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some questions about flag | Cypress Semiconductor

some questions about flag

Summary: 1 Reply, Latest post by RSKV on 31 Jan 2014 10:48 PM PST
Verified Answers: 0
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user_253581985's picture
14 posts

There is  2 flag: Dedicated flag and Current flag .

1.what is the difference in them?

2. in the table 4  : there is address to Flag latency at start of transfer    for Dedicated flag is 0 cycles ;for Current flag is 2cycles +tCFLG ;But int  the Synchronous slave fifo read sequence and  the Synchronous slave fifo write sequence ,I can not find the difference about Dedicated flag and Current flag ? Can you draw it  in the picture about Dedicated flag and Current flag ?   Thank you !!!

rskv's picture
Cypress Employee
1134 posts

 Hi Chujun,

If you don't have any limitation on the GPIOs then it is better to use the dedicated flag. Dedicated flags always reflect the status of that perticular thread.

But If you use a current flag then it takes 2 clock cycles to reflect the status of  the current addressed thread. So FPGA master has to wait for 2 clock cycles before actually monitoring the status of it.


Sai Krishna. 

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