MC68HC908GT16_07 FREESCALE [Freescale Semiconductor, Inc], MC68HC908GT16_07 Datasheet - Page 184

• Manufacturer Part Number: MC68HC908GT16_07
• Description: Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

System Integration Module (SIM)
At power-on, these events occur:
15.3.2.2 Computer Operating Properly (COP) Reset
An input to the SIM is reserved for the COP reset signal. The overflow of the COP counter causes an
internal reset and sets the COP bit in the SIM reset status register (SRSR). The SIM actively pulls down
the RST pin for all internal reset sources.
The COP module is disabled if the RST pin or the IRQ pin is held at V
mode. The COP module can be disabled only through combinational logic conditioned with the high
voltage signal on the RST or the IRQ pin. This prevents the COP from becoming disabled as a result of
external noise. During a break state, V
15.3.2.3 Illegal Opcode Reset
The SIM decodes signals from the CPU to detect illegal instructions. An illegal instruction sets the ILOP
bit in the SIM reset status register (SRSR) and causes a reset.
If the stop enable bit, STOP, in the CONFIG1 register is 0, the SIM treats the STOP instruction as an
illegal opcode and causes an illegal opcode reset. The SIM actively pulls down the RST pin for all internal
reset sources.
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A POR pulse is generated.
The internal reset signal is asserted.
The SIM enables CGMOUT.
Internal clocks to the CPU and modules are held inactive for 4096 CGMXCLK cycles to allow
stabilization of the oscillator.
The RST pin is driven low during the oscillator stabilization time.
The POR bit of the SIM reset status register (SRSR) is set and all other bits in the register are
cleared.
CGMXCLK
CGMOUT
PORRST
OSC1
IRST
RST
IAB
MC68HC908GT16 • MC68HC908GT8 • MC68HC08GT16 Data Sheet, Rev. 5.0
CYCLES
4096
Figure 15-7. POR Recovery
TST
CYCLES
32
on the RST pin disables the COP module.
CYCLES
32
TST
$FFFE
while the MCU is in monitor
Freescale Semiconductor
$FFFF