CCIX Activation/Deactivation - 3.0 English

AXI Bridge for PCI Express Gen3 Subsystem Product Guide (PG194)

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3.0 English

Four states define how a CCIX link moves from deactivation to activation, and activation to deactivation.

Note: When moving activation to deactivation, it is important that the credit exchange is carefully controlled to avoid loss of data or credits in the CCIX link. The CCIX link must be in quiesce state.

The following table describes the four state transitions.

Table 1. Four State Transitions
State Name Description
Stop The CCIX link is in reset state or low power state. All the credits are with receiver and transmitter, and are not permitted to send any valid data.
Run The CCIX link is in operation state. Both components can active transfer valid data and credits.
Activate Intermediate state when moving from Stop to Run.
Deactivate Intermediate state when moving from Run to Stop.
The following figure shows the four state transitions that are based on a pair of interface signals used as a concatenation:
  • ccix_tx_active_req and ccix_tx_active_ack, or
  • ccix_rx_active_req and ccix_rx_active_ack.
Figure 1. CCIX Link State Transitions