Detection Method for Reusing Chip PADs

Abstract

The present invention discloses a detection method for multiplexing chip PADs, which is used to detect whether a chip enters a test mode, and includes the following steps: a. Reset the chip system to clear the test mode signal or the normal function operation mode signal of the chip; b. Detect the waveform parameters of the input signal of any one PAD to determine whether the chip enters the test mode; c. Determine the specific test items of the chip according to the input signals of the remaining PADs; d. Enter the specific test items and start the test process. The detection method for multiplexing chip PADs of the present invention can enable the chip to enter the test mode from the normal function operation mode and perform test operations without adding new test PDAs, realizing the multiplexing of chip PDAs, reducing the occupied area of the chip, and being more conducive to the integrated development of the chip.

Description

Technical Field

[0001] The present invention relates to the field of digital testing, and more specifically to a testing method for a multiplexed chip PAD. Background Art

[0002] During the application of integrated circuit chips, the chips are usually put into different modes according to different application scenarios, such as test mode and non-test mode (normal use mode of the chip).

[0003] How to make the same chip take into account both normal use mode and test mode? The existing technology usually uses the following two methods: Method 1, add a new test PAD on the chip, when it is necessary to enter the test mode, input a valid signal at the test PAD end to enter the test enable; Method 2, multiplex the function PAD, input waveforms with different frequencies and different duty cycles at the PAD end, and enter different test enables through waveform detection logic.

[0004] However, the above two methods have the following problems: In method 1, a new test PAD needs to be added, which increases the area of ​​the system chip; in method 2, when there are multiple test enables, the detection logic needs to detect waveforms of multiple frequencies and different duty cycles, which increases the design difficulty; at the same time, the PAD is a multiplexed PAD, and in normal functional mode (non-test mode), it may detect a waveform that is the same as the test enable, causing the system to mistakenly enter the test enable, resulting in failure to work normally.

[0005] Therefore, it is necessary to provide an improved detection method for multiplexed chip PAD to overcome the above defects. Summary of the invention

[0006] The purpose of the present invention is to provide a detection method for a multiplexed chip PAD. The detection method for a multiplexed chip PAD of the present invention can enable the chip to enter a test mode from a normal functional operation mode and perform a test operation without adding a new test PDA, thereby realizing the reuse of the chip PDA, reducing the occupied area of ​​the chip, and being more conducive to the integrated development of the chip.

[0007] To achieve the above object, the present invention provides a detection method for a multiplexed chip PAD, which is used to detect whether the chip enters a test mode, and comprises the following steps:

[0008] a. Chip system reset, clear the chip test mode signal or normal function operation mode signal;

[0009] b. Detect the waveform parameters of the input signal of any PAD to determine that the chip enters the test mode;

[0010] c. Determine the specific test items of the chip based on the input signals of the remaining PADs;

[0011] d. Enter the specific test item and start the test process.

[0012] Preferably, in the step a, the period of the system reset signal is widened to different extents to obtain the detection module reset signal and the function module reset signal.

[0013] Preferably, the period of the detection module reset signal is less than the period of the function module reset signal.

[0014] Preferably, the waveform parameters of the PAD input signal include waveform frequency, duty cycle, and number of cycles.

[0015] Preferably, in the step b, after the time when the system reset signal is set high reaches t1, the waveform parameters of the input signal of any one PAD are detected; t1 is the period difference between the test module reset signal and the system reset signal.

[0016] Preferably, in the step c, when the detection module detects the test signal input by the PAD after time t2, the test enable signal is made valid and the test process is started; t2 is the period difference between the test enable signal and the detection module reset signal.

[0017] Preferably, in the step c, the specific test mode enable signal is set high within the time t3 after the test enable signal is set high, and remains in the set high state after being set high. And when the time when the test enable signal is set high reaches t3, the chip enters the test of the specific item and releases the test multiplexing function of the current PAD; t3 is the period difference between the test enable signal and the function reset signal.

[0018] Preferably, in the step b, when the waveform parameters of the input signal of any one PAD do not meet the set conditions, the entire chip enters the non-test mode.

[0019] Compared with the prior art, the detection method of the PAD of the multiplexing chip of the present invention does not require an additional test PAD. The non-test (normal function operation) PAD of the multiplexing chip can enable the chip to enter the test mode and perform tests. Moreover, only by detecting the waveform parameters of the input signal of any one PAD, it can be determined whether to enter the test mode, which simplifies the test mode detection logic. In the present invention, the test mode and the normal function operation mode (non-test mode) are split in time into two stages, which can prevent system misjudgment and ensure that the conversion from the normal function operation mode to the test mode can be carried out correctly and accurately.

[0020] Through the following description and in combination with the accompanying drawings, the present invention will become clearer. These drawings are used to explain the embodiments of the present invention. Description of the Drawings

[0021] Figure 1 This is a flowchart of the detection method for the PAD of the multiplexing chip of the present invention.

[0022] Figure 2 This is a timing diagram during the detection process of the detection method for the PAD of the multiplexing chip of the present invention. Specific embodiments

[0023] Now, embodiments of the present invention will be described with reference to the accompanying drawings, in which like reference numerals represent like elements. As described above, the present invention provides a detection method for the PAD of a multiplexing chip. The detection method for the PAD of the multiplexing chip of the present invention can enable the chip to enter the test mode from the normal functional operation mode and perform test operations without adding a new test PDA, realizing the multiplexing of the chip PDA, reducing the occupied area of the chip, and being more conducive to the integrated development of the chip.

[0024] Please refer to Figure 1 , Figure 1 This is a flowchart of the detection method for the PAD of the multiplexing chip of the present invention. As Figure 1 shown, the detection method for the PAD of the multiplexing chip of the present invention, used to detect whether the chip enters the test mode, includes the following steps:

[0025] Step S001, the chip system is reset to clear the test mode signal and the normal functional operation mode signal of the chip. In this step, by clearing the test mode signal and the normal functional operation mode signal that may originally exist on the chip, interference to the subsequent detection process can be avoided; in addition, please also refer to Figure 2 , in this step, the period of the system reset signal rstn is widened to different degrees to obtain the detection module reset signal dest_rstn and the function module reset signal func_rstn; wherein, the period of the detection module reset signal dest_rstn is less than the period of the function module reset signal func_rstn, that is, the detection module reset signal dest_rstn will be pulled high (valid) prior to the function module reset signal func_rstn. Thus, in the present invention, by setting different periods of the detection module reset signal dest_rstn and the function module reset signal func_rstn, it is possible to first detect whether a test is to be performed and then specifically execute the function mode (i.e., the test mode or the normal functional operation mode), so as to ensure that the chip can operate in sequence in different modes without system misjudgment.

[0026] Step S002, detect the waveform parameters of the input signal of a specified PAD to determine that the chip enters the test mode; in this step, specifically, when the time for the system reset signal rstn to be set high reaches t1, detect a specified PAD (such as Figure 2As shown, the waveform parameters of the input signal of PAD_A are detected in the present invention. As is well known, multiple PADs are usually provided on a chip. For example, in the present invention, there are three PADs, namely PAD_A, PAD_B, and PAD_C. Of course, in practice, it is not limited to this. Here, it is only for convenience of description. In the solution of the present invention, only one specified PAD on the chip needs to be detected to accurately determine whether the chip enters the test mode, which simplifies the test mode detection logic, makes the detection method of the present invention easier to implement, and has lower costs. The specified PAD can be pre-designed by the designer according to the detection requirements, and there are no specific requirements. Among them, in the present invention, the waveform parameters of the PAD input signal include waveform frequency, duty cycle, and number of cycles. These waveform parameters can be flexibly set according to the detection requirements of different chips and specific condition parameters. For example, when the waveform frequency of the PAD input signal being detected is 500KHZ, the duty cycle is 30%, and the number of cycles is 16, it is determined that the chip enters the test mode. Of course, in practical applications, it is not limited to this method. In addition, in the present invention, t1 is the period difference between the test module reset signal dest_rstn and the system reset signal rstn. Obviously, the test module reset signal dest_rstn is obtained by broadening the system reset signal rstn, and its period is significantly longer than that of the system reset signal rstn. Therefore, the time when the test module reset signal dest_rstn is pulled high is later than that of the system reset signal rstn. That is, even if the system reset signal rstn is pulled high, the entire system is still in the reset stage before the test module reset signal dest_rstn is pulled high, ensuring that the detection process is strictly carried out according to the timing. In addition, as a preferred embodiment of the present invention, in this step, when the waveform parameters of the input signal of any one PAD do not meet the set conditions, the entire chip enters the non-test mode, that is, the normal function operation mode. At this time, there is no need to multiplex the PAD, and the chip can be used normally.

[0027] Step S003: Determine the specific test items of the chip according to the input signals of the remaining PADs. In this step, the combined input signals of all PADs on the chip constitute a complete input data signal. By detecting the specific waveform of the input signal of one PAD through the above steps to determine the entry into the test mode, after entering the test mode, it is necessary to combine the detection of the input signals of the other remaining PADs (such as the two PADs, PAD_B and PAD_C, set in the present invention) to determine the specific test items of the chip. In addition, in the present invention, when the detection module detects the test signal input by the PAD after time t2, the test enable signal test_mode becomes valid and the test process is started (such as Figure 2As shown); t2 is the period difference between the test enable signal test_mode and the detection module reset signal dest_rstn, that is, within time t2 (within t2 after the detection module reset signal dest_rstn is pulled high), the detection module detects the signal input by PAD_A and determines to enter the test mode within this time, and then makes the test enable signal valid, so setting the time interval t2 can ensure that the signal input by PAD_A is detected and ensures that the test mode can be entered accurately. Furthermore, in this step, the specific test mode enable signal testx_mode is set high within the time t3 after the test enable signal test_mode is set high, and remains in the high state after being set high, and when the test enable signal test_mode is set high for a time period of t3, the chip enters the test of the specific project and releases the test multiplexing function of the current PAD; t3 is the period difference between the test enable signal test_mode and the function module reset signal func_rstn; within the time t3 when the test enable signal test_mode is set high, the detection module detects the input signals of other PADs other than those detected in step S002, and then determines the specific project to be tested later; thereby setting t3. A time interval can ensure that the detection of signals of all other PAD inputs is completed, and it is guaranteed that the specific test items can be entered accurately; from the above, it can be seen that within the time t3, the specific test mode enable signal testx_mode is set high, that is, the specific test mode enable signal testx_mode and the test enable signal test_mode may both be set high within the time t3, but because within the time t3, the function module reset signal func_rstn is always in the reset state, so the test of the specific item will not be started at this time, and the specific test will only be started after the function module reset signal func_rstn and the specific test mode enable signal testx_mode are both set high after the time t3.

[0028] Step S004, enter the specific test item and start the test process; in this step, through the detection of the above steps, it has been determined to enter the test mode, and the specific test items have been determined, and all test preparations have been completed. Enter the specific test item and start the test process according to the set requirements.

[0029] In summary, the detection method of the multiplexing chip PAD of the present invention does not require additional test PADs. The non-test (normal function operation) PADs of the multiplexing chip can enable the chip to enter the test mode and perform tests. Moreover, by only detecting the waveform parameters of the input signal of any one PAD, it can be determined whether to enter the test mode, which simplifies the test mode detection logic. In the present invention, the test mode and the normal function operation mode (non-test mode) are split in time into two stages, which can prevent system misjudgment and ensure that the conversion from the normal function operation mode to the test mode can be carried out correctly and accurately.

[0030] The present invention has been described in conjunction with the best embodiments, but the present invention is not limited to the disclosed embodiments above, and should cover various modifications and equivalent combinations made according to the essence of the present invention.

Claims

1. A detection method for multiplexing chip PADs, used to detect whether the chip enters the test mode, characterized in that, It includes the following steps: a. Reset the chip system to clear the test mode signal and normal function operation mode signal of the chip; b. Detect the waveform parameters of the input signal of a specified PAD to determine that the chip enters the test mode; c. Determine the specific test items of the chip according to the input signals of the remaining PADs; d. Enter the specific test item and start the test process; Among them, in the step a, the period of the system reset signal is widened to different degrees to obtain the detection module reset signal and the function module reset signal, and the period of the detection module reset signal is less than the period of the function module reset signal.

2. The detection method of the PAD of the multiplexing chip according to claim 1, characterized in that, The waveform parameters of the PAD input signal include waveform frequency, duty cycle and number of cycles.

3. The detection method of the multiplexing chip PAD according to claim 1, wherein, In the step b, when the time when the system reset signal is set high reaches t1, detect the waveform parameters of the input signal of any one PAD; t1 is the period difference between the test module reset signal and the system reset signal.

4. The detection method of the multiplexing chip PAD according to claim 3, characterized in that, In the step c, when the detection module detects the test signal input by the PAD after time t2, make the test enable signal valid and start the test process; t2 is the period difference between the test enable signal and the detection module reset signal.

5. The detection method of the multiplexing chip PAD according to claim 4, characterized in that, In the step c, the specific test mode enable signal is set high within the time t3 after the test enable signal is set high, and remains set high after being set high. And when the time when the test enable signal is set high reaches t3, the chip enters the test of specific items and releases the test multiplexing function of the current PAD; t3 is the period difference between the test enable signal and the function reset signal.

6. The detection method of the multiplexing chip PAD according to claim 3, wherein, In the step b, when the waveform parameters of the input signal of any one PAD do not meet the set conditions, the entire chip enters the non-test mode.

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