Interview Questions Related to CDC

[spartanthewarrior]

Can any body tell me

Questions related to Clock Domain Crossing and It's good if some one is having some docs related to it.

 

[owen_li]

wish below will be some helpful.

 

[owen_li]

this material is from the cadence website:

 

[Digital-L0gik]

Here are some fundamental questions?

1) What is the danger in crossing clock domains?

2) Describe some of the techniques used to do cdc safely.

 

[hellokid]

The danger of CDC is metastable.
In most of cases, an asyn FIFO or a daul port RAM will be used at boundary.

 

[Digital-L0gik]

There are many techniques around for crossing domains safely. In a very simple case where you transmit 1 bit of data to another domain double registers at the destination domain will suffice. However, for more complicated bus type transfers, 2-phase or 4-phase handshaking schemes can be implemented. When transmitting chunks of data fifos are good options.

Visit this site for some good information on the subject:

https://www.fpga4fun.com/CrossClockDomain.html

Be sure to read through the links provided!