AM79C978 Advanced Micro Devices, AM79C978 Datasheet - Page 155

• Manufacturer Part Number: AM79C978
• Description: Single-Chip 1/10 Mbps PCI Home Networking Controller
• Manufacturer: Advanced Micro Devices

1
0
BCR9: Full-Duplex Control
Note: Bits 15-0 in this register are programmable
through the EEPROM.
Bit
31-3
2
SPEED
COLE
RES
FDRPAD
Name
register when there is receive ac-
tivity on the network.
Speed. When this bit is set to 1,
the device is operating in HIGH
speed mode.
Collision Status Enable. When
this bit is set, a value of 1 is
passed to the LEDOUT bit in this
register when there is collision
activity on the network.
Reserved locations. Written as
zeros and read as undefined.
Full-Duplex Runt Packet Accept
Disable. When FDRPAD is set to
1 and full-duplex mode is en-
abled, the Am79C978 controller
will only receive frames that meet
the minimum Ethernet frame
length of 64 bytes. Receive DMA
will not start until at least 64 bytes
or a complete frame have been
received. By default, FDRPAD is
cleared to 0. The Am79C978 con-
troller will accept any length
frame and receive DMA will start
according to the programming of
the receive FIFO watermark.
Note that there should not be any
runt packets in a full-duplex net-
work, since the main cause for
runt packets is a network collision
and there are no collisions in a
full-duplex network.
This bit is always read/write ac-
cessible. RCVE is cleared by
H_RESET and is not affected by
S_RESET or setting the STOP
bit.
This bit is always read/write ac-
cessible. COLE is cleared by
H_RESET and is not affected by
S_RESET or setting the STOP
bit.
This bit is always read/write ac-
cessible. FDRPAD is cleared by
H_RESET and is not affected by
Description
Am79C978
1
0
BCR16: I/O Base Address Lower
Bit
31-16 RES
15-5
4-0
BCR17: I/O Base Address Upper
Bit
31-16 RES
15-0
RES
FDEN
IOBASEL
RES
IOBASEU
Name
Name
S_RESET or by setting the STOP
bit.
Reserved locations. Written as
zeros and read as undefined.
Full-Duplex Enable. FDEN con-
trols whether full-duplex opera-
tion is enabled. When FDEN is
cleared and the Auto-Negotiation
is disabled, full-duplex operation
is
Am79C978 controller will always
operate in half-duplex mode.
When
Am79C978 controller will operate
in full-duplex mode. Do not set
this bit when Auto-Negotiation
is enabled.
This bit is always read/write ac-
cessible. FDEN is reset to 0 by
H_RESET, and is unaffected by
S_RESET and the STOP bit.
Reserved locations. Written as
zeros and read as undefined.
Reserved
H_RESET, the value of these bits
will be undefined. The settings of
these bits will have no effect on
any Am79C978 controller func-
tion.
These bits are always read/write
accessible. IOBASEL is not af-
fected by S_RESET or STOP.
Reserved locations. Written as
zeros, read as undefined.
Reserved locations. Written as
zeros and read as undefined.
Reserved
H_RESET, the value in this regis-
ter will be undefined. The settings
of this register will have no effect
on any Am79C978 controller
function.
Description
Description
not
FDEN
enabled
locations.
locations.
is
and
set,
After
After
155
the
the