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Am79C973/Am79C975
143
P R E L I M I N A R Y
by H_RESET, S_RESET, or
STOP.
CSR38: Next Next Transmit Descriptor Address
Lower
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-0
NNXDAL
Contains the lower 16 bits of the
next next 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.
CSR39: Next Next Transmit Descriptor Address
Uper
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-0
NNXDAU
Contains the upper 16 bits of the
next next 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.
CSR40: Current Receive Byte Count
Bit
31-16
Name
RES
Description
Reserved locations. Written as
zeros and read as undefined.
15-12
RES
Reserved locations. Read and
written as zeros.
11-0
CRBC
Current Receive Byte Count.
This field is a copy of the BCNT
field of RMD1 of the current re-
ceive descriptor.
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.
CSR41: Current Receive Status
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-0
CRST
Current Receive Status. This
field is a copy of bits 31-16 of
RMD1 of the current receive de-
scriptor.
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.
CSR42: Current Transmit Byte Count
Bit
Name
Description
31-16
RES
Reserved locations. Written as
zeros and read as undefined.
15-12
RES
Reserved locations. Read and
written as zeros.
11-0
CXBC
Current Transmit Byte Count.
This field is a copy of the BCNT
field of TMD1 of the current trans-
mit descriptor.
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.
CSR43: Current Transmit Status
Bit
Name
Description
31-16 RES
Reserved locations. Written as
zeros and read as undefined.
15-0
CXST
Current Transmit Status. This
field is a copy of bits 31-16 of
TMD1 of the current transmit de-
scriptor.
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.
CSR44: Next Receive Byte Count
Bit
Name
Description