mc68hc908jb8 Freescale Semiconductor, Inc, mc68hc908jb8 Datasheet - Page 99

• Manufacturer Part Number: mc68hc908jb8
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

8.4.2 Active Resets from Internal Sources
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3
Freescale Semiconductor
NOTE:
All internal reset sources actively pull the RST pin low for 32 OSCXCLK
cycles to allow resetting of external peripherals. The internal reset signal
IRST continues to be asserted for an additional 32 cycles. (See Figure
8-5.) An internal reset can be caused by an illegal address, illegal
opcode, COP timeout, LVI, the USB module or POR. (See
Sources of Internal
For LVI or POR resets, the SIM cycles through 4096 OSCXCLK cycles
during which the SIM forces the RST pin low. The internal reset signal
then follows the sequence from the falling edge of RST shown in
Figure
The COP reset is asynchronous to the bus clock.
The active reset feature allows the part to issue a reset to peripherals
and other chips within a system built around the MCU.
OSCXCLK
IRST
RST
IAB
8-5.
System Integration Module (SIM)
Figure 8-6. Sources of Internal Reset
ILLEGAL ADDRESS RST
RST PULLED LOW BY MCU
Figure 8-5. Internal Reset Timing
ILLEGAL OPCODE RST
Reset.)
32 CYCLES
COPRST
POR
USB
LVI
INTERNAL RESET
System Integration Module (SIM)
32 CYCLES
Reset and System Initialization
VECTOR HIGH
Figure 8-6 .
Technical Data
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