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...
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.