mc68hc908lb8 Freescale Semiconductor, Inc, mc68hc908lb8 Datasheet - Page 165

• Manufacturer Part Number: mc68hc908lb8
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

16.2.4 System Integration Module (SIM) Reset Status Register
This read-only register contains flags to show reset sources. All flag bits are automatically cleared
following a read of the register. Reset service can read the SIM reset status register to clear the register
after power-on reset and to determine the source of any subsequent reset.
The register is initialized on power-up as shown with the POR bit set and all other bits cleared. During a
POR or any other internal reset, the RST pin is pulled low as long as pin PTA5/RST/KB5 is configured for
reset operation.
POR — Power-On Reset Flag
PIN — External Reset Flag
COP — Computer Operating Properly Reset Bit
ILOP — Illegal Opcode Reset Bit
ILAD — Illegal Address Reset Bit
MODRST — Monitor Mode Entry Module Reset Bit
LVI — Low-Voltage Inhibit Reset Bit
Freescale Semiconductor
1 = Power-on reset since last read of SRSR
0 = Read of SRSR since last power-on reset
1 = External reset via RST pin since last read of SRSR
0 = POR or read of SRSR since last external reset
1 = Last reset caused by timeout of COP counter
0 = POR or read of SRSR since any reset
1 = Last reset caused by an illegal opcode
0 = POR or read of SRSR since any reset
1 = Last reset caused by an opcode fetch from an illegal address
0 = POR or read of SRSR since any reset
1 = Last reset caused by forced monitor mode entry.
0 = POR or read of SRSR since any reset
1 = Last reset caused by low-power supply voltage
0 = POR or read of SRSR since any reset
Address:
Only a read of the SIM reset status register clears all reset flags. After
multiple resets from different sources without reading the register, multiple
flags remain set.
Read:
Write:
POR:
$FE01
POR
Bit 7
1
Figure 16-2. SIM Reset Status Register (SRSR)
= Unimplemented
PIN
6
0
MC68HC908LB8 Data Sheet, Rev. 1
COP
5
0
NOTE
ILOP
4
0
ILAD
3
0
MODRST
2
0
LVI
1
0
Bit 0
0
0
Resets
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