
106
Am79C961A
CSR22-23: Next Receive Buffer Address
Bit
Name
Description
31-24
RES
Reserved locations. Written as
zero and read as undefined.
Contains the next receive buffer
address to which the PCnet-ISA
II controller will store incoming
frame data.
Read/write
accessible
when STOP or SPND bits are
set.
23-0
NRBA
only
CSR24-25: Base Address of Receive Ring
Bit
Name
Description
31-24
RES
Reserved locations. Written as
zero and read as undefined.
Contains the base address of
the Receive Ring.
Read/write
accessible
when STOP or SPND bits are
set.
23-0
BADR
only
CSR26-27: Next Receive Descriptor Address
Bit
Name
Description
31-24
RES
Reserved locations. Written as
zero and read as undefined.
Contains
the
address pointer.
Read/write
accessible
when STOP or SPND bits are
set.
23-0
NRDA
next
RDRE
only
CSR28-29: Current Receive Descriptor Address
Bit
Name
Description
31-24
RES
Reserved locations. Written as
zero and read as undefined.
Contains the current RDRE
address pointer.
Read/write
accessible
when STOP or SPND bits are
set.
23-0
CRDA
only
CSR30-31: Base Address of Transmit Ring
Bit
Name
Description
31-24
RES
Reserved locations. Written as
zero and read as undefined.
Contains the base address of
the Transmit Ring.
23-0
BADX
Read/write
when STOP or SPND bits are
set.
accessible
only
CSR32-33: Next Transmit Descriptor Address
Bit
Name
Description
31-24
RES
Reserved locations. Written as
zero and read as undefined.
Contains the next TDRE address
pointer.
Read/write
accessible
when STOP or SPND bits are
set.
23-0
NXDA
only
CSR34-35: Current Transmit Descriptor Address
Bit
Name
Description
31-24
RES
Reserved locations. Written as
zero and read as undefined.
Contains the current TDRE
address pointer.
Read/write
accessible
when STOP or SPND bits are
set.
23-0
CXDA
only
CSR36-37: Next Next Receive Descriptor Address
Bit
Name
Description
31-0
NNRDA
Contains the next next RDRE
address pointer.
Read/write
accessible
when STOP or SPND bits are
set.
only
CSR38-39: Next
Next
Transmit
Descriptor Address
Bit
Name
Description
31-0
NNXDA
Contains the next next TDRE
address pointer.
Read/write
accessible
when STOP or SPND bits are
set.
only
CSR40-41: Current Receive Status and Byte Count
Bit
Name
Description
31-24
CRST
Current Receive Status. This
field is a copy of bits 15:8 of
RMD1 of the current receive
descriptor.
Read/write
accessible
when STOP or SPND bits are
set.
Reserved locations. Written as
zero and read as undefined.
only
23-12
RES