M69030 Asiliant Technologies, M69030 Datasheet - Page 63

• Manufacturer Part Number: M69030
• Manufacturer: Asiliant Technologies

Specifications of M69030

• Operating Temperature (min): 0C
• Operating Temperature Classification: Commercial
• Operating Temperature (max): 70C
• Rad Hardened: No
• Lead Free Status / Rohs Status: Supplier Unconfirmed

I/O and Memory Address Maps
5-9
Two-Way Sub-Indexed Register Indices
Using the previously described I/O and memory space shadowing schemes, it is possible to access the 8-
bit registers (IOSS, MSS, FCR, MSR, ST00, ST01, ARxx, CRxx, FRxx, GRxx, MRxx, XRxx, and DAC
registers) in three ways -- i.e., via the I/O register space and via both the pipeline A and pipeline B portions
of the memory-mapped register space. To prevent conflicts between incarnations of driver code, as well as
other software, separate sets of indices, one for pipeline A and the other for pipeline B, are used in
accessing the 8-bit sub-indexed registers (i.e., ARxx, CRxx, FRxx, GRxx, MRxx and XRxx).
With the upper memory map set to the appropriate mode, pipeline A has its own dedicated range of
addresses (offsets 400000 through 7FFFFFh) in the memory-mapped register space, and all accesses
made to the sub-indexed registers through that memory space make use of set A of the sub-indexed register
indices. Likewise, pipeline B also has its own dedicated range of addresses (offsets C00000h to FFFFFFh)
in the memory-mapped register space, and all accesses made to the sub-indexed registers through it make
use of set B of the sub-indexed register indices. This tying of the use of one or the other set of sub-indexed
register indices to the choice of memory space used in making a given access is maintained, regardless of
how the MSS register is set.
Accesses made to the sub-indexed registers via the I/O space can be made to use one or the other of either
set A or set B of the sub-indexed register indices. The IOSS register provides the means of selecting one
or both of these sets of indices to be used as appropriate in such accesses.
`efmp
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69030 Databook
Revision 1.3 11/24/99