I came across a feature "unaligned address access" in APB4 and started implementing the same. I researched a bit but didnt exactly got what is unaligned address access. Is it same as unaligned transfers that we perform in AXI4?
The alignment of the access refers to the address being a multiple of the transfer size. For example, an aligned 32 bit access will have the bottom 4 bits of the address as 0x0, 0x4, 0x8 and 0xC assuming the memory is byte addressed.
An unaligned address is then an address that isn't a multiple of the transfer size. The meaning in AXI4 would be the same.
An an aside, I don't believe the APB4 specification discusses address alignment, and you'll find that many APB slaves only accept aligned addresses, since the APB port is normally for basic register accesses