NXP Semiconductors MC9S08QL4, Reference Manual

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Chapter 5 Resets, Interrupts, and General System Control
MC9S08QL8 MCU Series Reference Manual, Rev. 1
64 NXP Semiconductors
peripheral with a gated clock cannot be used unless its clock is enabled. Writing to the registers of a
peripheral with a disabled clock has no effect.
NOTE
User software must disable the peripheral before disabling the clocks to the
peripheral. When clocks are re-enabled to a peripheral, the peripheral
registers need to be re-initialized by user software.
In stop modes, the bus clock is disabled for all gated peripherals, regardless of the settings in SCGC1 and
SCGC2.
5.8 Reset, Interrupt, and System Control Registers and Control Bits
One 8-bit register in the direct page register space and eight 8-bit registers in the high-page register space
are related to reset and interrupt systems.
Refer to Table 4-2 and Table 4-3 in Chapter 4, Memory for the absolute address assignments for all
registers. This section refers to registers and control bits only by their names. An NXP-provided equate or
header file is used to translate these names into the appropriate absolute addresses.
Some control bits in the SOPT1 and SPMSC2 registers are related to modes of operation. Although brief
descriptions of these bits are provided here, the related functions are discussed in greater detail in
Chapter 3, Modes of Operation .
5.8.1 Interrupt Pin Request Status and Control Register (IRQSC)
This direct-page register includes status and control bits which are used to configure the IRQ function,
report status, and acknowledge IRQ events.
7 6 5 4 3 2 1 0
R 0
IRQPDD IRQEDG IRQPE
IRQF 0
IRQIE IRQMOD
W IRQACK
Reset 0 0 0 0 0 0 0 0
= Unimplemented or Reserved
Figure 5-2. Interrupt Request Status and Control Register (IRQSC)