UPGRADE YOUR BROWSER

We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

cancel
Showing results for 
Search instead for 
Did you mean: 
Highlighted
Visitor stefuni
Visitor
4,549 Views
Registered: ‎09-19-2014

Zynq: UART use modem control RTS/CTS only

Jump to solution

Hi,

 

I'm new to Zynq (did some spartan-3 in the past) and have a problem that must have occured before but I can't find anything on the subject.

 

I managed to get the UART0 signals on the EMIO interface and connect RXD and TXD to IO pins. Now I want to add RTS/CTS and have added "modem" lines to EMIO. But this includes all modem lines, not just RTS/CTS. If I just assign RTS/CTS to pins and leave the others default I get errors during bitstream generation:

 

ERROR: [Drc 23-20] Rule violation (NSTD-1) Unspecified I/O Standard - 4 out of 138 logical ports ...

ERROR: [Drc 23-20] Rule violation (UCIO-1) Unconstrained Logical Port - 4 out of 138 logical ports ...

 

How to only connect specified modem lines to EMIO and IO pins?

 

I'm using a MicroZed board and Vivado 2014.2

 

Regards,

 

Stef

 

0 Kudos
1 Solution

Accepted Solutions
Visitor stefuni
Visitor
6,287 Views
Registered: ‎09-19-2014

Re: Zynq: UART use modem control RTS/CTS only

Jump to solution

Okay, I have found a solution in the mean time:

-Expand the UART0 bus

- Connect the signals you want

- Tie up any left over inputs to a constant

 

See attached picture as well.

 

uart_part.png
0 Kudos
4 Replies
Xilinx Employee
Xilinx Employee
4,522 Views
Registered: ‎07-21-2014

Re: Zynq: UART use modem control RTS/CTS only

Jump to solution

 

Hi,

 

As you know that you are only using  RTS/CTS of modem, you can reduce this error to warning using following commands

 

set_property SEVERITY {Warning} [get_drc_checks NSTD-1]
set_property SEVERITY {Warning} [get_drc_checks UCIO-1]

 

this usually is not recommanded but in your case this will not cause any issue

 

hope this helps

 

thanks 

Shreyas

 

----------------------------------------------------------------------------------------------
Try to search answer for your issue in forums or xilinx user guides before you post a new thread.

Kindly note- Please mark the Answer as "Accept as solution" if information provided solves your query.
Give Kudos (star provided in left) to a post which you think is helpful and reply oriented.
----------------------------------------------------------------------------------------------

----------------------------------------------------------------------------------------------
Try to search answer for your issue in forums or xilinx user guides before you post a new thread.

Kindly note- Please mark the Answer as "Accept as solution" if information provided solves your query.
Give Kudos (star provided in right) to a post which you think is helpful and reply oriented.
----------------------------------------------------------------------------------------------
0 Kudos
Xilinx Employee
Xilinx Employee
4,513 Views
Registered: ‎01-03-2008

Re: Zynq: UART use modem control RTS/CTS only

Jump to solution

> this usually is not recommanded but in your case this will not cause any issue

 

This is not correct.  When the IO are not explicitly assigned both a location and IOSTANDARD it can create problems at the board level which is why this DRC exists.

 

Every I/O needs to be properly constrained to ensure a functioning design.

------Have you tried typing your question into Google? If not you should before posting.
Too many results? Try adding site:www.xilinx.com
0 Kudos
Visitor stefuni
Visitor
4,499 Views
Registered: ‎09-19-2014

Re: Zynq: UART use modem control RTS/CTS only

Jump to solution

Ok, so just ignoring the error is not a good option. Other problem with that solution is that it turns all errors of that kind into a warning, not just the ones about the intended signals.

 

But is there another solution to use only part of the modem lines of a uart? Can I for instances get them out of the 'bus' from the PS block and tie them up in the PL? How would I do this?

 

Same issue comes up with the SPI. If routed to the EMIO, it includes three SS signals where I need only one to go to a pin.

0 Kudos
Visitor stefuni
Visitor
6,288 Views
Registered: ‎09-19-2014

Re: Zynq: UART use modem control RTS/CTS only

Jump to solution

Okay, I have found a solution in the mean time:

-Expand the UART0 bus

- Connect the signals you want

- Tie up any left over inputs to a constant

 

See attached picture as well.

 

uart_part.png
0 Kudos