MC9S08LC60 Datasheet, PDF (70/358 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 5 Resets, Interrupts, and System Configuration
The SRTISC register includes a read-only status flag, a write-only acknowledge bit, and a 3-bit control
value (RTIS) used to select one of seven wakeup periods. The RTI has a local interrupt enable, RTIE, to
allow masking of the real-time interrupt. The RTI can be disabled by writing each bit of RTIS to zeroes,
and no interrupts will be generated. See Section 5.8.7, “System Real-Time Interrupt Status and Control
Register (SRTISC)” for detailed information about this register.
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 the direct-page register summary in Chapter 4, “Memory” of this data sheet for the absolute
address assignments for all registers. This section refers to registers and control bits only by their names.
A Freescale-provided equate or header file is used to translate these names into the appropriate absolute
addresses.
Some control bits in the SOPT1, SOPT2, 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)
These bits are used to configure the IRQ function, report status, and acknowledge IRQ events.
R
W
Reset
7
6
5
4
3
2
1
0
IRQF
0
IRQPDD IRQEDG
IRQPE
IRQIE
IRQACK
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 5-2. Interrupt Request Status and Control Register (IRQSC)
0
IRQMOD
0
Table 5-3. IRQSC Field Descriptions
Field
Description
6
IRQPDD
5
IRQEDG
Interrupt Request (IRQ) Pull Device Disable— This read/write control bit is used to disable the internal
pullup/pulldown device when the IRQ pin is enabled (IRQPE = 1) allowing for an external device to be used.
0 IRQ pull device enabled if IRQPE = 1.
1 IRQ pull device disabled if IRQPE = 1.
Interrupt Request (IRQ) Edge Select — This read/write control bit is used to select the polarity of edges or
levels on the IRQ pin that cause IRQF to be set. The IRQMOD control bit determines whether the IRQ pin is
sensitive to both edges and levels or only edges. When the IRQ pin is enabled as the IRQ input and is configured
to detect rising edges, the optional pullup resistor is re-configured as an optional pulldown resistor.
0 IRQ is falling edge or falling edge/low-level sensitive.
1 IRQ is rising edge or rising edge/high-level sensitive.
MC9S08LC60 Series Advance Information Data Sheet, Rev. 2
70
PRELIMINARY
Freescale Semiconductor