MC68HC908AP16CFA MOTOROLA [Motorola, Inc], MC68HC908AP16CFA Datasheet - Page 149

• Manufacturer Part Number: MC68HC908AP16CFA
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

9.7.1 SIM Break Status Register
MC68HC908AP Family — Rev. 2.5
MOTOROLA
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
5
6
SBSW,SBSR, RETURN
LOBYTE,SP
DOLO
HIBYTE,SP
LOBYTE,SP
Note: Writing a logic 0 clears SBSW.
Address:
The SIM break status register (SBSR) contains a flag to indicate that a
break caused an exit from stop mode or wait mode.
SBSW — Break Wait Bit
SBSW can be read within the break interrupt routine. The user can
modify the return address on the stack by subtracting 1 from it. The
following code is an example.
Reset:
Read:
Write:
This status bit is set when a break interrupt causes an exit from wait
mode or stop mode. Clear SBSW by writing a logic 0 to it. Reset clears
SBSW.
Freescale Semiconductor, Inc.
For More Information On This Product,
1 = Stop mode or wait mode was exited by break interrupt
0 = Stop mode or wait mode was not exited by break interrupt
$FE00
Bit 7
R
Figure 9-20. SIM Break Status Register (SBSR)
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R
6
;
;
;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.
R
R
5
= Reserved
R
4
R
3
System Integration Module (SIM)
R
2
SBSW
Note
1
0
SIM Registers
Data Sheet
Bit 0
R
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