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small break time between DMA buffer switching of a certain thread
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small break time between DMA buffer switching of a certain thread

jtzheng posted on 23 Mar 2012 1:08 AM PST
Member
5 Forum Posts

Cypress doc says that there's a small break time when a certain thread switches its DMA buffer (not switching socket of the thread, but switching to next DMA buffer of the socket), how long is that time roughly? less than 1us or several micro-seconds or more?

Seems this is a difference from the FX2 chip, for FX2, there's no break time when crossing the USB FIFO buffer (e.g. for 4x 512bytes FIFO)...understood that FX3 needs more complicated design (DMA involved), but is there any idea about this breaking time?

Thanks!

 

 

Re: small break time between DMA buffer switching of a certain thread

aasi posted on 26 Mar 2012 01:37 PM PST
Cypress Employee
1073 Forum Posts

It is around 550 - 900ns. Considering auto mode. In manual mode it would have dependency based on what the application firmware is doing.

You can use the many to one configuration is one way of working around the buffer switching issue.

Regards,

Anand

Re: small break time between DMA buffer switching of a certain thread

jtzheng posted on 28 Mar 2012 11:53 PM PST
Member
5 Forum Posts

Anand,

  Thanks...

   The programming manual said 550 - 900 ns (in chapter about PPort)..,,there's another application notes about UVC said the break time is in "micro-seconds".

    550-900ns is good enough for my application.. Thanks again.

 

 



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