cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 
sriramv90
Visitor
Visitor
12,354 Views
Registered: ‎07-30-2015

MIG PHY read data valid

Hi,

 

I'm using a MIG PHY only design with a custom controller. The design works mostly but crashes due to no read data valid signal from the PHY when there is a continuous read from the application. This crash varies between 10 to 50 reads. Please suggest as to why this behavior is seen. 

 

I'm using MIG 7 series with Vivado 2015.2 for Zynq ZC706 board. Please advise.

 

Thanks,

Sriram

0 Kudos
3 Replies
sriramv90
Visitor
Visitor
12,351 Views
Registered: ‎07-30-2015

Hi,  

 

After a bit of searching, we found that this could be due to missing periodic reads. Could anyone explain what periodic logic does and is it necessary for all phy only designs. Please advise. Thanks in advance.

 

-Sriram

0 Kudos
vsrunga
Xilinx Employee
Xilinx Employee
12,341 Views
Registered: ‎07-11-2011

@sriramv90

 

Hi please check below AR for details on periodic read, 

http://www.xilinx.com/support/answers/43344.html

 

It is necesary to issue periodic read for phy only design as well. You can refer below AR for more deatils 

http://www.xilinx.com/Attachment/Xilinx_Answer_51204.pdf

 

Hope this helps

 

-Vanitha 

---------------------------------------------------------------------------------------------
Please do google search before posting, you may find relavant information.
Mark the post - "Accept as solution" and give kudos if information provided is helpful and reply oriented
sriramv90
Visitor
Visitor
12,330 Views
Registered: ‎07-30-2015

Hi,

 

Thank you for your response. I have gone through the AR on periodic read. Periodic read is to send read commands if there are no read requests till 1us. Is it enough to implement a simple logic such as this:

if(read_req_received){
reset clock_count;
}
else if(clock_count == PERIODIC_READ_COUNT) {
send_read;
reset clock_cnt;
block any request till read_ack;
}
else if(clock_count < PERIODIC_READ_COUNT) {
increment clock_count;
}

 

Please advise. Thanks in advance.

 

-Sriram.

0 Kudos