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CKOE — CLKOUT Enable
This bit controls the drive enable for the CLKOUT pin. It is cleared by POR, a qualified
assertion of the RSTIN pin, or a qualified assertion of the LVRSTIN pin.
0 = CLKOUT is disabled and forced to the low state
1 = CLKOUT is enabled and driven from the source selected by CKOS
LVRSTIN — LVRSTIN Pin
This bit is set when the LVRSTIN pin is asserted to reset the MMC2001 chip. It is not
affected by the other reset sources. When the POR bit is set, however, this bit is
undefined. This bit is cleared by writing to RSCR.
RST — RSTIN Pin
This bit is set when the RSTIN pin is asserted and qualified by the four-cycle qualifier
to reset the MMC2001 chip. It is not affected by the other reset sources. When the
POR bit is set, however, this bit is undefined. It is cleared by writing to RSCR.
POR — Power-On Reset
This bit is set when an internal POR occurs to reset the chip. It is not affected by the
other reset sources. It is cleared by writing to RSCR.
WDR — Watchdog Reset
This bit is set when the watchdog timer expires. It is cleared by POR, a qualified
assertion of the RSTIN pin, a qualified assertion of the LVRSTIN pin, or by writing to
RSCR.
9.4 Time-of-Day Timer
The time-of-day timer (TOD) is a free-running timer that is clocked by the crystal oscil-
lator at a frequency of 256 Hz (LOW_REFCLK/128). It is comprised of a 32-bit regis-
ter which counts seconds, and another 32-bit register which holds an 8-bit fraction of
a second, where bit 31 is 1/2 of a second and bit 24 is 1/256 of a second.
The TOD has an alarm function which compares the seconds and fraction registers
with the seconds alarm and fraction alarm register and issues an interrupt if there is a
match.
24
TOD Fraction Alarm
24
TOD Fraction
256 Hz
24
TOD Fraction Latch
MOTOROLA
9-4
Freescale Semiconductor, Inc.
31
0
31
0
31
MMC2001 Internal Bus
Figure 9-3 TOD Block Diagram
TIMER/RESET MODULE
For More Information On This Product,
Go to: www.freescale.com
32-Bit TOD Seconds Alarm
32-Bit TOD Seconds
Alarm
31
Interrupt
31
MMC2001
REFERENCE MANUAL
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