Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Question about PLL frequency in at-speed test for DFT

Status
Not open for further replies.

liwei039

Newbie level 6
Newbie level 6
Joined
May 9, 2007
Messages
11
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,355
when I do at-speed DFT, I want to using the PLL output as refclk1 for launch and capture clock.
But there is a question, if the default PLL output clock frequency is not what I want. How can I make the PLL output clock turn to the right frequecy?
Use strap pin?

2. Can I config the PLL register to change the PLL frequency? I dont think so, but why?

thanks
 

maulin sheth

Advanced Member level 1
Advanced Member level 1
Joined
Oct 24, 2010
Messages
499
Helped
90
Reputation
179
Reaction score
89
Trophy points
1,318
Location
Bangalore, India
Activity points
4,140
Hello

If you need to generate required PLL frequency..thn you need to config the PLL register.Because only through PLL we can generate at speed frequency.
 

liwei039

Newbie level 6
Newbie level 6
Joined
May 9, 2007
Messages
11
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,355
So, I can config the PLL register when the chip is under the scan mode. the frequency of PLL config register ck pin is scan clock?
 

maulin sheth

Advanced Member level 1
Advanced Member level 1
Joined
Oct 24, 2010
Messages
499
Helped
90
Reputation
179
Reaction score
89
Trophy points
1,318
Location
Bangalore, India
Activity points
4,140
Yes,you can do it.
OCC is on your chip or not? Basically through OCC we generate the clock (scan,launch and capture clocks).
 

liwei039

Newbie level 6
Newbie level 6
Joined
May 9, 2007
Messages
11
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,355
Thanks, yes, there is OCC in my chip. Is there some other things to be done besides configuration PLL registers?
Due to the PLL needs some time to be stable after configuration, so what I should do in the ATPG patterns? waiting some cycle times ?
 

maulin sheth

Advanced Member level 1
Advanced Member level 1
Joined
Oct 24, 2010
Messages
499
Helped
90
Reputation
179
Reaction score
89
Trophy points
1,318
Location
Bangalore, India
Activity points
4,140
For that you need the documentation of PLL which is used in your design. yea we have to give some time to stable the required PLL output....yea..you have to wait for some cycles...
 

liwei039

Newbie level 6
Newbie level 6
Joined
May 9, 2007
Messages
11
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,355
Thanks a lot. Can I use the strap pin for configuration the PLL? Is this a little fast than RISC to config that PLL register?
 

maulin sheth

Advanced Member level 1
Advanced Member level 1
Joined
Oct 24, 2010
Messages
499
Helped
90
Reputation
179
Reaction score
89
Trophy points
1,318
Location
Bangalore, India
Activity points
4,140
I think whn you config the PLL thn the PLL ip is in functional mode, thn by using the PLL lock and power down mode, you can switch to test mode (this information you can get from the PLL documentation)...
Yea if any strap pin is available thn we can use it....

BTW you can refer the testbench of PLL for just understanding how to work with PLL for particular frequency...
 

liwei039

Newbie level 6
Newbie level 6
Joined
May 9, 2007
Messages
11
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,355
Thank you very much. Do you have a simple testbench and PLL design or PLL documentation.

- - - Updated - - -

Thank you very much. Do you have a simple testbench and PLL design or PLL documentation.
 

maulin sheth

Advanced Member level 1
Advanced Member level 1
Joined
Oct 24, 2010
Messages
499
Helped
90
Reputation
179
Reaction score
89
Trophy points
1,318
Location
Bangalore, India
Activity points
4,140
Sorry.I am DFT engineer so I don't have the simple PLL testbench.
Really sorry I can't help for document and testbench.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top