Demonstration Board for Freescale MCF5211, Rev. 1
Low-Power Modes
Freescale Semiconductor
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switch is released. An external pullup on the RSTI* line prevents spurious resets and allowing normal
operation.
8.2
Low-Voltage Detect
The MCF5211 utilizes an internal Low-Voltage Detect (LVD) to protect against under-voltage conditions.
The LVD is enabled out of RESET. Consult the MCF5213 Integrated Microcontroller Reference Manual
for details on configuring LVD operation.
8.3
Reset Indicator
The RESET LED turns on when the MCU is in RESET and remains on for the duration of a valid RSTO*
signal.
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Low-Power Modes
The MCF5211 supports several operational modes designed to reduce power consumption. Low-power
modes include Wait, Doze, Stop, and Halt. Refer to the MCF5213 Microcontroller Family Hardware
Specification and the MCF5213 Integrated Microcontroller Reference Manual for details on configuring
and using the various low-power modes.
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Timing
Timing for the M5211DEMO is provided by an on-chip, 8 MHz relaxation oscillator in default
configuration. Resistor R23 causes the MCU to select the internal oscillator as the timing source out of
reset. Refer to the M5213 Integrated Microcontroller Reference Manual for details on use and
configuration of internal timing.
Pad locations for an external crystal oscillator have been provided but not populated in default
configurations. The external oscillator is connected to the XTAL and EXTAL inputs. To implement an
external crystal oscillator simply remove R23, install the oscillator and related circuitry. The XTAL_EN
shunt must be installed to enable external timing operation.
Figure 8. OSC_EN Option Header
Pad locations for an optional 32.768 kHz have also been provided but not populated. The 32.768 kHz
timing input is connected to GPT0 and GPT1 inputs. To implement this timing input, simply install the
timing source and related circuitry.
Enables external crystal oscillator input to MCU
XTAL_EN
Disables external crystal oscillator input to MCU
ON
XTAL_EN
OFF