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Ethernet Media Access Controller (EMAC) Registers

5.45 Transmit Channel 0-7 DMA Head Descriptor Pointer Register (TXnHDP)

The transmit channel 0-7 DMA head descriptor pointer register (TXnHDP) is shown in Figure 71 and described in Table 70.

 

Figure 71. Transmit Channel n DMA Head Descriptor Pointer Register (TXnHDP)

31

16

 

TXnHDP

 

R/W-x

15

0

 

TXnHDP

R/W-x

LEGEND: R/W = Read/Write; -n= value after reset; -x = value is indeterminate after reset

Table 70. Transmit Channel n DMA Head Descriptor Pointer Register (TXnHDP)

Field Descriptions

Bit

Field

Value

Description

31-0

TXnHDP

0-FFFF FFFFh

Transmit channel n DMA Head Descriptor pointer. Writing a transmit DMA buffer descriptor

 

 

 

address to a head pointer location initiates transmit DMA operations in the queue for the

 

 

 

selected channel. Writing to these locations when they are nonzero is an error (except at reset).

 

 

 

Host software must initialize these locations to 0 on reset.

5.46 Receive Channel 0-7 DMA Head Descriptor Pointer Register (RXnHDP)

The receive channel 0-7 DMA head descriptor pointer register (RXnHDP) is shown in Figure 72 and described in Table 71.

 

Figure 72. Receive Channel n DMA Head Descriptor Pointer Register (RXnHDP)

31

16

 

RXnHDP

 

R/W-x

15

0

 

RXnHDP

R/W-x

LEGEND: R/W = Read/Write; -n= value after reset; -x = value is indeterminate after reset

Table 71. Receive Channel n DMA Head Descriptor Pointer Register (RXnHDP)

Field Descriptions

Bit

Field

Value

Description

31-0

RXnHDP

0-FFFF FFFFh

Receive channel n DMA Head Descriptor pointer. Writing a receive DMA buffer descriptor

 

 

 

address to this location allows receive DMA operations in the selected channel when a channel

 

 

 

frame is received. Writing to these locations when they are nonzero is an error (except at reset).

 

 

 

Host software must initialize these locations to 0 on reset.

106 Ethernet Media Access Controller (EMAC)/SPRU941A –April 2007

Management Data Input/Output (MDIO)

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Texas Instruments TMS320DM643X DMP manual TX nHDP