MPC8280 datasheet(804/1386 Pages) FREESCALE

804 / 1386 page

SCC Ethernet Mode

MPC8280 PowerQUICC II Family Reference Manual, Rev. 1

25-16

Freescale Semiconductor

25.18 SCC Ethernet Receive BD

The Ethernet controller uses the RxBD to report on the received data for each buffer.

Table 25-7 describes RxBD status and control fields.

12–14

NIB

Number of ignored bits. Determines how soon after RENA assertion the Ethernet controller should

begin looking for the start frame delimiter. Typically NIB = 101 (22 bits).

000 Begin searching 13 bits after the assertion of RENA.

001 Begin searching 14 bits after the assertion of RENA.

...

111 Begin searching 24 bits after the assertion of RENA.

FDE

Full duplex Ethernet.

0 Disable full-duplex Ethernet mode.

1 Enable full-duplex Ethernet mode.

Note: When FDE = 1, PSMR[LPB] must be set also.

0123

456

789

Offset + 0

—

Offset + 2

Data Length

Offset + 4

Rx Data Buffer Pointer

Offset + 6

Figure 25-6. SCC Ethernet RxBD

Table 25-7. SCC Ethernet RxBD Status and Control Field Descriptions

Bits

Name

Description

Empty.

0 The buffer is full or stopped receiving data because an error occurred. The core can read or write

any fields of this RxBD. The CPM does not use this BD as long as the E bit is zero.

1 The buffer is not full. The CPM controls this BD and its buffer; do not modify this BD.

—

Reserved, should be cleared.

Wrap (final BD in table).

0 Not the last BD in the table.

1 Last BD in the table. After this buffer is used, the CPM receives incoming data into the first BD

that RBASE points to. The number of BDs is determined only by the W bit and overall space

constraints of the dual-port RAM.

Interrupt. Note that this bit does not mask SCCE[RXF] interrupts.

0 No SCCE[RXB] interrupt is generated after this buffer is used.

1 SCCE[RXB] or SCCE[RXF] is set when this buffer is used by the Ethernet controller. These two

bits can cause interrupts if they are enabled.

Table 25-6. PSMR Field Descriptions (continued)

Bits

Name

Description

MPC8280 Datasheet(PDF) 804 Page - Freescale Semiconductor, Inc

MPC8280 Datasheet(HTML) 804 Page - Freescale Semiconductor, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL