XC68HC705JJ7 Motorola, XC68HC705JJ7 Datasheet - Page 66

• Manufacturer Part Number: XC68HC705JJ7
• Description: MICROCONTROLLER
• Manufacturer: Motorola

Resets
5.2 Introduction
Advance Information
66
RESET
V
DD
MASK OPTION REGISTER ($1FF1)
ILLEGAL ADDRESS RESET
This section describes the five reset sources and how they initialize the
microcontroller unit (MCU). A reset immediately stops the operation of
the instruction being executed, initializes certain control bits, and loads
the program counter with a user-defined reset vector address. These
conditions produce a reset:
Figure 5-1
interaction.
LOW-VOLTAGE RESET
POWER-ON RESET
COP WATCHDOG
CLOCKED
•
•
•
•
•
3-CYCLE
1-SHOT
Initial power-up of device (power-on reset)
A logic 0 applied to the RESET pin (external reset)
Timeout of the computer operating properly (COP) watchdog
(COP reset)
Low voltage applied to the device (LVR reset)
Fetch of an opcode from an address not in the memory map
(illegal address reset)
Figure 5-1. Reset Sources
shows a block diagram of the reset sources and their
INTERNAL
ADDRESS BUS
INTERNAL DATA BUS
Resets
MC68HC705JJ7 • MC68HC705JP7 — REV 4
D
RESET
LATCH
R
S
RST
TO CPU
AND
SUBSYSTEMS
INTERNAL
CLOCK
MOTOROLA