MC68HC08AZ16 Datasheet, PDF (93/527 Pages) Motorola, Inc – HCMOS Microcontroller Unit

System Integration Module (SIM)
; This code works if the H register has been pushed onto the stack in the break
; service routine software. This code should be executed at the end of the
; break service routine software.
HIBYTE EQU 5
LOBYTE EQU 6
;
If not SBSW, do RTI
BRCLR SBSW,SBSR, RETURN ; See if STOP or WAIT mode was exited by
; break.
TST LOBYTE,SP
; If RETURNLO is not ’0’,
BNE DOLO
; then just decrement low byte.
DEC HIBYTE,SP
; Else deal with high byte, too.
DOLO DEC LOBYTE,SP
; Point to STOP/WAIT opcode.
RETURN PULH
RTI
; Restore H register.
SIM reset status
register (SRSR)
This register contains six flags that show the source of the last reset. The
SIM reset status register can be cleared by reading it. A power-on reset
sets the POR bit and clears all other bits in the register.
Bit 7
6
5
4
3
2
1
Bit 0
SRSR ^{Read: POR}
PIN
COP
ILOP
ILAD
0
LVI
0
$FE01 _Write:
POR: 1
0
0
0
0
0
0
0
= Unimplemented
Figure 17. 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
MC68HC08AZ32
92
System Integration Module (SIM)
22-sim
MOTOROLA