1)what are the different generations in AMBA AHB?
There have been 3 releases of the AHB protocol.
The original AHB released in 1999, officially "AMBA 2 AHB", supported multiple masters on a single bus, so had HBUSREQ and HGRANT arbitration controls for masters, and SPLIT and RETRY responses for slaves to try to avoid a stalled transfer from one master blocking all other masters from using the bus.
Then there was a simplified version of the original AHB, documented in 2006, called AHB-lite or "AMBA 3 AHB-lite" for the official name. AHB-lite removed the multi-master support, so none of the arbitration signals and no SPLIT or RETRY responses. AHB-lite was aimed at use in a multi-layer BusMatrix type system where each master sat on its own "layer" and a BusMatrix would support access to shared slaves, so adding parallel processing support to improve system performance compared to all masters sharing one single AHB.
The last release in 2015 was AHB5, "AMBA 5 AHB" being the full name. This added features to the AHB-lite protocol, features often seen in AXI style protocols, so support for exclusive accesses, better defined memory type signalling, support for security signalling, user signals and support for byte invariant endian transfers.
The 3 releases have the same fundamental operation, so are largely compatible with each other, with each newer release adapting the previous definition to suit the current use requirements at that time.
is AMBA 5 AHB supports the SPLIT signal?
I'm assuming you mean the HSPLIT signal.
No, this was only in the original AMBA 2 AHB protocol.
As AHB5 supports just a single master on each "layer" of an interconnect, there is no need for an HSPLIT signal which tells an arbiter when a master can be re-granted on a shared bus.
No arbiter in AMBA 5 AHB, so can I say that AMBA5 AHB does not support the multiple master architecture only support for the single master, multiple slaves?
A single AHB5 bus only supports one master, just like in AMBA 3 AHB-lite.
However most applications of AHB5 (and AHB-lite) will use a multi-layer interconnect or busmatrix, and that will then support one AHB5 master per layer.
Then inside the busmatrix you will need arbitration logic to decide which master layer gets access to a shared slave when 2 or more master layers request access at the same time.
So I would say that it would NOT be correct to simply state "AMBA 5 AHB does not support multiple master architecture" as multiple masters can be supported if the system uses a multi-layer busmatrix strructure.
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