AM79C971VCW Advanced Micro Devices, AM79C971VCW Datasheet - Page 106

• Manufacturer Part Number: AM79C971VCW
• Description: PCnet-FAST Single-Chip Full-Duplex 10/100 Mbps Ethernet Controller for PCI Local Bus
• Manufacturer: Advanced Micro Devices

106
Table 25. Legal I/O Accesses in Double Word I/O
AD[4:0] BE[3:0]
Table 24. I/O Map In DWord I/O Mode (DWIO = 1)
0XX00
0XX00
10000
10100
11000
11100
10000
10100
11000
11100
00h - 0Fh
AD[4:0]
0XX00
0XX01
0XX10
0XX11
0XX00
0XX10
0XX00
0XX10
10000
10010
10100
10110
10000
10010
10100
10110
10000
Offset
1Ch
10h
14h
18h
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
No. of Bytes
BE[3:0]
1110
1101
1011
0111
1100
0011
1100
0011
1100
0011
1100
0011
1100
0011
1100
0011
0000
Mode (DWIO =1)
Type
16
4
4
4
4
WR
WR
WR
WR
WR
RD
RD
RD
RD
RD
Table 23. Legal I/O Accesses in Word I/O Mode (DWIO = 0)
Comment
DWord read of APROM
locations 3h (MSB) to 0h (LSB),
7h to 4h, Bh to 8h or Fh to Ch
DWord read of RDP
DWord read of RAP
DWord read of Reset Register
DWord read of BDP
DWord write to APROM
locations 3h (MSB) to 0h (LSB),
7h to 4h, Bh to 8h or Fh to Ch
DWord write to RDP
DWord write to RAP
DWord write to Reset Register
DWord write of BDP
APROM
RDP
RAP (shared by RDP and
BDP)
Reset Register
BDP
Type
WR
WR
WR
WR
WR
WR
WR
RD
RD
RD
RD
RD
RD
RD
RD
RD
RD
Register
Byte read of APROM location 0h, 4h, 8h or Ch
Byte read of APROM location 1h, 5h, 9h or Dh
Byte read of APROM location 2h, 6h, Ah or Eh
Byte read of APROM location 3h, 7h, Bh or Fh
Word read of APROM locations 1h (MSB) and 0h (LSB), 5h and 4h, 8h and 9h or
Ch and Dh
Word read of APROM locations 3h (MSB) and 2h (LSB), 7h and 6h, Bh and Ah or
Fh and Eh
Word read of RDP
Word read of RAP
Word read of Reset Register
Word read of BDP
Word write to APROM locations 1h (MSB) and 0h (LSB), 5h and 4h, 8h and 9h or
Ch and Dh
Word write to APROM locations 3h (MSB) and 2h (LSB), 7h and 6h, Bh and Ah or
Fh and Eh
Word write to RDP
Word write to RAP
Word write to Reset Register
Word write to BDP
DWord write to RDP,
switches device to DWord I/O mode
Am79C971
USER ACCESSIBLE REGISTERS
The Am79C971 controller has three types of user reg-
isters: the PCI configuration registers, the Control and
Status registers (CSR), and the Bus Control registers
(BCR).
The Am79C971 controller implements all PCnet-ISA
(Am79C960) registers, all C-LANCE (Am79C90) regis-
ters, plus a number of additional registers. The
Am79C971 controller CSRs are compatible upon
power up with both the PCnet-ISA CSRs and all of the
C-LANCE CSRs.
The PCI configuration registers can be accessed in any
data width. All other registers must be accessed ac-
cording to the I/O mode that is currently selected.
When WIO mode is selected, all other register loca-
tions are defined to be 16 bits in width. When DWIO
mode is selected, all these register locations are de-
fined to be 32 bits in width, with the upper 16 bits of
most register locations marked as reserved locations
with undefined values. When performing register write
operations in DWIO mode, the upper 16 bits should al-
ways be written as zeros. When performing register
read operations in DWIO mode, the upper 16 bits of I/
O resources should always be regarded as having un-
defined values, except for CSR88.
The Am79C971 registers can be divided into four
groups: PCI Configuration, Setup, Running, and Test.
Registers not included in any of these categories can
be assumed to be intended for diagnostic purposes.
Comment