AM79C978A AMD [Advanced Micro Devices], AM79C978A Datasheet - Page 199

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

23
22
21
BPE
PAM
LAFM
Bus Parity Error is set by the
Am79C978A controller when a
parity error occurred on the bus
interface during data transfers to
a receive buffer. BPE is valid only
when ENP, OFLO, or BUFF are
set. The Am79C978A controller
will only set BPE when the ad-
vanced parity error handling is
enabled by setting APERREN
(BCR20, bit 10) to 1. BPE is set
by the Am79C978A controller
and cleared by the host.
This bit does not exist when the
Am79C978A controller is pro-
grammed to use 16-bit software
structures for the descriptor ring en-
tries (BCR20, bits 7-0, SWSTYLE is
cleared to 0).
Physical Address Match is set by
the Am79C978A controller when
it accepts the received frame due
to a match of the frame’s destina-
tion address with the content of
the physical address register.
PAM is valid only when ENP is
set.
Am79C978A
cleared by the host.
This bit does not exist when the
Am79C978A controller is pro-
grammed to use 16-bit software
structures for the descriptor ring en-
tries (BCR20, bits 7-0, SWSTYLE is
cleared to 0).
Logical Address Filter Match is
set by the Am79C978A controller
when it accepts the received
frame based on the value in the
logical address filter register.
LAFM is valid only when ENP is
set.
Am79C978A
cleared by the host.
Note that if DRCVBC (CSR15, bit
14) is cleared to 0, only BAM, but
not LAFM will be set when a
Broadcast frame is received,
even if the Logical Address Filter
is programmed in such a way that
a Broadcast frame would pass
the hash filter. If DRCVBC is set
to 1 and the Logical Address Fil-
ter is programmed in such a way
LAFM
PAM
is
is
controller
controller
set
set
by
by
Am79C978A
and
and
the
the
20
19-16 RES
15-12 ONES
11-0
RMD2
Bit
31
30-16 RFRTAG
BAM
BCNT
ZERO
Name
Buffer Byte Count is the length of
Receive Frame Tag. Indicates
that a Broadcast frame would
pass the hash filter, LAFM will be
set on the reception of a Broad-
cast frame.
This bit does not exist when the
Am79C978A controller is pro-
grammed to use 16-bit software
structures for the descriptor ring en-
tries (BCR20, bits 7-0, SWSTYLE is
cleared to 0).
Broadcast Address Match is set
by the Am79C978A controller
when it accepts the received
frame, because the frame’s desti-
nation address is of the type
“Broadcast.” BAM is valid only
when ENP is set. BAM is set by
the Am79C978A controller and
cleared by the host.
This bit does not exist when the
Am79C978A controller is pro-
grammed to use 16-bit software
structures for the descriptor ring en-
tries (BCR20, bits 7-0, SWSTYLE is
cleared to 0).
Reserved locations. These loca-
tions should be read and written
as zeros.
These four bits must be written as
ones. They are written by the host
and
Am79C978A controller.
the buffer pointed to by this de-
scriptor, expressed as the two's
complement of the length of the
buffer. This field is written by the
host and unchanged by the
Am79C978A controller.
This
Am79C978A controller will write a
zero to this location.
the Receive Frame Tag applied
from the EADI interface. This
field is user defined and has a
default value of all zeros. When
Description
field
unchanged
is
reserved.
by
199
The
the