Using AHB split transfer in FSM

[prashanthaditya]

Hi Guys,

In AHB,when slave can give spilt response to the master based on its decision.

Thats why when you implementing in a FSM (slave interface) , to give split response to master,how will you judge split transfer??

I mean to say on which condition your FSM will give split transfer to MAster???


P

 

[viju]

retry split

Hi ,
The split transfer should be given when you as a slave sure that you will take huge time (in terms of clock cycles) to give response to Master from which you got the request.

spec says..."The SPLIT and RETRY response combinations allow slaves to delay the completion of
a transfer, but free up the bus for use by other masters. These response combinations are
usually only required by slaves that have a high access latency and can make use of
these response codes to ensure that other masters are not prevented from accessing the
bus for long periods of time."
So you can design in such a way that when ever your slave have response latency of more that certain watermark level, you can issue the Split response.
This depends on the system and kind of slave you are attaching...

Hope this helps...

 

[heartfree]

ahb master bus request after split response

For example,
For AHB write transaction, if the command buffer or data buffer is full, the slave has to stop the master, so it will give split response to master. it will be good to a shared AHB bus.