AM79C978 Advanced Micro Devices, AM79C978 Datasheet - Page 61

• Manufacturer Part Number: AM79C978
• Description: Single-Chip 1/10 Mbps PCI Home Networking Controller
• Manufacturer: Advanced Micro Devices

Figure 33 illustrates the relationship between the initial-
ization base address, the initialization block, the re-
ceive and transmit descriptor ring base addresses, the
receive and transmit descriptors, and the receive and
transmit data buffers, when SSIZE32 is cleared to 0.
Note that the value of CSR2, bits 15-8, is used as the
upper 8-bits for all memory addresses during bus mas-
ter transfers.
TLE
RLE
IADR[31:16]
CSR2
Initialization
LADRF[47:32]
LADRF[63:48]
LADRF[31:16]
RES
RES
LADRF[15:0]
PADR[31:16]
PADR[47:32]
RDRA[15:0]
PADR[15:0]
TDRA[15:0]
Block
MOD
TDRA[23:16]
RDRA[23:16]
IADR[15:0]
CSR1
Figure 33. 16-Bit Software Model
Buffers
Buffers
Xmt
Rcv
Am79C978
1st desc.
start
1st desc.
start
RMD
Figure 34 illustrates when SSIZE32 is set to 1, the re-
lationship between the initialization base address, the
initialization block, the receive and transmit descriptor
ring base addresses, the receive and transmit descrip-
tors, and the receive and transmit data buffers.
TMD
Buffer
Buffer
Data
Data
1
1
RMD
N
Rcv Descriptor
TMD
M
Xmt Descriptor
Ring
RMD
Buffer
Buffer
N
TMD
Data
Data
Ring
2
2
M
RMD
N
TMD
M
2nd
desc.
2nd
desc.
RMD0
N
TMD
M
•
Buffer
Buffer
Data
Data
•
•
M
N
•
•
•
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