the application logic section (40). The plurality of boundary scan cells 23 to 35 are chained, that is, the first boundary scan cell 23 is connected to the TDI pad, and the remaining boundary scan cells are each connected in series to the previous scan cell so that the last boundary scan cell ( 35 is connected to the BS test circuit section 50.

The present invention is to test the memory in the chip using the BS1149.1 architecture as shown in Figure 1, for this purpose a new instruction and BS test circuit for testing the internal memory in addition to the standard instructions proposed by BS 1149.1 There is a need for a register within 50 to read and write memory.

FIG. 2 is an internal block diagram of a BS test circuit unit, and includes a boundary scan register 100, a device identification register 110, and a user test data register, each receiving a TDI signal. A test data register 140 including a 120 and a bypass register 130, a command register 150 for receiving a TDI signal and storing a test command, and a test data register in response to the TCK, TMS, and TRST signals. After receiving a command from the tap controller (TAP, Test Access Port, 160) and the command register 150 that outputs the clock signal and the control signal of the 140 and the clock signal and the control signal of the command register 150, Decoding logic 170 for outputting to each register constituting the test data register 140, the test data register in response to the decoding result The output signal and the command from the first multiplexer 180 in response to the first multiplexer 180 and the select signal output from the tap controller 160. Triple buffer for outputting the second multiplexer 190 and one of the output signals from the register and the output signal from the second multiplexer to the TDO in response to the enable signal output from the tap controller 160. It consists of 200. The detailed description of the operation of the BS test circuit unit having such a configuration is well known as a standard, and thus the detailed description thereof is omitted here.

Here, the user test data register 120 is a register that can be defined by a user according to convenience of use, and defines a register necessary for the internal memory test of the present invention to perform a read / write operation on the internal memory.

FIG. 3 conceptually illustrates a control register of the present invention defined in a user test data register for controlling an internal memory, assuming that the internal memory to be tested is a set associative cache. It is. It is connected in series with the control unit 300 and the control unit 300 that receives a scan input (SI) and outputs a plurality of control signals to the internal memory, and receives the data read from the internal memory and outputs it to the SO It consists of 310. In this case, SI is a TDI signal, and SO is a signal output to the TDO through the first multiplexer 180 and the second multiplexer 190 of FIG. 2.

As described above, the register configuration of the present invention defined in the user test data register for the internal memory test is connected to the control unit 300 in front of the data unit 310 to scan the scan cycle used to test the internal memory. Can be reduced. That is, first, control signals and data input through the TDI are stored in the control register through the scan chain, in which only the control cycle is performed without performing the scan cycle until the end of the register, and then the internal memory read. When the memory data portion is read after the operation, the scan cycle can be reduced by only the data portion. 4A to 4B show internal configurations of the control unit and the data unit, respectively.

FIG. 4A illustrates an internal configuration of a control unit. When a cache page size is assumed to be 4K bytes, a 64-bit data field for storing memory data for writing to internal memory, and a tag of an internal memory. Tag & Index field for storing address (tag address, 20 bit) and index address (7 bit), LRU (Last Recently Used, 3 bit) field for write operation, State for write operation State field (2 bits) that stores bits, Way field (2 bits) that stores way selection bits for selecting one of four ways, and some of them because there are many bits per line Word field (2 bits) for reading the line by selecting and reading multiple times, control mode selection field (2 bits) for storing the control mode selection bits, and test read / write operation Made of an enable signal for enabling a test enable field for storing. The 2-bit control mode selection bit indicates no operation when "0", a test write when "1", a test read when "10", and a cache memory flush when "11".

Fig. 4B shows the internal configuration of the data portion, which is a 64-bit data field for storing data read from the internal memory, a tag field for storing a tag address (20 bit) read from the internal memory, and an eld read from the internal memory. An ELU (3-bit) field for storing the ALU bits and a state field (2 bits) for storing the state bits read from the internal memory.

Next, the control register of the present invention consists of cells of different structures, respectively, for convenience of control and data. FIG. 5A illustrates a cell constituting the control unit, and in response to shiftDR, a signal output from the multiplexer 500 and the multiplexer 500 which selects and outputs one of an SI signal and a feedback SO signal input through TDI. A reset operation is performed in response to the first flip-flops (DFF, 510) and the RESETb signal, which are received at the rising edge of the clockDR and output as an SO signal, and are output from the first flip-flop (510). A second flip-flop (DFF, 520) receives the SO signal from the rising edge of updateDR and stores it as a control signal (a plurality of control signals except for the data of FIG. 4A).

FIG. 5B illustrates a cell constituting a data unit. The multiplexer 530 and the multiplexer 530 which select and output one of an SI signal input through TDI and data read from an internal memory in response to shiftDR. ) Is a first flip-flop (DFF, 540) which receives the signal output from the Rx at the rising edge of the clockDR and outputs the SO signal.

Here, shiftDR (shift data register), clockDR (clock data register), updateDR (update data register) and RESETb are clock signals and control of the test data register 140 in response to the TCK, TMS and TRST signals of FIG. Signals and signals generated and output by the tap controller for outputting the clock signal and the control signal of the instruction register 150, the specific circuit of the tap controller is well known as a standard, so a detailed description thereof will be omitted.

The cells constituting the control unit of FIG. 5A store control signals for controlling the internal memory, and the cells constituting the data unit of FIG. 5B store data read from the internal memory. That is, by using five signals (TCK, TMS, TRST, TDI, TDO) provided as an external standard, the control unit of the control register is sequentially written, and then the internal memory is read or written. At the time of reading, the contents of the internal memory are loaded into the data portion of the control register and then read sequentially. At this time, a state machine for the tap controller is used, which is controlled by external control signals TRST, TMS, and TCK. 6 shows a detailed state machine for the tap controller. Here, a detailed description of each state is omitted since it is widely known as a standard, and with reference to the tap controller state machine of FIG. 6, the procedure for testing the internal memory is reset to initialize the boundary test circuit unit (50 in FIG. 1). The first step to make the state, the second step to go to the Run-test / Idle state of the tap controller, the third step to go to the Select-DR-Scan state of the tap controller, the instruction register of the boundary test circuit (150 in FIG. 2) Write the command to test the internal memory and move to the Run-test / Idle state, the fifth step to the Select-DR-Scan state of the tap controller, and write to the internal memory for the internal memory test. Data and control signals can be written to the user test data register (control register, 120 in Fig. 2) and then moved to the Run-test / Idle state. The sixth step of performing the memory write operation, the seventh step of moving to the Select-DR-Scan state of the tap controller, the run-test after writing the information to read the internal memory to the user test data register (control register) In the eighth step of moving to the / Idle state to perform the internal memory read operation, the ninth step of moving to the Select-DR-Scan state of the tap controller, and reading and comparing the data of the read-in internal memory using a scan chain, At the same time, after writing information that can read / write the internal memory of the next item to the internal control register, it moves to the Run-test / Idle state to perform the internal memory read / write of the next item. Command to be next executed in the instruction register (150 in FIG. 2) of the boundary test circuit part after the eleventh step of moving to the DR-Scan state and the desired memory test is finished. Light, or to end the boundary-scan operation then comprises a step 12 to move to the Run-test / Idle state.

In order to test the memory inside the chip using the boundary scan as described above, the internal memory block is configured by adding a multiplexer for selecting a control signal coming from the control register as shown in FIG. 7. That is, the normal memory control signal, the normal address, the normal data and the boundary scan control signal, the boundary scan address, and the boundary scan input from the user test data register in the normal data and the internal memory test operation instead of the memory test operation. Selection means for selecting from the data and sending it to the internal memory block is added.

Although the technical spirit of the present invention has been described in detail according to the above-described preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

According to the present invention as described above, by using a boundary scan to test the memory inside the chip, a separate pad is not required, and the control is simple, so that efficient testing of the internal memory is possible.

Claims (6)

An apparatus for testing an internal memory block on a semiconductor chip that includes an internal memory block and supports a boundary scan Institute of Electrical and Electronic Engineers (IEEE) 1149.1 standard, And a control register configured to add an instruction for testing the internal memory block and to store a control signal and data for testing the internal memory block in a user test data register. The method of claim 1, The control register, First storage means for receiving a scan input signal and outputting data for test and a plurality of control signals to the internal memory block; And Second storage means connected in series with the first storage means and receiving data and control signals read from the internal memory block and outputting them as scan output signals; Internal memory test device comprising a. The method of claim 2, The first storage means, When the internal memory is a cache consisting of a plurality of ways A data field for storing memory data for writing to the internal memory; A tag & index field for storing a tag address and an index address of the internal memory; An EL oil field for the write operation; A state field for storing a state bit for the write operation; A way field for storing a way select bit; Word field; A control mode selection field for storing a control mode selection bit; And Test enable field to store enable signal to enable test lead / write behavior Internal memory test device comprising a. The method of claim 3, wherein The control mode selection field is composed of 2 bits. When the bit value is "0", the control mode selection field has no operation, a test write when "1", a test lead when "10", and a cache memory flush when "11". Internal memory test apparatus, characterized in that each. The method of claim 2, The second storage means, When the internal memory is a cache consisting of a plurality of ways A data field for storing data read from the internal memory; A tag field for storing a tag address read from the internal memory; An LDL field storing an LDL bit read from the internal memory; And State field for storing state bits read from the internal memory Internal memory test device comprising a. An internal memory block, and Boundary scan A boundary test circuit that supports the IEEE 1149.1 standard and includes a control register defined in the user test data register to store a control signal and data for testing a tap controller and the internal memory block. In the method for testing the internal memory block in a semiconductor chip comprising a, A first step of putting into a reset state for initialization of the boundary test circuit; A second step of moving to the Run-test / Idle state of the tap controller; Moving to the Select-DR-Scan state of the tap controller; A fourth step of writing a command for testing the internal memory in an instruction register of the boundary test circuit and then moving to a run-test / Idle state; A fifth step of moving to the Select-DR-Scan state of the tap controller; A sixth step of writing data and control signals that can be written to the internal memory to the control register for the internal memory test, and then moving to a run-test / Idle state to perform the internal memory write operation; A seventh step of moving to the Select-DR-Scan state of the tap controller; An eighth step of writing the information capable of reading the internal memory to the control register and moving to a run-test / Idle state to perform the internal memory read operation; A ninth step of moving to the Select-DR-Scan state of the tap controller; Read and compare the read data of the internal memory by using a scan chain, and at the same time, write information to read / write the internal memory of the next item in the control register and then move to the Run-test / Idle state. A tenth step of performing the internal memory read / write of a next item; An eleventh step of moving to the Select-DR-Scan state of the tap controller; And Step 12 of writing a command to be executed next to the command register after the desired memory test is finished or ending a boundary scan operation and moving to the next run-test / idle state Internal memory test method comprising a.