2.1 About the LPD-Q Q-Channel Distributor

The Low Power Distributor Q-Channel (LPD-Q) component enables a Q-Channel controller to control, and potentially sequence, multiple Q-Channel devices.

The LPD-Q supports from 1-8 device Q-Channel interfaces and can be configured to operate in the following modes:

Q-Channel expander
The controller Q-Channel transition request is broadcast to all device Q-Channels, in parallel. The transition requests that are sent to the devices can complete in any order.
Q-Channel sequencer
A controller Q-Channel transition request is passed sequentially to each device Q-Channel. Each transition request must complete before the LPD-Q can send a transition request to the next device.

The control Q-Channel (ctrl_* signals) receives power mode requests from the Q-Channel controller. The LPD-Q uses the device Q-Channels (dev_* signals) to send the requests to the devices. The LPD-Q uses clk_qactive_o to indicate when it requires a clock signal, clk.

The ctrl_qactive_o output is the logical OR of the multiple device inputs, dev_qactive_i<X>. The path from the dev_qactive_i<X> signals to the ctrl_qactive_o output is a combinatorial path.

The clk_qactive_o is a Q-Channel signal that is HIGH:

The type of response that the LPD-Q generates to the controller, in response to a quiescence request, depends on the responses that the LPD-Q receives from the devices:

Input resynchronization

The LPD-Q supports optional resynchronization on either or both the controller and device interfaces.

This section contains the following subsections:
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