APB协议总结
概述
APB is designed for accessing the programmable control registers of peripheral devices.
信号
时序
PWAKEUP signaling （only APB5）
The wake-up signal, PWAKEUP, is used to indicate any activity associated with any APB interface. PWAKEUP provides a glitch-free signal that can be routed to a clock controller, or similar component, to enable power and clocks to connected components. The Wakeup_Signal property is used to indicate whether a component supports wake-up signaling: True Wake-up signal is present. False Wake-up signal is not present. If the Wakeup_Signal property is not declared, it is considered False.
PAUSER, PWUSER, PRUSER, PBUSER
The users of APB protocols can encounter an application that requires the addition of signaling that is not specified in the APB protocol. User signaling defines a standard method of adding this signaling to a transaction, without defining the signal usage. (可以扩展自定义信号)
