MC68HC08AZ32A Datasheet, PDF (276/312 Pages) Motorola, Inc – HCMOS Microcontroller Unit

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19.2.1.1 Flag Protection During Break Interrupts
The system integration module (SIM) controls whether or not module status bits can be cleared during
the break state. The BCFE bit in the SIM break flag control register (SBFCR) enables software to clear
status bits during the break state. See Chapter 15 System Integration Module (SIM), and the Break
Interrupts subsection for each module.
19.2.1.2 TIM and PIT During Break Interrupts
A break interrupt stops the timer counter.
19.2.1.3 COP During Break Interrupts
The COP is disabled during a break interrupt when V_TST is present on the RST pin. For V_TST see 20.5 5.0
Volt DC Electrical Characteristics.
19.2.2 Break Module Registers
Three 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)
19.2.2.1 Break Status and Control Register (BRKSCR)
The break status and control register contains break module enable and status bits.
Address: $FE0E
Bit 7
6
5
4
3
2
1
Bit 0
Read:
0
0
0
0
0
0
BRKE BRKA
Write:
R
R
R
R
R
R
Reset: 0
0
0
0
0
0
0
0
R
= Reserved
Figure 19-4. Break Status and Control Register (BRKSCR)
BRKE — Break Enable Bit
This read/write bit enables breaks on break address register matches. Clear BRKE by writing a 0 to
bit 7. Reset clears the BRKE bit.
1 = Breaks enabled on 16-bit address match
0 = Breaks disabled on 16-bit address match
BRKA — Break Active Bit
This read/write status and control bit is set when a break address match occurs. Writing a 1 to BRKA
generates a break interrupt. Clear BRKA by writing a 0 to it before exiting the break routine. Reset
clears the BRKA bit.
1 = Break address match
0 = No break address match
19.2.2.2 Break Address Registers (BRKH and BRKL)
The break address registers contain the high and low bytes of the desired breakpoint address. Reset
clears the break address registers.
MC68HC08AZ32A Data Sheet, Rev. 2
276
Freescale Semiconductor