MC68020 Motorola, MC68020 Datasheet - Page 42
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MC68020
Manufacturer Part Number
MC68020
Description
(MC68020 / MC68EC020) MICROPROCESSORS USERS MANUAL
Manufacturer
Motorola
Datasheet
1.MC68020.pdf
(306 pages)
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Halt (HALT)
Bus Error (BERR)
3.10 EMULATOR SUPPORT SIGNAL
The following signal supports emulation by providing a means for an emulator to disable
the on-chip cache by supplying internal status information to an emulator. Refer to
Section 7 Coprocessor Interface Description for more detailed information on
emulation support.
Cache Disable (CDIS)
3.11 CLOCK (CLK)
The CLK signal is the clock input to the MC68020/EC020. This TTL-compatible signal
should not be gated off at any time while power is applied to the processor. Refer to
Section 9 Applications Information for suggestions on clock generation. Refer to
Section 10 Electrical Characteristics for electrical characteristics.
3.12 POWER SUPPLY CONNECTIONS
The MC68020/EC020 requires connection to a V
ground. The V
sections of the processor. The ground connections are similarly grouped. Section 11
Ordering Information and Mechanical Data describes the groupings of V
connections, and Section 9 Applications Information describes a typical power supply
interface.
MOTOROLA
The assertion of this bidirectional open-drain signal indicates that the processor should
suspend bus activity or, when used with BERR , that the processor should retry the
current cycle. Refer to Section 5 Bus Operation for a description of the effects of
HALT on bus operations. When the processor has stopped executing instructions due
to a double bus fault condition, the HALT line is asserted by the processor to indicate to
external devices that the processor has stopped.
This input signal indicates that an invalid bus operation is being attempted or, when
used with HALT , that the processor should retry the current cycle. Refer to Section 5
Bus Operation for a description of the effects of BERR on bus operations.
This input signal statically disables the on-chip cache to assist emulator support. Refer
to Section 4 On-Chip Cache Memory for information about the cache; refer to Section
9 Applications Information for a description of the use of this signal by an emulator.
CDIS does not flush the instruction cache; entries remain unaltered and become
available again when CDIS is negated.
CC
connections are grouped to supply adequate current for the various
M68020 USER’S MANUAL
CC
power supply, positive with respect to
CC
and ground
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