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AMD
Am79C930 Device PCMCIA Mode Attribute Memory Restricted Space
PCMCIA Address
in Attribute Memory SIR1[5:3] Size of Restricted Space
7FE0h – 7FFFh
PCMCIA I/O Resources — The Am79C930 device oc-
cupies either 16 or 40 bytes of I/O space, depending
upon the setting of the EIOW bit (bit 2 of the BSS register
(SIR1)). The I/O space of the Am79C930 contains the
General Configuration Register, the Bank Switching Se-
lect Register, and the set of 32 TIR registers. Addition-
ally, all Am79C930 resources are accessible through
I/O accesses, i.e., all memory structures are accessible
through the Local Memory Address and I/O Data
Ports (SIR2,3,4,5,6,7).
The Local Memory Address port plus SIR1[5:3] function
together as a pointer to the memory resources of the
Am79C930 device. SIR1[5] determines the device
62
P R E L I M I N A R Y
111
32 bytes of Attribute
memory, 16 bytes of actual
Flash memory space
Physical Memory and Description of Reserved Use
Flash Memory 1 FFF0h – 1 FFFFh
These 16 bytes of Flash memory space are reserved
because they are the location of the embedded 80188
core's instruction pointer following a Am79C930 device
reset operation. These 16 bytes must contain the first 80188
instructions.
selected (SRAM or Flash), and SIR1[4:3] and
LMA[14:0] supply the address to the selected device
whenever the I/O Data Port is read or written. Whenever
any of the I/O Data Ports is accessed, then the Local
Memory Address Port value is automatically incre-
mented by a value of "1."
Note that the Am79C930 device always decodes the
lowest 6 bits of address when an I/O access is per-
formed with the Am79C930 device's CE1 signal active.
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.
Am79C930
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