Protocols
Q-Channel Protocol
An ARM protocol for power state handshaking between a power controller and peripheral devices.
Detailed Explanation
Q-Channel provides a simple interface for power state management. The controller requests power state transitions (on, retention, off); the device acknowledges when ready. This coordinates power-down sequences to avoid corruption.
The protocol uses request-acknowledge handshaking: QREQn requests a state, QACCEPTn indicates device is ready to enter that state. Denial is possible—devices can refuse power-down if busy.