AM79C976 Datasheet, PDF (55/309 Pages) Advanced Micro Devices – PCnet-PRO™ 10/100 Mbps PCI Ethernet Controller

PRELIMINARY
Table 5. Descriptor Write Sequence
SWSTYLE
BCR20[7: AD Bus Sequence
0]
for Rx Descriptor
AD Bus Sequence
for Tx Descriptor
Address = XXXX
XX04h
Address = XXXX
XX04h
Data
Data
0
Idle
Idle
Address = XXXX
XX00h
Address = XXXX
XX00h
Data
Data
Address = XXXX
XX08h
Address = XXXX
XX08h
Data
Data
2
Idle
Idle
Address = XXXX
XX04h
Address = XXXX
XX04h
Data
Data
Address = XXXX
Address = XXXX
XX00h
3
Data
XX00h
Data
Data
Data
Address = XXXX
Address = XXXX
4
XX00h
XX00h
Data
Data
Address = XXXX
Address = XXXX
5
XX00h
XX00h
Data
Data
Note: Figure 24 assumes that the Am79C976 control-
ler is programmed to use 32-bit software structures
(SWSTYLE = 2, 3, 4, or 5). The byte enable signals for
the second data transfer would be 0111b, if the device
was programmed to use 16-bit software structures
(SWSTYLE = 0).
8/01/00
Am79C976
55