Texas Instruments TMS320DM36X manual TXnHDP

Models: TMS320DM36X

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Ethernet Media Access Controller (EMAC) Registers

5.46 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 85 and described in Table 83.

 

Figure 85. 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 83. 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.

 

 

 

 

5.47 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 86 and described in Table 84.

 

 

Figure 86. 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 84. 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.

 

 

 

 

 

SPRUFI5B –March 2009 –Revised December 2010 Ethernet Media Access Controller (EMAC)/Management Data Input/Output 121

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Texas Instruments TMS320DM36X manual TXnHDP