SIM Registers
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.
Address:
$FE01
Bit 7
6
5
4
3
2
1
Bit 0
0
Read:
Write:
Reset:
POR
PIN
COP
ILOP
ILAD
MODRST
LVI
1
0
0
0
0
0
0
0
= Unimplemented
Figure 7-21. SIM Reset Status Register (SRSR)
POR — Power-On Reset Bit
1 = Last reset caused by POR circuit
0 = Read of SRSR
PIN — External Reset Bit
1 = Last reset caused by external reset pin (RST)
0 = POR or read of SRSR
COP — Computer Operating Properly Reset Bit
1 = Last reset caused by COP counter
0 = POR or read of SRSR
ILOP — Illegal Opcode Reset Bit
1 = Last reset caused by an illegal opcode
0 = POR or read of SRSR
ILAD — Illegal Address Reset Bit (opcode fetches only)
1 = Last reset caused by an opcode fetch from an illegal address
0 = POR or read of SRSR
MODRST — Monitor Mode Entry Module Reset Bit
1 = Last reset caused by monitor mode entry when vector locations $FFFE and $FFFF are $FF after
POR while IRQ1 = V
DD
0 = POR or read of SRSR
LVI — Low-Voltage Inhibit Reset Bit
1 = Last reset caused by the LVI circuit
0 = POR or read of SRSR
MC68HC908AP Family Data Sheet, Rev. 4
Freescale Semiconductor
113
FREESCALE [ Freescale ]
