am79c930 Advanced Micro Devices, am79c930 Datasheet - Page 59

• Manufacturer Part Number: am79c930
• Description: Pcnet-mobile Single-chip Wireless Lan Media Access Controller
• Manufacturer: Advanced Micro Devices

The I/O range is adjusted through bit 2 (EIOW = Expand
I/O Window) of SIR1 = Bank Switching Select register).
Note that since the Am79C930 device’s memory
mapped resources are all accessible through the Local
Memory Address Register and I/O Data Ports
(SIR2,3,4,5,6,7), it is possible to assign the Am79C930
device no memory space. (This is accomplished by
setting the MemSpace field of the TPCE_FS byte of
the Configuration Table Entry Tuple to 00b. This will
inform the PCMCIA configuration utility that the
Am79C930-based design does not require any Com-
mon Memory space.) By assigning no memory space to
the Am79C930 device, the Am79C930 device will
become an I/O only device. Such an arrangement may
be convenient for systems in which there is not enough
total available memory space to allow the Am79C930
device to use a full 32K block of memory.
Note that when this option is chosen, the total amount of
bus bandwidth required to perform all of the necessary
accesses to the Am79C930-based design will be in-
creased somewhat, because of the indirect nature of the
I/O method of access to Am79C930-based resources.
Note that the Am79C930 device always decodes
the lowest 6 bits of address when an I/O access is
Memory Range
0000h – 7FFFh
PCMCIA Address in
Common
Common Memory
0000h – 7FFFh
0000h – 7FFFh
0000h – 7FFFh
0000h – 7FFFh
0000h – 7FFFh
0000h – 7FFFh
0000h – 7FFFh
0000h – 7FFFh
Memory Size
Am79C930 Device PCMCIA Mode Resource Requirements
Common
32 Kbytes
Am79C930 Device PCMCIA Mode Common Memory Map
0 bytes
OR
SIR1[5:3]
TOTAL:
000
010
011
100
101
110
111
001
0000h – 000Fh
0000h – 0027h
I/O Range
P R E L I M I N A R Y
OR
Am79C930
Size of Space
256 Kbytes
32 Kbytes
32 Kbytes
32 Kbytes
32 Kbytes
32 Kbytes
32 Kbytes
32 Kbytes
32 Kbytes
performed with the Am79C930 device’s CE1 signal ac-
tive. This means that there is aliasing of addresses in I/O
space. This decode function is unaffected by the setting
of the SIR1[2:0] register bits.
PCMCIA Common Memory Resources — While the
common memory space of the Am79C930 device only
accommodates access to 32 Kbytes of memory, the
Am79C930 device uses device select and bank select
bits in SIR1 in order to access a total of 256K of memory
space. Note that PCMCIA accesses to Common mem-
ory locations 7C00h–7FFFh (1K total space) will some-
times correspond to the same physical locations as
PCMCIA accesses to Attribute memory locations
0000h–07FFh (2K total space), i.e., the correspon-
dence will occur only when the device and bank select
bits of SIR1 are pointing at the upper page of the 128K
Flash memory address space. (Note that for Attribute
memory accesses, only the even-valued addresses are
defined to exist. Therefore, 2K total Attribute memory
addresses have been mapped to 1K of physical space in
the Flash memory.) The following table indicates the
mapping of the 256 Kbytes of physical memory space
into the 32 Kbytes of Common memory:
I/O Size
bytes
OR
40
16
Memory Range
0000h – 0803h
SRAM Memory 0 0000h – 0 7FFFh
SRAM Memory 0 8000h – 0 FFFFh
SRAM Memory 1 0000h – 1 7FFFh
SRAM Memory 1 8000h – 1 FFFFh
Flash Memory 0 0000h – 0 7FFFh
Flash Memory 0 8000h – 0 FFFFh
Flash Memory 1 0000h – 1 7FFFh
Flash Memory 1 8000h – 1 FFFFh
Attribute
Physical Memory
Memory Size
2 K+4 bytes
Attribute
AMD
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