mc68hc908ap8a Freescale Semiconductor, Inc, mc68hc908ap8a Datasheet - Page 113

• Manufacturer Part Number: mc68hc908ap8a
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

7.7.2 SIM Reset Status Register
This register contains six flags that show the source of the last reset provided all previous reset status
bits have been cleared. Clear the SIM reset status register by reading it. A power-on reset sets the POR
bit and clears all other bits in the register.
The register is initialized on power up with the POR bit set and all other bits cleared. During a POR or any
other internal reset, the RST pin is pulled low. After the pin is released, it will be sampled 32 CGMXCLK
cycles later. If the pin is not above V
other bits are set.
POR — Power-On Reset Bit
PIN — External Reset Bit
COP — Computer Operating Properly Reset Bit
ILOP — Illegal Opcode Reset Bit
ILAD — Illegal Address Reset Bit (opcode fetches only)
MODRST — Monitor Mode Entry Module Reset Bit
LVI — Low-Voltage Inhibit Reset Bit
Freescale Semiconductor
1 = Last reset caused by POR circuit
0 = Read of SRSR
1 = Last reset caused by external reset pin (RST)
0 = POR or read of SRSR
1 = Last reset caused by COP counter
0 = POR or read of SRSR
1 = Last reset caused by an illegal opcode
0 = POR or read of SRSR
1 = Last reset caused by an opcode fetch from an illegal address
0 = POR or read of SRSR
1 = Last reset caused by monitor mode entry when vector locations $FFFE and $FFFF are $FF after
0 = POR or read of SRSR
1 = Last reset caused by the LVI circuit
0 = POR or read of SRSR
POR while IRQ1 = V
Address:
Reset:
Read:
Write:
$FE01
POR
Bit 7
1
Figure 7-21. SIM Reset Status Register (SRSR)
= Unimplemented
DD
PIN
MC68HC908AP A-Family Data Sheet, Rev. 3
6
0
IH
at this time, then the PIN bit may be set, in addition to whatever
COP
5
0
ILOP
4
0
ILAD
3
0
MODRST
2
0
LVI
1
0
Bit 0
0
0
SIM Registers
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