MC68HC908JK3 MOTOROLA [Motorola, Inc], MC68HC908JK3 Datasheet - Page 92

• Manufacturer Part Number: MC68HC908JK3
• Description: MC68HC908JK1
• Manufacturer: MOTOROLA [Motorola, Inc]

System Integration Module (SIM)
7.8.2 Reset Status Register (RSR)
Technical Data
92
;
;
;
;
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
LOBYTE
DOLO
RETURN
EQU
EQU
If not SBSW, do RTI
BRCLR
TST
BNE
DEC
DEC
PULH
RTI
SBSW — SIM Break Stop/Wait
SBSW can be read within the break state SWI routine. The user can
modify the return address on the stack by subtracting one from it. The
following code is an example of this. Writing zero to the SBSW bit clears
it.
This register contains six flags that show the source of the last reset.
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.
This status bit is useful in applications requiring a return to wait or stop
mode after exiting from a break interrupt. Clear SBSW by writing a
logic zero to it. Reset clears SBSW.
5
6
SBSW,BSR, RETURN
LOBYTE,SP
DOLO
HIBYTE,SP
LOBYTE,SP
1 = Stop mode or wait mode was exited by break interrupt
0 = Stop mode or wait mode was not exited by break interrupt
System Integration Module (SIM)
;
;
; If RETURNLO is not zero,
; then just decrement low byte.
; Else deal with high byte, too.
; Point to WAIT/STOP opcode.
; Restore H register.
See if wait mode or stop mode was exited
by break.
MC68H(R)C908JL3
MOTOROLA
—
Rev. 1.0