JTAG detection and diagnosis device

Abstract

The utility model discloses a JTAG (Joint Test Action Group) detection and diagnosis device, which is used for respectively testing ground impedance and power supply impedance of four JTAG signals (TCK, TMS, TDI and TDO), testing impedance among the signals, measuring forward / reverse direction of characteristic voltage of a diode, measuring waveform characteristics when the JTAG is connected, comparing test measurement data with standard data and waveform, and giving out a judgment result that the JTAG works normally / abnormally. According to the scheme of the utility model, the JTAG troubleshooting efficiency can be improved.

Description

Technical Field

[0001] This utility model relates to the field of circuit testing technology, and in particular to a JTAG detection and diagnostic device. Background Technology

[0002] JTAG (Joint Test Action Group) is an international standard test protocol (IEEE 1149.1 compliant) primarily used for internal chip testing. Most advanced devices support the JTAG protocol, such as DSPs and FPGAs. A standard JTAG interface has four lines: TMS, TCK, TDI, and TDO, representing mode selection, clock, data input, and data output, respectively.

[0003] At the hardware level, a standard JTAG interface typically consists of four lines: TMS (Test Mode Select), TCK (Test Clock), TDI (Test Data Input), and TDO (Test Data Output). These lines are used to control the test mode, synchronize the clock, transmit data, and receive test results, respectively.

[0004] The connection method of the JTAG interface may vary depending on the device, such as ARM, DSP and FPGA.

[0005] In existing technologies, JTAG connection failures are frequently encountered during circuit board R&D and mass production (the main control chip is ARM, DSP, or FPGA), making troubleshooting time-consuming and labor-intensive. The troubleshooting process requires checking the main control chip's power supply, reset, clock, and critical configuration pins, which relies on manual inspection and is inefficient. Utility Model Content

[0006] This invention provides a JTAG detection and diagnostic device to solve the problem of low efficiency in JTAG circuit board detection in the prior art.

[0007] According to one aspect of the present invention, a JTAG detection and diagnostic device is provided, comprising:

[0008] The voltage test unit is used to test the voltage of each power supply of the main control chip on the PCB board under test to determine the power supply operating status.

[0009] The first relay array is used to switch the channels of the four JTAG signals TCK, TMS, TDI and TDO of the PCB under test and measure the impedance.

[0010] The second relay array is used to switch the channels of the four JTAG signals TCK, TMS, TDI and TDO of the PCB under test, and to measure the diode characteristics of the JTAG signals.

[0011] The third relay array is used to connect / disconnect the simulator for the four JTAG signals TCK, TMS, TDI and TDO of the PCB under test.

[0012] The JTAG signal and key signal acquisition board is used to acquire four JTAG signals TCK, TMS, TDI and TDO from the PCB board under test, and compare them with normal JTAG waveforms to mark the waveform differences.

[0013] The JTAG simulator is used to simulate and display the JTAG signals and the annotation results of the key signal acquisition board based on the control of the third relay array.

[0014] The device further includes:

[0015] Impedance test board, which includes 16 impedance test circuits, is connected to the first relay array to measure the impedance of four JTAG signals TCK, TMS, TDI and TDO of the PCB under test.

[0016] The impedance test board measures the impedance to ground, impedance to power supply, and short circuit between the four JTAG signals TCK, TMS, TDI, and TDO of the PCB under test. The impedance test range and accuracy can be adjusted as needed.

[0017] The impedance test plate includes:

[0018] Test the impedance to ground to determine if the JTAG signal is short-circuited to ground and locate the short-circuit fault.

[0019] Test the power supply impedance to determine if the JTAG signal is short-circuited to the power supply and locate the short-circuit fault.

[0020] Short circuit between each other, whether JTAG signals are short-circuited, short circuit fault between positioning signals.

[0021] The device further includes:

[0022] The diode reverse / forward test board is used to connect to the second relay array to switch the channels of the four JTAG signals TCK, TMS, TDI, and TDO on the PCB under test, and to measure the diode characteristics and small current signals of the JTAG signals.

[0023] The diode reverse / forward test board includes:

[0024] The differential amplifier circuit is used to test the diode characteristics directly on the JTAG pin. It uses a differential circuit with high impedance input. For small current signals, a high-precision sampling resistor is connected between Vin+ and Vin- to complete the I / V conversion.

[0025] Differential to single-ended circuit, used to convert differential signals into single-ended signals;

[0026] The DC bias circuit is used to increase the amplitude of the analog signal to near the median data of the ADC input, making it easier to test.

[0027] The differential amplifier circuit consists of operational amplifiers U1C and U1D, and resistors R1-R5, wherein...

[0028] Vin+ is connected to the non-inverting input of operational amplifier U1C through resistor R1; Vin- is connected to the inverting input of operational amplifier U1D through resistor R2; the inverting input of operational amplifier U1C and the non-inverting input of operational amplifier U1D are connected in series with resistor R4; the two ends of resistor R4 are connected to the outputs of operational amplifier U1C and U1D through resistors R3 and R5 respectively.

[0029] Resistors R1 and R2 are used as balancing input resistors, while resistors R3-R5 amplify the voltage; the amplification factor is G1, satisfying the following relationship:

[0030] V1+-V1-=G1(Vin+-Vin-)

[0031] Where G1 = (R3 + R4 + R5) / (R4).

[0032] The differential-to-single-ended circuit consists of operational amplifiers U1B and U1D, and resistors R6-R9. Its output satisfies the following relationship:

[0033] V2 = G2(Vin+ - Vin-)

[0034] Where G2 = 1.

[0035] The device further includes:

[0036] The power supply is used to provide power to the PCB board under test.

[0037] The device further includes:

[0038] The display terminal connects to the JTAG emulator and displays the software test interface and test results output by the JTAG emulator via software.

[0039] This invention proposes a JTAG detection and diagnostic scheme. It tests the impedance to ground and impedance to power supply (with the circuit board unpowered) for four JTAG signals (TCK, TMS, TDI, TDO), the impedance between the signals, the forward / reverse characteristic voltage of the diode, and the waveform characteristics when the JTAG is connected. The test data and standard data / waveforms are compared to determine whether the JTAG is functioning normally or abnormally. This invention improves the efficiency of JTAG fault diagnosis.

[0040] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0041] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0042] Figure 1 This is a schematic diagram of the JTAG detection and diagnostic device in an embodiment of the present invention;

[0043] Figure 2 This is a circuit diagram illustrating one implementation of the diode reverse / forward test board in this utility model embodiment. Detailed Implementation

[0044] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0045] The basic idea of ​​this utility model embodiment is as follows:

[0046] For the four JTAG signals (TCK, TMS, TDI, TDO), test the impedance to ground and the impedance to power supply (with the board not powered on).

[0047] For the four JTAG signals (TCK, TMS, TDI, TDO), the impedance between the signals;

[0048] For four JTAG signals (TCK, TMS, TDI, TDO), measure the diode characteristic voltage: forward / reverse.

[0049] For the four JTAG signals (TCK, TMS, TDI, TDO), measure the waveform characteristics when JTAG is connected.

[0050] On the host computer, the above data is compared with standard data and waveforms to determine whether JTAG is working normally or abnormally.

[0051] Figure 1 This is a schematic diagram of the JTAG detection and diagnostic device in an embodiment of this utility model. Figure 1 As shown, the JTAG detection and diagnostic device includes:

[0052] The voltage testing unit is used to test the voltage of each power supply of the main control chip on the PCB board under test to determine the power supply's operating status. It features a 12-bit ADC detection, typically including: 1.0V, 1.35V, 1.8V, 3.3V, and 5.0V.

[0053] Relay array 1 (first relay array) is used to switch the channels of the four JTAG signals TCK, TMS, TDI and TDO of the PCB under test and measure the impedance.

[0054] Impedance test board, which includes 16 impedance test circuits, connects to relay array 1 to measure the impedance of four JTAG signals TCK, TMS, TDI and TDO of the PCB under test.

[0055] The impedance test board measures the impedance to ground, impedance to power supply, and short circuit between the four JTAG signals TCK, TMS, TDI, and TDO of the PCB under test. The impedance test range and accuracy can be adjusted as needed.

[0056] Test the impedance to ground to determine if the JTAG signal is short-circuited to ground and locate the short-circuit fault.

[0057] Test the power supply impedance to determine if the JTAG signal is short-circuited to the power supply and locate the short-circuit fault.

[0058] Short circuit between each other, whether JTAG signals are short-circuited, short circuit fault between positioning signals.

[0059] The details are shown in the table below.

[0060]

[0061] Relay array 2 (second relay array) is used to switch the channels of the four JTAG signals TCK, TMS, TDI and TDO of the PCB under test, and to measure the diode characteristics of the JTAG signals.

[0062] The diode reverse / forward test board is used to connect to relay array 2 to switch the channels of the four JTAG signals TCK, TMS, TDI and TDO of the PCB under test, and measure the diode characteristics and small current signals of the JTAG signals.

[0063] Diode reverse / forward test board, including:

[0064] The differential amplifier circuit is used to test the diode characteristics directly on the JTAG pin. It uses a differential circuit with high impedance input. For small current signals, a high-precision sampling resistor is connected between Vin+ and Vin- to complete the I / V conversion.

[0065] Differential to single-ended circuit, used to convert differential signals into single-ended signals;

[0066] The DC bias circuit is used to increase the amplitude of the analog signal to near the median data of the ADC input, making it easier to test.

[0067] Specific circuit as follows Figure 2 As shown, where,

[0068] The entire circuit consists of a differential amplifier, a differential-to-single-ended converter, and a DC bias circuit.

[0069] Differential amplification:

[0070] (1) For diode characteristic testing, the test is performed directly on the JTAG pin. The input impedance is high, so a differential circuit with high impedance input is required.

[0071] (2) For small current signals, a high-precision sampling resistor is connected between Vin+ and Vin- to complete the I / V conversion.

[0072] The differential amplifier circuit consists of operational amplifiers U1C and U1D, and resistors R1-R5. Resistors R1 and R2 are used as balancing input resistors. Resistors R3-R5 amplify the voltage. The amplification factor is G1, satisfying the following relationship:

[0073] V1+-V1-=G1(Vin+-Vin-), where G1=(R3+R4+R5) / (R4)

[0074] The common-mode input circuit composed of operational amplifiers U1C and U1D has a high input impedance.

[0075] Differential to single-ended: Differential signals need to be converted into single-ended signals.

[0076] The differential amplifier circuit consists of operational amplifier U1B, operational amplifier U1D, and resistors R6-R9.

[0077] V2 = G2(Vin+-Vin-), where G2 = 1.

[0078] DC bias signal: Increases the amplitude of the analog signal to near the median data of the ADC input, making testing easier.

[0079] The DC bias circuit consists of operational amplifier U1A and resistors R10-R13, and satisfies the following relationship:

[0080] Vout = Vref + V2.

[0081] Relay array 3 (third relay array) is used to connect / disconnect the simulator for the four JTAG signals TCK, TMS, TDI and TDO of the PCB under test.

[0082] The JTAG signal and key signal acquisition board is used to acquire four JTAG signals (TCK, TMS, TDI, and TDO) from the PCB under test and compare them with normal JTAG waveforms, marking the waveform differences. The JTAG signals are all digital signals with frequencies below 10MHz, making them easy to acquire.

[0083] The device also includes:

[0084] The JTAG emulator is used to simulate and display the JTAG signals and the annotation results of the key signal acquisition board according to the control of relay array 3.

[0085] The power supply is used to provide power to the PCB board under test.

[0086] The display terminal connects to the JTAG emulator and displays the software test interface and test results output by the JTAG emulator via software.

[0087] In summary, the technical solution of this utility model proposes a JTAG detection and diagnosis scheme. It tests the impedance to ground and impedance to power supply for the four JTAG signals (TCK, TMS, TDI, TDO) respectively (with the circuit board not powered on), the impedance between the test signals, measures the forward / reverse characteristic voltage of the diode, and measures the waveform characteristics when the JTAG is connected. The test measurement data is compared with standard data and waveforms to provide a judgment result indicating whether the JTAG is working normally or abnormally. This utility model scheme can improve the efficiency of JTAG fault diagnosis.

[0088] Those skilled in the art will understand that embodiments of this invention can be provided as methods, systems, or computer program products. Therefore, this invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this invention can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0089] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing device, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0090] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0091] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0092] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A JTAG detection and diagnostic device, characterized in that, include: The voltage test unit is used to test the voltage of each power supply of the main control chip on the PCB board under test to determine the power supply operating status. The first relay array is used to switch the channels of the four JTAG signals TCK, TMS, TDI and TDO of the PCB under test and measure the impedance. The second relay array is used to switch the channels of the four JTAG signals TCK, TMS, TDI and TDO of the PCB under test, and to measure the diode characteristics of the JTAG signals. The third relay array is used to connect / disconnect the simulator for the four JTAG signals TCK, TMS, TDI and TDO of the PCB under test. The JTAG signal and key signal acquisition board is used to acquire four JTAG signals TCK, TMS, TDI and TDO from the PCB board under test, and compare them with normal JTAG waveforms to mark the waveform differences. The JTAG simulator is used to simulate and display the JTAG signals and the annotation results of the key signal acquisition board based on the control of the third relay array.

2. The JTAG detection and diagnostic device according to claim 1, characterized in that, The device further includes: Impedance test board, which includes 16 impedance test circuits, is connected to the first relay array to measure the impedance of four JTAG signals TCK, TMS, TDI and TDO of the PCB under test.

3. The JTAG detection and diagnostic device according to claim 2, characterized in that, The impedance test board measures the impedance to ground, impedance to power supply, and short circuit between the four JTAG signals TCK, TMS, TDI, and TDO of the PCB under test. The impedance test range and accuracy can be adjusted as needed.

4. The JTAG detection and diagnostic device according to claim 3, characterized in that, The impedance test plate includes: Test the impedance to ground to determine if the JTAG signal is short-circuited to ground and locate the short-circuit fault. Test the power supply impedance to determine if the JTAG signal is short-circuited to the power supply and locate the short-circuit fault. Short circuit between each other, whether JTAG signals are short-circuited, short circuit fault between positioning signals.

5. The JTAG detection and diagnostic device according to claim 1, characterized in that, The device further includes: The diode reverse / forward test board is used to connect to the second relay array to switch the channels of the four JTAG signals TCK, TMS, TDI, and TDO on the PCB under test, and to measure the diode characteristics and small current signals of the JTAG signals.

6. The JTAG detection and diagnostic device according to claim 5, characterized in that, The diode reverse / forward test board includes: The differential amplifier circuit is used to test the diode characteristics directly on the JTAG pin. It uses a differential circuit with high impedance input. For small current signals, a high-precision sampling resistor is connected between Vin+ and Vin- to complete the I / V conversion. Differential to single-ended circuit, used to convert differential signals into single-ended signals; The DC bias circuit is used to increase the amplitude of the analog signal to near the median data of the ADC input, making it easier to test.

7. A JTAG detection and diagnostic device according to claim 6, characterized in that, The differential amplifier circuit consists of operational amplifiers U1C and U1D, and resistors R1-R5, wherein... Vin+ is connected to the non-inverting input of operational amplifier U1C through resistor R1; Vin- is connected to the inverting input of operational amplifier U1D through resistor R2; the inverting input of operational amplifier U1C and the non-inverting input of operational amplifier U1D are connected in series with resistor R4; the two ends of resistor R4 are connected to the outputs of operational amplifier U1C and U1D through resistors R3 and R5 respectively. Resistors R1 and R2 are used as balancing input resistors, while resistors R3-R5 amplify the voltage; the amplification factor is G1, satisfying the following relationship: V1+-V1-=G1(Vin+-Vin-) Where G1 = (R3 + R4 + R5) / (R4).

8. A JTAG detection and diagnostic device according to claim 6, characterized in that, The differential-to-single-ended circuit consists of operational amplifiers U1B and U1D, and resistors R6-R9. Its output satisfies the following relationship: V2 = G2(Vin+ - Vin-) Where G2 = 1.

9. A JTAG detection and diagnostic device according to claim 1, characterized in that, The device further includes: The power supply is used to provide power to the PCB board under test.

10. A JTAG detection and diagnostic device according to claim 1, characterized in that, The device further includes: The display terminal connects to the JTAG emulator and displays the software test interface and test results output by the JTAG emulator via software.

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