Emulator Support Signals; Cache Disable (Cdis); Mmu Disable (Mmudis); Pipeline Refill (Refill) - Motorola MC68030 User Manual

Signal Description

5.11 EMULATOR SUPPORT SIGNALS

The following signals support emulation by providing a means for an emulator to disable the
on-chip caches and memory management unit and by supplying internal status information
to an emulator. Refer to Section 12 Applications Information for more detailed
information on emulation support.

5.11.1 Cache Disable (CDIS)

The cache disable signal dynamically disables the on-chip caches to assist emulator
support. Refer to 6.1 On-Chip Cache Organization and Operation for information about
the caches; refer to Section 12 Applications Information for a description of the use of
this signal by an emulator. CDIS does not flush the data and instruction caches; entries
remain unaltered and become available again when CDIS is negated.

5.11.2 MMU Disable (MMUDIS)

The MMU disable signal dynamically disables the translation of addresses by the MMU.
Refer to 9.4 Address Translation Cache for a description of address translation; refer to
Section 12 Applications Information for a description of the use of this signal by an
emulator. The assertion of MMUDIS does not flush the address translation cache (ATC);
ATC entries become available again when MMUDIS is negated.

5.11.3 Pipeline Refill (REFILL)

The pipeline refill signal indicates that the MC68030 is beginning to refill the internal
instruction pipeline. Refer to Section 12 Applications Information for a description of the
use of this signal by an emulator.

5.11.4 Internal Microsequencer Status (STATUS)

The microsequencer status signal indicates the state of the internal microsequencer. The
varying number of clocks for which this signal is asserted indicates instruction boundaries,
pending exceptions, and the halted condition. Refer to Section 12 Applications
Information for a description of the use of this signal by an emulator.
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