18.104.22.168. RX Flow Control
The RX flow control interface provides information on the application's available RX buffer space to the PCIe Hard IP in a time-division multiplexing (TDM) manner. It reports the space available in number of TLPs. Whenever TLP is read or extracted from the application RX buffer, rx_buffer_limit_i signal should increase accordingly. This information is consumed by the PCIe Hard IP to determine if application RX buffer is full and stop the received TLP to the application RX buffer.
The RX flow control interface is optional and disabled by default in the IP GUI. If disabled, it indicates that there is no limit in the application RX buffer space.
- Posted (P) transactions: TLPs that do not require a response.
- Non-posted (NP) transactions: TLPs that require a completion.
- Completions (CPL): TLPs that respond to non-posted transactions.
|Memory Read Lock||Non-posted|
|Completion with Data||Completion|
|Completion Lock with Data||Completion|
|Fetch and Add AtomicOp||Non-posted|
|RX Buffer Segment||x16 Core (Port0)||x8 Core (Port1)||x4 Core (Port2/3)|
|Scaled Flow Control disabled (Credit)||Scaled Flow Control enabled (Scale Factor , Credit)||Scaled Flow Control disabled (Credit)||Scaled Flow Control enabled (Scale Factor , Credit)||Scaled Flow Control disabled (Credit)||Scaled Flow Control enabled (Scale Factor , Credit)|
|Posted Headers||127||3 , 49||127||2 , 98||127||2 , 56|
|Posted Data||1456||1 , 1456||760||1 , 760||444||1 , 444|
|Non-posted Headers||127||3 , 49||127||2 , 98||127||2 , 56|
|Non-posted Data||392||1 , 392||196||1 , 196||112||1, 112|
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