NIC400: What is the difference between ahblitetarget and ahbliteinitiator

Looking at the bus protocols an AHB-lite Manager initiates transfer requests so is the "initiator" and can be recognised by having just one HREADY input. And an AHB-lite Subordinate receives transfer requests so is the "target" and can be recognised by having an HSEL input and 2 HREADY connections (HREADYOUT and HREADY).

When connecting AHB-lite components to a NIC-400 you have two options. The first is to directly connect to the single external component, and the second is to have the NIC-400 interface appear as a single component to connect to the rest of the system.

Looking at the NIC-400 ASIB interfaces (traditionally on the left or top of the NIC-400 block diagram where transfer requests come in), you can directly connect an upstream external AHB-lite "manager" where this NIC-400 interface is defined as an "ahbliteinitiator", or the NIC-400 can be just one of multiple AHB-lite "subordinate" components where the NIC-400 is then the "ahblitetarget".

And looking at the NIC-400 AMIB interfaces (traditionally on the right or bottom of the block diagram where transfer requests come out), you can directly connect a downstream external AHB-lite "subordinate" where this NIC-400 interface type is defined as an "ahblitetarget", or the NIC-400 can be the AHB-lite "manager" component driving the downstream system where the NIC-400 in then the "ahbliteinitiator".

So AHB-lite ASIBs and AMIBs on the NIC-400 can be either "ahbliteinitiator" or "ahblitetarget", and it is down to the pins you need to see on the interface that determines which "ahblite" type to select ("initiator" is just one HREADY, "target" is two HREADY ports and one HSEL).

The original NIC-400 documentation read in conjunction with the Socrates or AMBA Designer GUI tools all use different terms when referring to the AHB-lite ports, so hopefully the above make more sense.

Looking at the bus protocols an AHB-lite Manager initiates transfer requests so is the "initiator" and can be recognised by having just one HREADY input. And an AHB-lite Subordinate receives transfer requests so is the "target" and can be recognised by having an HSEL input and 2 HREADY connections (HREADYOUT and HREADY).

When connecting AHB-lite components to a NIC-400 you have two options. The first is to directly connect to the single external component, and the second is to have the NIC-400 interface appear as a single component to connect to the rest of the system.

Looking at the NIC-400 ASIB interfaces (traditionally on the left or top of the NIC-400 block diagram where transfer requests come in), you can directly connect an upstream external AHB-lite "manager" where this NIC-400 interface is defined as an "ahbliteinitiator", or the NIC-400 can be just one of multiple AHB-lite "subordinate" components where the NIC-400 is then the "ahblitetarget".

And looking at the NIC-400 AMIB interfaces (traditionally on the right or bottom of the block diagram where transfer requests come out), you can directly connect a downstream external AHB-lite "subordinate" where this NIC-400 interface type is defined as an "ahblitetarget", or the NIC-400 can be the AHB-lite "manager" component driving the downstream system where the NIC-400 in then the "ahbliteinitiator".

So AHB-lite ASIBs and AMIBs on the NIC-400 can be either "ahbliteinitiator" or "ahblitetarget", and it is down to the pins you need to see on the interface that determines which "ahblite" type to select ("initiator" is just one HREADY, "target" is two HREADY ports and one HSEL).

The original NIC-400 documentation read in conjunction with the Socrates or AMBA Designer GUI tools all use different terms when referring to the AHB-lite ports, so hopefully the above make more sense.