TS68020 ATMEL Corporation, TS68020 Datasheet - Page 24

• Manufacturer Part Number: TS68020
• Description: Hcmos 32-bit Virtual Memory Mpu, 16/20/25 MHZ
• Manufacturer: ATMEL Corporation

The TS68000 Family processors distinguish address spaces as supervisor / used and
program/data. These four combinations are specified by the function code pins
(FC0/FC1/FC2) during bus cycles, indication the particular address space. Using the
function codes, the memory sub-system can distinguish between authorized access
(supervisor mode is privileged access) and unauthorized access (user mode may not
have access to supervisor program or data areas). To support the full privileges of the
supervisor, the alternate function code registers allow the supervisor to specify an
access to user program or data a re as by prelo ading the SFC/DFC registers
appropriately.
The cache registers (control — CACR, address — CAAR) allow software manipulation
of the on-chip instruction cache. Control and status accesses to the instruction cache
are provided by the cache control register (CACR), while the cache address register
(CAAR) holds the address for those cache control functions that require an address.
Figure 19. User Programming Model
TS68020
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2115A–HIREL–07/02