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JTAG-SMT2-NC. GPIO behaviour


Question

Good afternoon.

 

We have several JTAG_SMT2-NC modules on some identical cards.

We have observed an anormal behaviour on GPIO2 pin. This pin are connected to PS_SRST_B pin of a Xilinx Zynq FPGA.

In good cards, when the card are power on, GPIO2 signal goes to high (3,3V) level. So the Zynq is not reset.

In some "bad" cards, GPIO2 signal goes to low level when the card are powered on.

 

It could be a JTAG_SMT2-NC FW or version issue?

Could I check JTAG_SMT2-NC version via current USB connection?

If not, could I send you JTAG_SMT2-NC serial number or address in order to get FW version.

 

Best regards,

 

D. Carrasco

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Hi @Daniel Carrasco,

Hmm. There isn't any firmware as such in the JTAG SMT2-NC (or any of the Digilent JTAG products).

I'm surprised to hear that on power-up the GPIO2 signal goes low because all of the GPIO pins on the JTAG SMT2-NC have an integrated pull-up resistor to ensure that the GPIO signals are not floating while be not being actively driven, as the case would be on power-up as Xilinx tools would not have control of the module immediately upon power-up: https://reference.digilentinc.com/reference/programmers/jtag-smt2-nc/reference-manual#gpio_pins. After Xilinx takes control of the device and enables DPIO port 0

With this, what I would be checking on your cards would be those pull-up resistors (R4 for this particular pin) and other sources to see what might be bringing this pin to a low state upon initial power up.

Thanks,
JColvin

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