JTAG-SMT2-NC does not work properly and cannot find JTAG device

yixiti · June 4, 2018

I hope the factory technical support staff can answer it, thank you

WINDOWS Device Manager Phenomenon:

1.png.5187af9d474e6432b670623eb048dbfd.png

After connecting the JTAG module to the computer, the USB device can only be found in the hardware manager, and the JTAG device cannot be found. Only one USB serial converter can be found as shown in the figure.

In the management menu of WIN10, you can see other devices displaying DIGILENT USB DEVICE, as shown

2.png.0af6057b1a37097bd3828eb60f4ef84e.png

Under normal circumstances, a COM serial port will be displayed in the WIN7 device manager, but the damaged module cannot find the COM serial port in the WIN7 computer management.

VIVADO phenomenon:

Damaged Modules Using VIVADO Connections in WIN7 Scan to XILINX_TCF/DIGILENT/...

But can't connect as shown

33.JPG.dc42246ff43cf5df78db52ee45b3f6df.JPG

After the module is replaced, the problem persists. If the damaged module is removed and USB is connected separately and the power is supplied, the device cannot be recognized. However, a short-time serial port can be automatically scanned in VIVADO. Using a backup scheme on the board, which uses an external JTAG scanning device connection to connect to the FPGA, the FPGA's JTAG chain is undamaged. Related drawings are shown below.

44.JPG.2be82258adec2e6368ae79094319d678.JPG

DIGILENT ADPET scanning phenomenon:

Using the DIGILENT ADPET scan can scan the device model of the damaged module, but no data can be scanned as shown in the figure:

5.png.3f6c3e87ac0387986b286d483f56adf2.png

The log is as follows:

Loading board information...

Warning: Could not find specific board information

Initializing Scan Chain...

Default information loaded.

Found device ID: ffffffff

Initialization Failed.

However, the SN of the device can be scanned in the DEVICE MANAGER. as the picture shows

6.png.09b00f4aaf2555f63e091e8f4e5b19d3.png

In the normally used board of the JTAG-SMT2-NC module, although the COM serial port is not visible in the WIN10 device manager, the device can be scanned using ADEPT as shown in the figure.

7.png.998c80db95ceb3fedd4b52f11c119ebb.png

The circuit diagram related to the module and module is as follows

Which TDO from V7 after the level conversion chip is not actually connected in series 50OHM resistor directly to the module's TDO pin, suspected of causing problems after the TDO level conversion chip was replaced to prevent the TDO at the level The push-pull output of the converter chip causes damage to the JTAG module. An N-channel MOS transistor is used for level shifting. Both voltage sides are pulled up using 15K resistors, and then the new JTAG module is replaced, but the problem remains. Replacement level conversion chip circuit as shown, this circuit can make both voltage side signals are weak pull-up state.

MOS tube using BSS138, 1.8V pressure difference can meet the GS open voltage requirements.

In addition, this JTAG module is not damaged at the beginning of a power-on, but it can be used just after the DCB is completed, but it is unstable. After a few days, the JTAG module cannot be connected to the FPGA. After connecting the jumper cap in the above circuit diagram Using the reserved 6PIN pin to connect the external JTAG module can debug the FPGA normally, but it cannot be connected normally after replacing the JTAG-SMT2-NC module.

JColvin · June 6, 2018

Hi @yixiti,

I would like to clarify some things so that I can make sure that I am properly understanding the situation.

-You have two separate JTAG SMT2 NC's that you are showing in your post; one that is working and one that is not, correct?

-The non-working JTAG SMT2 NC only shows up in device manager as a Serial Converter and not as a COM port and cannot be programmed in Vivado or successfully recognized by Adept. If you switch the non-working JTAG SMT2 NC for the working JTAG SMT2 NC, Vivado continues to have issues detecting the FPGA, though you can detect the FPGA through a separate JTAG setup.

-When using Adept, the non-working JTAG SMT2 NC fails to initialize the chain, though you can detect the serial number of the device in the DPCOMM Device Table Manager.

- If you switch to the working JTAG SMT2 NC, Adept can initialize the chain, and recognize and program all of the detected devices, correct?

- Is there a chance you can use some sort of screen capture for the pictures you took of your schematic, such as using Windows snipping tool or something similar? I am having difficultly reading the images of the computer screen.

Thank you,
JColvin

yixiti · June 6, 2018

2 hours ago, JColvin said:

Hi @yixiti,

I would like to clarify some things so that I can make sure that I am properly understanding the situation.

-You have two separate JTAG SMT2 NC's that you are showing in your post; one that is working and one that is not, correct?

-The non-working JTAG SMT2 NC only shows up in device manager as a Serial Converter and not as a COM port and cannot be programmed in Vivado or successfully recognized by Adept. If you switch the non-working JTAG SMT2 NC for the working JTAG SMT2 NC, Vivado continues to have issues detecting the FPGA, though you can detect the FPGA through a separate JTAG setup.

-When using Adept, the non-working JTAG SMT2 NC fails to initialize the chain, though you can detect the serial number of the device in the DPCOMM Device Table Manager.

- If you switch to the working JTAG SMT2 NC, Adept can initialize the chain, and recognize and program all of the detected devices, correct?

- Is there a chance you can use some sort of screen capture for the pictures you took of your schematic, such as using Windows snipping tool or something similar? I am having difficultly reading the images of the computer screen.

Thank you,
JColvin

Hi @JColvin

The problem has been solved. The reason for the problem is that the partial pressure of the TMS signal cannot be lowered.

Thank you very much.

yixiti

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JTAG-SMT2-NC does not work properly and cannot find JTAG device

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