EMAC Port Registers

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5.28 Receive Channel 0-7 Free Buffer Count Register (RXnFREEBUFFER)

The receive channel 0-7 free buffer count register (RXnFREEBUFFER) is shown in Figure 70 and described in Table 64.

 

Figure 70. Receive Channel n Free Buffer Count Register (RXnFREEBUFFER)

31

 

 

16

 

 

 

 

 

 

 

Reserved

 

 

 

 

 

 

 

R-0

15

 

 

0

 

 

 

 

 

 

 

RXnFREEBUF

 

 

 

 

 

 

 

WI-0

tLEGEND: R = Read only; R/W = Read/Write; WI = Write to increment; -n= value after reset

 

Table 64. Receive Channel n Free Buffer Count Register (RXnFREEBUFFER) Field Descriptions

 

 

 

 

Bit

Field

Value

Description

 

 

 

 

31-16

Reserved

0

Reserved

 

 

 

 

15-0

RXnFREEBUF

 

Receive free buffer count. These bits contain the count of free buffers available. The

 

 

 

RXFILTERTHRESH value is compared with this field to determine if low priority frames should be

 

 

 

filtered. The RXnFLOWTHRESH value is compared with this field to determine if receive flow

 

 

 

control should be issued against incoming packets (if enabled). This is a write-to-increment field.

 

 

 

This field rolls over to zero on overflow. If hardware flow control or QOS is used, the host must

 

 

 

initialize this field to the number of available buffers (one register per channel). The EMAC

 

 

 

decrements (by the number of buffers in the received frame) the associated channel register for

 

 

 

each received frame. The host must write this field with the number of buffers that have been freed

 

 

 

due to host processing.

 

 

 

 

124

C6472/TCI6486 EMAC/MDIO

SPRUEF8F –March 2006 –Revised November 2010

 

 

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Texas Instruments TMS320TCI6486 manual Receive Channel 0-7 Free Buffer Count Register RXnFREEBUFFER