I want to know what is peripheral at low-power in AXI.
please explain with example.
and why use low-power in AXI
I just read "The low-power interface is an optional extension to the data transfer protocol that targets two different classes of peripherals" in spec
As the peripheral with the low power interface still needs to be able to signal when it does, and does not, need a clock, this isn't an interface to support complete removal of power from the peripheral, it is instead indicating when it needs ACLK to be actively driven, and that way saving power if dormant registers are not being actively clocked.
So if you have a periperal in your system that you know won't be needed for a long time, it makes sense to remove the active clock from that peripheral, and this interface then supports a method of signaling when the clock is needed from the clock controller
There are then two classes of peripheral described, the simplest being when the peripheral can just have its clock stopped with no preparation required, and the more complex where the peripheral needs to go through some "power-down" or "power-up" sequence before or after the clock is stopped or restarted.
The interface is optional, so if you don't see a need for stopping clocks to some peripherals, you don't need to implement it, and the ACLK inpiut will just be permanently on.