mc68hc908qb4 Freescale Semiconductor, Inc, mc68hc908qb4 Datasheet - Page 152

• Manufacturer Part Number: mc68hc908qb4
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

System Integration Module (SIM)
The SIM counter is held in reset from the execution of the STOP instruction until the beginning of stop
recovery. It is then used to time the recovery period.
Figure 14-18
14.8 SIM Registers
The SIM has two memory mapped registers.
14.8.1 SIM Reset Status Register
The SRSR register contains flags that show the source of the last reset. The status register will
automatically clear after reading SRSR. A power-on reset sets the POR bit and clears all other bits in the
register. All other reset sources set the individual flag bits but do not clear the register. More than one
reset source can be flagged at any time depending on the conditions at the time of the internal or external
reset. For example, the POR and LVI bit can both be set if the power supply has a slow rise time.
152
ADDRESS BUS
INTERRUPT
BUSCLKX4
ADDRESS BUS
NOTE: Previous data can be operand data or the STOP opcode, depending on the last instruction.
shows the stop mode recovery time from interrupt or break
Read:
Write:
POR:
To minimize stop current, all pins configured as inputs should be driven to
a logic 1 or logic 0.
DATA BUS
CPUSTOP
R/W
POR
Bit 7
1
Figure 14-18. Stop Mode Recovery from Interrupt
Figure 14-19. SIM Reset Status Register (SRSR)
STOP ADDR
= Unimplemented
PIN
STOP +1
Figure 14-17. Stop Mode Entry Timing
6
0
PREVIOUS DATA
MC68HC908QB8 Data Sheet, Rev. 2
COP
5
0
STOP ADDR + 1
STOP + 2
ILOP
NOTE
STOP RECOVERY PERIOD
4
0
NEXT OPCODE
Figure 14-17
STOP + 2
ILAD
3
0
SAME
MODRST
shows stop mode entry timing and
SP
2
0
SAME
SP – 1
LVI
SAME
1
0
SAME
Freescale Semiconductor
SP – 2
Bit 0
0
0
SP – 3