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4.4.2 Low Voltage Reset (LVRSTIN)
This active-low input signal is used to initiate a system reset and to cause the backup
power supply source to be selected for the RAM array and the OSC/time-of-day timer.
This external reset signal resets the MMC2001 and most internal peripherals. The
debug module is unaffected by LVRSTIN; this function is provided through the TRST
pin.
4.4.3 Reset Out (RSTOUT)
This active-low output signal is used to reset external components. This pin is
asserted when any internal reset source is active.
4.5 Clock Signals
These signals are used by the MMC2001 for controlling or generating the system
clocks. See SECTION 8 CLOCK MODULE AND LOW-POWER MODES for more
information on the various clocking methods and frequencies.
4.5.1 Crystal Oscillator (XOSC, EXOSC)
These pins are the connections for an external crystal to the internal oscillator circuit
for generation of the internal LOW_REFCLK. EXOSC is the input pin, and XOSC is
the output.
4.5.2 Clock Input (CLKIN)
This input pin provides the HI_REFCLK clock source to the CPU and internal periph-
erals.
4.5.3 Clock Output (CLKOUT)
This output pin provides an external clock source, either the LO_REFCLK or the
HI_REFCLK.
4.6 Debug and Emulation Support Signals
These signals are used for testing or serial debugging. See SECTION 16 OnCE™
DEBUG MODULE for more information on these signals and debug mode.
4.6.1 Test Clock (TCK)
The test clock input (TCK) pin is the test clock used to synchronize the JTAG test
logic. The TCK pin has an internal 47-Kbyte pull-up resistor.
4.6.2 Test Data Input (TDI)
The test data input (TDI) pin is the serial input for test instructions and data. TDI is
sampled on the rising edge of TCK and it has an internal 47-Kbyte pull-up resistor.
MMC2001
REFERENCE MANUAL
Freescale Semiconductor, Inc.
SIGNAL DESCRIPTIONS
For More Information On This Product,
Go to: www.freescale.com
MOTOROLA
4-5
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