MC68HC000RC12 Freescale Semiconductor, MC68HC000RC12 Datasheet - Page 74

• Manufacturer Part Number: MC68HC000RC12
• Description: IC MPU 32BIT 12MHZ 68-PGA
• Manufacturer: Freescale Semiconductor

Specifications of MC68HC000RC12

• Processor Type: M680x0 32-Bit
• Speed: 12MHz
• Voltage: 3.3V, 5V
• Mounting Type: Surface Mount
• Package / Case: 68-PGA
• Family Name: M68000
• Device Core: ColdFire
• Device Core Size: 16/32Bit
• Frequency (max): 12MHz
• Instruction Set Architecture: RISC
• Supply Voltage 1 (typ): 5V
• Operating Supply Voltage (max): 5.25V
• Operating Supply Voltage (min): 4.75V
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Through Hole
• Pin Count: 68
• Package Type: PGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Lead Free Status / Rohs Status: Compliant

While the processor is halted, the address bus and the data bus signals are placed in the
high-impedance state. Bus arbitration is performed as usual. Should a bus error occur
while HALT is asserted, the processor performs the retry operation previously described.
The single-step mode is derived from correctly timed transitions of HALT. HALT is negated
to allow the processor to begin a bus cycle, then asserted to enter the halt mode when the
cycle completes. The single-step mode proceeds through a program one bus cycle at a
time for debugging purposes. The halt operation and the hardware trace capability allow
tracing of either bus cycles or instructions one at a time. These capabilities and a software
debugging package provide total debugging flexibility.
5.4.4 Double Bus Fault
When a bus error exception occurs, the processor begins exception processing by
stacking information on the supervisor stack. If another bus error occurs during exception
processing (i.e., before execution of another instruction begins) the processor halts and
asserts HALT. This is called a double bus fault. Only an external reset operation can
restart a processor halted due to a double bus fault.
A retry operation does not initiate exception processing; a bus error during a retry
operation does not cause a double bus fault. The processor can continue to retry a bus
cycle indefinitely if external hardware requests.
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FC2–FC0
D0–D15
A23–A1
DTACK
BERR
HALT
UDS
LDS
R/W
CLK
AS
S0
M68000 8-/16-/32-BIT MICROPROCESSORS USER'S MANUAL
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Figure 5-29. Halt Operation Timing Diagram
Freescale Semiconductor, Inc.
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HALT
S0
S2
RETRY
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