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P R E L I M I N A R Y
address needs to be aligned to a 32K boundary in mem-
ory space. This alignment requirement should be in-
cludedintheResourceDatathatisprogrammedintothe
Flash device and read by the Plug and Play configura-
tion utility. These conditions must be satisfied, since the
Am79C930 device’s Bus Interface Unit will only use the
upper 9 bits of the ISA memory address to determine
when an address match has been achieved.
Some of the Am79C930 device’s ISA Memory locations
have predefined uses and, therefore, are not freely
available to the device driver. The following table indi-
cates restricted space within ISA Memory map of the
Am79C930 device:
Am79C930 Device ISA Plug And Play Mode Memory Restricted Space
ISA Address
in Memory
Size of
Restricted Space
Physical Memory And
Description Of Reserved Use
SIR1[5:3]
MBA+0000h –
MBA+03FFh
000
1 Kbytes
SRAM Memory 0 0000h–0 03FFh
This space is reserved for the interrupt vector
table of the embedded 80188 core.
MBA+0400h –
MBA+041Fh
000
000
32 bytes
SRAM Memory 0 0400h–0 041Fh
This SRAM space is inaccessible to the
80188 embedded core, since the 80188
core maps the 32 TIR registers of the TAI
into this portion of 80188 memory space.
MBA+0420h –
MBA+043Fh
32 bytes
SRAM Memory 0 0420h–0 042Fh
This SRAM space is inaccessible to the
80188 embedded core, since the 80188
core maps the MIR registers of the BIU
(PIR, PDLC and PUCT) and XCE space into
this portion of 80188 memory space.
MBA+0440h –
MBA+047Fh
000
111
64 bytes
SRAM Memory 0 0440h–0 047Fh
This SRAM space is reserved for future use
and may be decoded for non-SRAM purposes
in the future.
MBA+7C00h –
MBA+7FEFh
1K–16 bytes
Flash Memory 1 FC00h–1 FFEFh
These bytes of the Flash memory also map into
the ISA Plug and Play Resource Data space.
Therefore, this space can not be used for
non-Resource Data purposes.
MBA+7FF0h –
MBA+7FFFh
111
16 bytes
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.
*MBA = ISA Plug and Play Memory Base Address
Am79C930
65
AMD [ AMD ]
