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AMD
65Am79C930
address needs to be aligned to a 32K boundary in mem-
ory space. This alignment requirement should be in-
cluded in the Resource Data that is programmed into the
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 Size of Physical Memory And
in Memory SIR1[5:3] Restricted Space Description Of Reserved Use
MBA+0000h – 000 1 Kbytes SRAM Memory 0 0000h–0 03FFh
MBA+03FFh This space is reserved for the interrupt vector
table of the embedded 80188 core.
MBA+0400h – 000 32 bytes SRAM Memory 0 0400h–0 041Fh
MBA+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 – 000 32 bytes SRAM Memory 0 0420h–0 042Fh
MBA+043Fh 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 – 000 64 bytes SRAM Memory 0 0440h–0 047Fh
MBA+047Fh This SRAM space is reserved for future use
and may be decoded for non-SRAM purposes
in the future.
MBA+7C00h – 111 1K–16 bytes Flash Memory 1 FC00h–1 FFEFh
MBA+7FEFh 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 – 111 16 bytes Flash Memory 1 FFF0h–1 FFFFh
MBA+7FFFh 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