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Fast Ethernet Controller (FEC)
PXN20 Microcontroller Reference Manual, Rev. 1
25-28
Freescale Semiconductor
25.3.4.23 Transmit Buffer Descriptor Ring Start Register (ETDSR)
The ETDSR is written by the user. It provides a pointer to the start of the circular transmit buffer descriptor
queue in external memory. This pointer must be 32-bit aligned; however, it is recommended it be made
128-bit aligned (evenly divisible by 16). Bits 30 and 31 should be written 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.
Offset: FE 0x0180
Access: User read/write
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
R
R_DES_START
W
Reset
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
R
R_DES_START
0
0
W
Reset
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
Figure 25-23. Receive Descriptor Ring Start Register (ERDSR)
Table 25-25. ERDSR Field Descriptions
Field
Descriptions
R_DES_START
Pointer to start of receive buffer descriptor queue.
30–31
Reserved, should be cleared.
Offset: FE 0x0184
Access: User read/write
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
R
X_DES_START
W
Reset
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
R
X_DES_START
0
0
W
Reset
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
Figure 25-24. Transmit Buffer Descriptor Ring Start Register (ETDSR)
Summary of Contents for PXN2020
Page 1: ...PXN20 Microcontroller Reference Manual Devices Supported PXN2020 PXN2120 PXN20RM Rev 1 06 2011...
Page 42: ...PXN20 Microcontroller Reference Manual Rev 1 lxiv Freescale Semiconductor...
Page 64: ...Introduction PXN20 Microcontroller Reference Manual Rev 1 1 22 Freescale Semiconductor...
Page 112: ...Signal Description PXN20 Microcontroller Reference Manual Rev 1 3 44 Freescale Semiconductor...
Page 118: ...Resets PXN20 Microcontroller Reference Manual Rev 1 4 6 Freescale Semiconductor...
Page 372: ...e200z6 Core Z6 PXN20 Microcontroller Reference Manual Rev 1 13 8 Freescale Semiconductor...
Page 412: ...e200z0 Core Z0 PXN20 Microcontroller Reference Manual Rev 1 14 14 Freescale Semiconductor...
Page 821: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 Freescale Semiconductor 27 49...
Page 822: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 27 50 Freescale Semiconductor...
Page 1376: ...Memory Map PXN20 Microcontroller Reference Manual Rev 1 A 118 Freescale Semiconductor...