The following table defines the ports in the Configuration Flow Control interface of the core.
| Port | Direction | Width | Description |
|---|---|---|---|
| cfg_fc_ph | Output | 8 |
Posted Header Flow Control Credits. This output provides the number of Posted Header Flow Control Credits. This multiplexed output can be used to bring out various flow control parameters and variables related to Posted Header Credit maintained by the core. The flow control information to bring out on this core is selected by the cfg_fc_sel[2:0] input. |
| cfg_fc_pd | Output | 12 |
Posted Data Flow Control Credits. This output provides the number of Posted Data Flow Control Credits. This multiplexed output can be used to bring out various flow control parameters and variables related to Posted Data Credit maintained by the core. The flow control information to bring out on this core is selected by the cfg_fc_sel[2:0] input. |
| cfg_fc_nph | Output | 8 |
Non-Posted Header Flow Control Credits. This output provides the number of Non-Posted Header Flow Control Credits. This multiplexed output can be used to bring out various flow control parameters and variables related to Non-Posted Header Credit maintained by the core. The flow control information to bring out on this core is selected by the cfg_fc_sel[2:0] input. |
| cfg_fc_npd | Output | 12 |
Non-Posted Data Flow Control Credits. This output provides the number of Non-Posted Data Flow Control Credits. This multiplexed output can be used to bring out various flow control parameters and variables related to Non-Posted Data Credit maintained by the core. The flow control information to bring out on this core is selected by the cfg_fc_sel[2:0] input. |
| cfg_fc_cplh | Output | 8 |
Completion Header Flow Control Credits. This output provides the number of Completion Header Flow Control Credits. This multiplexed output can be used to bring out various flow control parameters and variables related to Completion Header Credit maintained by the core. The flow control information to bring out on this core is selected by the cfg_fc_sel[2:0] input. |
| cfg_fc_cpld | Output | 12 |
Completion Data Flow Control Credits. This output provides the number of Completion Data Flow Control Credits. This multiplexed output can be used to bring out various flow control parameters and variables related to Completion Data Credit maintained by the core. The flow control information to bring out on this core is selected by the cfg_fc_sel[2:0]. |
| cfg_fc_sel | Input | 3 |
Flow Control Informational Select. These inputs select the type of flow control to bring out on the cfg_fc_* outputs of the core. The various flow control parameters and variables that can be accessed for the different settings of these inputs are: 000: Receive credits currently available to the link partner 001: Receive credit limit 010: Receive credits consumed 011: Available space in receive buffer 100: Transmit credits available 101: Transmit credit limit 110: Transmit credits consumed 111: Reserved This value represents the actual unused credits in the receiver FIFO, and the recommendation is to use it only as an approximate indication of receiver FIFO fullness, relative to the initial credit limit value advertized, such as, ¼ full, ½ full, ¾ full, full. Note: Infinite credit for transmit credits available
(cfg_fc_sel == 3'b100) is signaled as 8'h80, 12'h800 for header and data credits,
respectively. For all other cfg_fc_sel selections, infinite credit is signaled as
8'h00, 12'h000, respectively, for header and data categories.
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