126
Am79C978A
CSR19: Current Receive Buffer Address Upper
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-0
CRBAU
Contains the upper 16 bits of the
current receive buffer address at
which the Am79C978A controller
will store incoming frame data.
These bits are read/write acces-
sible only when either the STOP
or the SPND bit is set. These bits
are unaffected by H_RESET,
S_RESET, or STOP.
CSR20: Current Transmit Buffer Address Lower
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-0
CXBAL
Contains the lower 16 bits of the
current transmit buffer address
from which the Am79C978A con-
troller is transmitting.
These bits are read/write acces-
sible only when either the STOP
or the SPND bit is set. These bits
are unaffected by H_RESET,
S_RESET, or STOP.
CSR21: Current Transmit Buffer Address Upper
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-0
CXBAU
Contains the upper 16 bits of the
current transmit buffer address
from which the Am79C978A con-
troller is transmitting.
These bits are read/write acces-
sible only when either the STOP
or the SPND bit is set. These bits
are unaffected by H_RESET,
S_RESET, or STOP.
CSR22: Next Receive Buffer Address Lower
Bit
Name
Description
31-16 RES
Reserved locations. Written as
zeros and read as undefined.
15-0 NRBAL
Contains the lower 16 bits of the
next receive buffer address to
which the Am79C978A controller
will store incoming frame data.
These bits are read/write acces-
sible only when either the STOP
or the SPND bit is set. These bits
are unaffected by H_RESET,
S_RESET, or STOP.
CSR23: Next Receive Buffer Address Upper
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-0
NRBAU
Contains the upper 16 bits of the
next receive buffer address to
which the Am79C978A controller
will store incoming frame data.
These bits are read/write acces-
sible only when either the STOP
or the SPND bit is set. These bits
are unaffected by H_RESET,
S_RESET, or STOP.
CSR24: Base Address of Receive Ring Lower
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-0
BADRL
Contains the lower 16 bits of the
base address of the Receive
Ring.
These bits are read/write acces-
sible only when either the STOP
or the SPND bit is set. These bits
are unaffected by H_RESET,
S_RESET, or STOP.
CSR25: Base Address of Receive Ring Upper
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-0
BADRU
Contains the upper 16 bits of the
base address of the Receive
Ring.
These bits are read/write acces-
sible only when either the STOP
or the SPND bit is set. These bits