Freescale Semiconductor MC68HC08KH12 - Manual (Page 83)

MC68HC(7)08KH12 — Rev. 1.1 Advance Information
Freescale Semiconductor 83
7.8 SIM Registers
The SIM has three memory mapped registers. Table 7-4 shows the
mapping of these registers.
7.8.1 Break Status Register (BSR)
The break status register contains a flag to indicate that a break caused
an exit from stop or wait mode.
SBSW — SIM Break Stop/Wait
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.
1 = Stop mode or wait mode was exited by break interrupt
0 = Stop mode or wait mode was not exited by break
interrupt
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.
Table 7-4. SIM Registers
Address Register Access Mode
$FE00 BSR User
$FE01 RSR User
$FE03 BFCR User
Address: $FE00
Bit 7 6 5 4 3 2 1 Bit 0
Read:
R R R R R R
SBSW
R
Write: Note 1
Reset: 0
R = Reserved 1. Writing a logic zero clears SBSW
Figure 7-20. Break Status Register (BSR)