Freescale Semiconductor MC68HC908MR32 Manual Do Utilizador
Break Module (BRK)
MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1
Freescale Semiconductor
253
18.2.1.2 CPU During Break Interrupts
The CPU starts a break interrupt by:
•
Loading the instruction register with the SWI instruction
•
Loading the program counter with $FFFC and $FFFD ($FEFC and $FEFD in monitor mode)
The break interrupt begins after completion of the CPU instruction in progress. If the break address
register match occurs on the last cycle of a CPU instruction, the break interrupt begins immediately.
register match occurs on the last cycle of a CPU instruction, the break interrupt begins immediately.
18.2.1.3 TIM1 and TIM2 During Break Interrupts
A break interrupt stops the timer counters.
18.2.1.4 COP During Break Interrupts
The COP is disabled during a break interrupt when V
TST
is present on the RST pin.
18.2.2 Low-Power Modes
The WAIT and STOP instructions put the MCU in low power- consumption standby modes.
18.2.2.1 Wait Mode
If enabled, the break module is active in wait mode. In the break routine, the user can subtract one from
the return address on the stack if SBSW is set. Clear the BW bit by writing logic 0 to it.
the return address on the stack if SBSW is set. Clear the BW bit by writing logic 0 to it.
18.2.2.2 Stop Mode
The break module is inactive in stop mode. The STOP instruction does not affect break module register
states.
states.
18.2.3 Break Module Registers
These registers control and monitor operation of the break module:
•
Break status and control register (BRKSCR)
•
Break address register high (BRKH)
•
Break address register low (BRKL)
•
SIM break status register (SBSR)
•
SIM break flag control register (SBFCR)