AM79C978A AMD [Advanced Micro Devices], AM79C978A Datasheet - Page 200

• Manufacturer Part Number: AM79C978A
• Description: Single-Chip 1/10 Mbps PCI Home Networking Controller
• Manufacturer: AMD [Advanced Micro Devices]

15-12 ZEROS
11-0
200
CXDA+0Ch
CXDA+0Ch
CXDA+00h
CXDA+04h
CXDA+08h BUFF UFLO EXDEF
CXDA+00h BUFF UFLO EXDEF
CXDA+04h
CXDA+08h
Address
Address
CXDA+00h
CXDA+02h
CXDA+04h
CXDA+06h
Address
MCNT
OWN
OWN
31
31
BUFF
OWN
15
1
This
Message Byte Count is the length
RXFRTG (CSR7, bit 14) is set to
0, RFRTAG will be read as all ze-
ros. See the section on Receive
Frame Tagging for details.
Am79C978A controller will write
zeros to these locations.
in bytes of the received message,
expressed as an unsigned binary
integer. MCNT is valid only when
ERR is clear and ENP is set.
MCNT
Am79C978A
cleared by the host.
ERR
ERR
30
30
field
UFLO
ADD_
ADD_
ERR
FCS
FCS
14
29
29
1
is
Table 83. Transmit Descriptor (SWSTYLE = 0)
Table 84. Transmit Descriptor (SWSTYLE = 2)
Table 85. Transmit Descriptor (SWSTYLE = 3)
is
written
MORE/
MORE/
LTINT
LCOL
LCOL
LTINT
EXDEF
controller
ADD_
28
28
reserved.
FCS
13
1
LCAR
LCAR
ONE
ONE
by
27
27
MORE/
LTINT
LCOL
12
1
Am79C978A
The
and
the
RTRY
RTRY
DEF
DEF
26
26
LCAR
USER SPACE
USER SPACE
ONE
TBADR[31:0]
TBADR[31:0]
11
TBADR[15:0]
RMD3
Bit
31-0
Transmit Descriptors
When SWSTYLE (BCR20, bits 7-0) is set to 0, the soft-
ware structures are defined to be 16 bits wide, and
transmit descriptors look like Table 83 (CXDA = Current
Transmit Descriptor Address).
When SWSTYLE (BCR 20, bits 7-0) is set to 2, the
software structures are defined to be 32 bits wide, and
transmit descriptors look like Table 84 (CXDA = Current
Transmit Descriptor Address).
When SWSTYLE (BCR 20, bits 7-0) is set to 3, then the
software structures are defined to be 32 bits wide, and
transmit descriptors look like Table 85 (CXDA = Current
Transmit Descriptor Address).
STP
RES
STP
25
25
RTRY
DEF
US
10
Name
ENP
RES
ENP
24
24
RES
BPE
BPE
RES
23
23
STP
9
User Space. Reserved for user
defined space.
Description
BCNT
22-16
22-16
RES
RES
RES
ENP
8
15-12
15-12
1111
1111
RES
TDR
TBADR[23:16]
11-4
RES
11-4
RES
7-0
BCNT
BCNT
TRC
TRC
3-0
3-0