mc68hc08ln56 Freescale Semiconductor, Inc, mc68hc08ln56 Datasheet - Page 64

• Manufacturer Part Number: mc68hc08ln56
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

System Integration Module (SIM)
5.3 Reset and System Initialization
The MCU has these reset sources:
All of these resets produce the vector $FFFE:FFFF ($FEFE:FEFF in monitor mode) and assert the
internal reset signal (IRST). IRST causes all registers to be returned to their default values and all
modules to be returned to their reset states.
An internal reset clears the SIM counter (see
the resets sets a corresponding bit in the SIM reset status register (SRSR). (See
5.3.1 External Pin Reset
Pulling the asynchronous RST pin low halts all processing. The PIN bit of the SIM reset status register
(SRSR) is set as long as RST is held low for a minimum of 67 CGMXCLK cycles, assuming that neither
the POR nor the LVI was the source of the reset. See
timing.
5.3.2 Active Resets from Internal Sources
All internal reset sources actively pull the RST pin low for 32 CGMXCLK cycles to allow resetting of
external peripherals. The internal reset signal IRST continues to be asserted for an additional 32 cycles.
See
or POR. (See
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
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Figure
Power-on reset module (POR)
External reset pin (RST)
Computer operating properly module (COP)
Low-voltage inhibit module (LVI)
Illegal opcode
Illegal address
CGMOUT
RST
5-5. An internal reset can be caused by an illegal address, illegal opcode, COP timeout, LVI,
IAB
Figure
PC
MC68HC08LN56 • MC68HC708LN56 General Release Specification, Rev. 2.1
Reset Type
All others
POR/LVI
5-6.) Note that for LVI or POR resets, the SIM cycles through 4096 CGMXCLK
Figure 5-4. External Reset Timing
Table 5-2. PIN Bit Set Timing
Figure
5.4 SIM
5-5.
Number of Cycles Required to Set PIN
Table 5-2
Counter), but an external reset does not. Each of
4163 (4096 + 64 + 3)
67 (64 + 3)
VECT H
for details.
VECT L
Figure 5-4
5.7 SIM
Freescale Semiconductor
shows the relative
Registers.)