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142
Am79C973/Am79C975
P R E L I M I N A R Y
by H_RESET, S_RESET, or
STOP.
CSR31: Base Address of Transmit Ring Upper
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-0
BADXU
Contains the upper 16 bits of the
base address of the Transmit
Ring.
Read/Write accessible only when
either the STOP or the SPND bit
is set. These bits are unaffected
by H_RESET, S_RESET, or
STOP.
CSR32: Next Transmit Descriptor Address Lower
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-0
NXDAL
Contains the lower 16 bits of the
next transmit descriptor address
pointer.
Read/Write accessible only when
either the STOP or the SPND bit
is set. These bits are unaffected
by H_RESET, S_RESET, or
STOP.
CSR33: Next Transmit Descriptor Address Upper
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-0
NXDAU
Contains the upper 16 bits of the
next transmit descriptor address
pointer.
Read/Write accessible only when
either the STOP or the SPND bit
is set. These bits are unaffected
by H_RESET, S_RESET, or
STOP.
CSR34: Current Transmit Descriptor Address
Lower
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-0
CXDAL
Contains the lower 16 bits of the
current transmit descriptor ad-
dress pointer.
Read/Write accessible only when
either the STOP or the SPND bit
is set. These bits are unaffected
by H_RESET, S_RESET, or
STOP.
CSR35: Current Transmit Descriptor Address
Upper
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-0
CXDAU
Contains the upper 16 bits of the
current transmit descriptor ad-
dress pointer.
Read/Write accessible only when
either the STOP or the SPND bit
is set. These bits are unaffected
by H_RESET, S_RESET, or
STOP.
CSR36: Next Next Receive Descriptor Address
Lower
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-0
NNRDAL
Contains the lower 16 bits of the
next next receive descriptor ad-
dress pointer.
Read/Write accessible only when
either the STOP or the SPND bit
is set. These bits are unaffected
by H_RESET, S_RESET, or
STOP.
CSR37: Next Next Receive Descriptor Address
Upper
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-0
NNRDAU
Contains the upper 16 bits of the
next next receive descriptor ad-
dress pointer.
Read/Write accessible only when
either the STOP or the SPND bit
is set. These bits are unaffected