AM79C976 Advanced Micro Devices, AM79C976 Datasheet - Page 55

• Manufacturer Part Number: AM79C976
• Description: PCnet-PRO 10/100 Mbps PCI Ethernet Controller
• Manufacturer: Advanced Micro Devices

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
8/01/00
SWSTYLE
BCR20[7:
0]
0
2
3
4
5
Table 5. Descriptor Write Sequence
AD Bus Sequence
for Rx Descriptor
Address = XXXX
XX04h
Data
Idle
Address = XXXX
XX00h
Data
Address = XXXX
XX08h
Data
Idle
Address = XXXX
XX04h
Data
Address = XXXX
XX00h
Data
Data
Address = XXXX
XX00h
Data
Address = XXXX
XX00h
Data
AD Bus Sequence
for Tx Descriptor
Address = XXXX
XX04h
Data
Idle
Address = XXXX
XX00h
Data
Address = XXXX
XX08h
Data
Idle
Address = XXXX
XX04h
Data
Address = XXXX
XX00h
Data
Data
Address = XXXX
XX00h
Data
Address = XXXX
XX00h
Data
P R E L I M I N A R Y
Am79C976
was programmed to use 16-bit software structures
(SWSTYLE = 0).
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