
138
Am79C965A
15-0
NXDA
Contains the lower 16 bits of the
next TDRE address pointer.
Read/write accessible only when
STOP bit is set.
CSR33: Next Transmit Descriptor Address Upper
Bit
Name
Description
31-16 RES
Reserved locations. Written as
zeros and read as undefined.
15-0
NXDA
Contains the upper 16 bits of the
next TDRE address pointer.
Read/write accessible only when
STOP bit is set.
CSR34: Current Transmit Descriptor Address
Lower
Bit
Name
Description
31-16 RES
Reserved locations. Read and
written as zero.
15-0
CXDA
Contains the lower 16 bits of the
current TDRE address pointer.
Read/write accessible only when
STOP bit is set.
CSR35: Current Transmit Descriptor Address
Upper
Bit
Name
Description
31-16 RES
Reserved locations. Written as
zeros and read as undefined.
15-0
CXDA
Contains the upper 16 bits of the
current TDRE address pointer.
Read/write accessible only when
STOP bit is set.
CSR36: Next Next Receive Descriptor Address
Lower
Bit
Name
Description
31-16 RES
Reserved locations. Written as
zeros and read as undefined.
15-0
NNRDA
Contains the lower 16 bits of the
next next receive descriptor ad-
dress pointer.
Read/write accessible only when
STOP bit is set.
CSR37: Next Next Receive Descriptor Address
Upper
Bit
Name
Description
31-16 RES
Reserved locations. Written as
zeros and read as undefined.
15-0
NNRDA
Contains the upper 16 bits of the
next next receive descriptor ad-
dress pointer.
Read/write accessible only when
STOP bit is set.
CSR38: Next Next Transmit Descriptor Address
Lower
Bit
Name
Description
31-16 RES
Reserved locations. Written as
zeros and read as undefined.
15-0
NNXDA
Contains the lower 16 bits of the
next next transmit descriptor ad-
dress pointer.
Read/write accessible only when
STOP bit is set.
CSR39: Next Next Transmit Descriptor Address
Upper
Bit
Name
Description
31-16 RES
Reserved locations. Written as
zeros and read as undefined.
15-0
NNXDA
Contains the upper 16 bits of the
next next transmit descriptor ad-
dress pointer.
Read/write accessible only when
STOP bit is set.
CSR40: Current Receive Status and Byte Count
Lower
Bit
Name
Description
31-16 RES
Reserved locations. Written as
zeros and read as undefined.
15-12 RES
Reserved locations. Read and
written as zero.
11-0
CRBC
Current Receive Byte Count. This
field is a copy of the BCNT field of
RMD2 of the current receive
descriptor.
Read/write accessible only when
STOP bit is set.
CSR41: Current Receive Status and Byte Count
Upper
Bit
Name
Description
31-16 RES
Reserved locations. Written as
zeros and read as undefined.
15-8
CRST
Current Receive Status. This field is
a copy of bits 15:8 of RMD1 of the
current receive descriptor.