MC68HC705JD FREESCALE [Freescale Semiconductor, Inc], MC68HC705JD Datasheet - Page 31

• Manufacturer Part Number: MC68HC705JD
• Description: member of the low-cost
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

5.1 Resets
5.1.1 Power-On Reset
Rev. 2
This section describes how resets reinitialize the MCU and how interrupts temporarily
change the normal processing sequence.
A reset immediately stops the operation of the instruction being executed. A reset
initializes certain control bits to known conditions and loads the program counter with
a user-defined reset vector address. The following conditions produce a reset:
A reset does the following things to reinitialize the MCU:
A positive transition on the V
is strictly for power-up conditions and cannot be used to detect drops in power supply
voltage.
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Initial power-up (power-on reset)
A logical zero applied to the RESET pin (external reset)
Timeout of the COP timer (COP reset)
An opcode fetch from an address not in the memory map (illegal address reset)
Clears all implemented data direction register bits so that the corresponding
I/O pins are inputs
Loads the stack pointer with $FF
Sets the interrupt mask, inhibiting interrupts
Clears the TOFE and RTIE bits in the timer control and status register
Clears the STOP latch, enabling the CPU clocks
Clears the WAIT latch, waking the CPU from the WAIT mode
Loads the program counter with the user-defined reset vector
Freescale Semiconductor, Inc.
For More Information On This Product,
RESETS AND INTERRUPTS
RESETS AND INTERRUPTS
Go to: www.freescale.com
DD
pin generates a power-on reset. The power-on reset
SECTION 5
5-1
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