Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Doubt about AHB and split transfers

Status
Not open for further replies.

hurricanebomb

Newbie level 5
Joined
Feb 21, 2007
Messages
9
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,344
hi ,all
when i design a apb_bridge ,there is a problem confused me,and i can not find any
clear expression about it in amba 2.0 specification . The problem is

Can the ahb-slave respond a split signal when the ahb-master sent
a locked transfer (hlock is active) to the slave?

Thanks all
 

Re: ahb,split transfers

No. it can't since the transfer is locked the slave should not give the split response until the transfer is finished.
 

Re: ahb,split transfers

But what if the slave is not ready to transfer data for the transaction which has been locked. A locked transfer for which data could not be transferred by the slave may cause starvation for other masters
 

ahb,split transfers

Yes then also it will keep holding the bus.. it is user/master problems , so before starting locked transfer master should know how my slave is going to respond(or what are the condition which might occur)
 

Re: ahb,split transfers

Hi

The ahb slave can definitely respond with a split to a locked transfer. The protocol allows for it. you can see AMBA FAQ which clearly states the following:

7. When will the arbiter grant another master after a locked transfer?

The arbiter will always grant the master an extra transfer at the end of a
locked sequence, so the master is guaranteed to perform one transfer with
the HMASTLOCK signal low at the end of the locked sequence. This coincides
with the data phase of the last transfer in the locked sequence.

During this time the arbiter can change the HGRANT signals to a new bus
master, but if the data phase of the last locked transfer receives either a
SPLIT or RETRY response then the arbiter will drive the HGRANT signals to
ensure that either the master performing the locked sequence remains
granted on the bus for a RETRY response, or the Dummy master is granted the
bus for the SPLIT response.


However giving a split or retry for a locked transfer is not recommended and will not serve the purpose for which split and retry were incorporated into the AHB Protocol.

Thanks
Prasad.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top