unused pins

Hello,

In my custom carrier card design I will leave several pins without using and I was wondering how to connect those pins: floating or grounding. Most of the pins are dedicated for signals but others are connected to specific nets which I have left floating according to the recommendations: 4 JTAG, CARRIER SRST, FPGA DONE, FPGA VBAT, 8 PMOD and INIT.

On the other hand, I also wondered whether it is possible to use the PUDC_B signal pin, which I am not going to use in my carrier card, as a signal pin. Although I have empty pins I want to complete the banks 34 and 35.

Thank you in advance

Víctor

0 jafoste4 over 8 years ago

Hello Victor,
With your unused signals I would suggest you pull them out to a pad incase later down the line you need access to them. So long as you do not set any of them as inputs you will not recieve any noise.
As for the PUDC_B signal pin make sure you do not allow this pin to float before and during configuration. To determine if it is dual use please refer to Xilinx supporting document UG865.
http://www.xilinx.com/support/documentation/user_guides/ug865-Zynq-7000-Pkg-Pinout.pdf
--Josh
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0 Former Member over 8 years ago in reply to jafoste4

Thanks Josh,

About pulling the unused signals out to a pad was my first idea so I will do it. What is an interesting point is your comment about no to set those pins as inputs to avoid any noise.

As for the PUDC_B signal pin, I am using it as an input, taking into account that the Microzed already has that signal pulled up, so in this way I consider I would not leave this pin (net) to float before and during configuration.

Regards

Víctor
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