AHB Lite Multiple burst without idle transfer

Hi All,

               Consider the following burst transfers.

1. INCR4 (WR) IDLE INCR4(RD)

2. INCR4 (WR) INCR4(RD)

3. INCR4 (WR - WR1 ,WR2, IDLE, WR3 ,WR4 )   INCR4(RD)

             All the above transactions are valid transfer or not .

Can we trigger multiple burst without giving idle transfer ?

Can we trigger IDLE transfer within the burst .

Thanks & Regards

Muthuvenkatesh

 

               

 

  • Hi Muthuvenkatesh

    I'm not too sure what your sequences are showing, so I'll explain what I think the sequences are, and then if they would be legal.

    1 - INCR4 (WR) IDLE INCR4(RD)

    This is HTRANS signalling NONSEQ-SEQ-SEQ-SEQ-IDLE-NONSEQ-SEQ-SEQ-SEQ, so 2 complete 4-beat bursts, with an IDLE in between.

    This would be legal (assuming HREADY is high for each transfer to keep things simple).

    2 - INCR4 (WR) INCR4(RD)

    The same sequence as above, but without the IDLE in between the 2 4-beat bursts.

    Again perfectly legal, there is no requirement to have an IDLE in between bursts.

    3 - INCR4 (WR - WR1 ,WR2, IDLE, WR3 ,WR4 )  INCR4(RD)

    This time HTRANS would be NONSEQ-SEQ-IDLE-SEQ-SEQ-NONSEQ-SEQ-SEQ-SEQ.

    This one is definitely illegal. An IDLE transfer can only happen outside of any burst, so it could not happen after the 2nd transfer of a 4-beat burst.

    If you need to stall a defined length burst you would instead use a BUSY transfer in place of the IDLE.

    I hope that was what you were describing.