Module ip_mac_fc_gen_g
Block Diagram of ip_mac_fc_gen_g
Name |
Type |
Direction |
Description |
|---|---|---|---|
pi_reset |
wire logic |
input |
Global Hardware/Software reset (active low) |
pi_g_clock |
wire logic |
input |
Transmit GMII/MII 125/25/2.5 MHz clock (from Clock Manager, gated clock) |
pi_f_clock |
wire logic |
input |
Transmit GMII/MII 125/25/2.5 MHz clock (from Clock Manager, free clock) |
po_en_clock |
reg |
output |
Transmit GMII/MII 125/25/2.5 MHz clock gated clock enable |
pi_fc_addr |
wire logic [2 : 0] |
input |
Command interface Next FC word request (from TX state) |
pi_fc_enable |
wire logic |
input |
Enable flow control |
pi_xon_value |
wire logic [15 : 0] |
input |
from configuration XOFF flow control pause value |
pi_xoff_value |
wire logic [15 : 0] |
input |
from configuration XON flow control pause value |
pi_fc_xon_tgl |
wire logic |
input |
Request insert FC XON/XOFF (each time the following input toggle) from RX EMAC insert XOFF flow control information |
pi_fc_xoff_tgl |
wire logic |
input |
from RX EMAC insert XON flow control information |
pi_half_duplex |
wire logic |
input |
Half duplex flow control |
pi_col_limit |
wire logic [4 : 0] |
input |
Half duplex back pressure collision limit |
pi_gmii_col |
wire logic |
input |
Collision indication used to count the collisions during HD FC enable |
po_hd_fc_en |
reg |
output |
Half Duplex flow control enable |
po_fc_ready |
reg |
output |
FC frame interface Request to insert a new FC frame |
po_fc_eop |
reg |
output |
Note: When asserted has the meaning of ready and start of frame Flow control frame end of frame |
po_fc_sop |
reg |
output |
Flow control frame start of frame |
po_fc_data |
reg [31 : 0] |
output |
Flow control frame data |
Always Blocks
- always @ ( posedge pi_g_clock or negedge pi_reset )
Data Count Process
- always @ ( posedge pi_g_clock or negedge pi_reset )
FC Data Out Process
- always @ ( posedge pi_f_clock or negedge pi_reset )
Clock Gating Module
Instances
- ip_emac_top : ip_emac_top
- mac_top : ip_mac_top_g
- mac_tx_top : ip_mac_tx_top_g
tx_fc_gen : ip_mac_fc_gen_g
The flow control (PAUSE) operation is used to inhibit transmission of data frames for a specified period of time. A MAC Control client wishing to inhibit transmission of data frames from another station on the network generates a MAC CONTROL frame specifying:
The PAUSE operation cannot be used to inhibit transmission of MAC Control frames. PAUSE frames shall only be sent by MAC's configured to the full duplex mode of operation. The globally assigned 48-bit multicast address 01-80-C2-00-00-01 has been reserved for use in MAC Control PAUSE frames for inhibiting transmission of data frames from a MAC in a full duplex mode.