Chapter 11. Ethernet Module
11-29
Programming Model
This register is not reset and must be initialized by the user prior to operation.
11.5.20 Pointer-to-Transmit Descriptor Ring
(X_DES_START)
This register provides a pointer to the start of the circular transmit buffer descriptor queue
in external memory. This pointer must be long-word aligned. However, it is recommended
it be aligned on a 16 byte boundary (address evenly divisible by 16) in order to improve bus
utilization. Bits 1 and 0 should be set to 0 by the user. Non-zero values in these two bit
positions are ignored by the hardware.
This register is not reset and must be initialized by the user prior to operation.
31
16
Field
R_DES_START
Reset
Undefined
R/W
Read/Write
15
2
1
0
Field
R_DES_START
0
0
Reset
Undefined
R/W
Read/Write
Addr
MBAR + 0xC10
Figure 11-23. Pointer to Receive Descriptor Ring (R_DES_START)
Table 11-27. R_DES_START Field Descriptions
Bits
Name
Description
31–2
R_DES_START
Pointer to start of receive buffer descriptor queue.
1–0
—
Reserved, should be cleared.
31
16
Field
X_DES_START
Reset
Undefined
R/W
Read/Write
15
2
1
0
Field
X_DES_START
0
0
Reset
Undefined
R/W
Read/Write
Addr
MBAR + 0xC14
Figure 11-24. Pointer to Transmit Descriptor Ring (X_DES_START)
Summary of Contents for DigitalDNA ColdFire MCF5272
Page 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
Page 38: ...xxxviii MCF5272 User s Manual TABLES Table Number Title Page Number ...
Page 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Page 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Page 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Page 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Page 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Page 338: ...13 44 MCF5272 User s Manual Application Examples ...
Page 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Page 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Page 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Page 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...