Phytec phyCORE-MCF548x, Hardware Manual

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Real-Time Clock
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PHYTEC Messtechnik GmbH 2005 L-645e_1
55
9 Real-Time Clock RTC-8564 (U16)
For real-time or time-driven applications, the phyCORE-MCF548x is
equipped with a RTC-8564 Real-Time Clock at U16. This RTC device
provides the following features:
•
Serial input/output bus (I
2
C), address 0xA2
•
Power consumption
Bus active (400 kHz): < 1 mA
Bus inactive, CLKOUT inactive: < 1
µ
A
•
Clock function with four year calendar
•
Century bit for year 2000-compliance
•
Universal timer with alarm and overflow indication
•
24-hour format
•
Automatic word address incrementing
•
Programmable alarm, timer and interrupt functions
If the phyCORE-MCF548x is equipped with a battery (VBAT), the
Real-Time Clock runs independently of the board’s power supply.
The Real-Time Clock is programmed via the I
2
C bus (address 0xA2 /
0xA3). Since the MCF548X is equipped with an internal I
2
C
controller, the I
2
C protocol is processed very effective without
extensive processor action (refer also to section 6.3)
The Real-Time Clock also provides an interrupt output that extends to
the /WAKEUP signal via jumper J26. An interrupt occurs in the event
of a clock alarm, timer alarm, timer overflow and event counter alarm.
It has to be cleared by software. With the interrupt function, the Real-
Time Clock can be utilized in various applications.
If the RTC interrupt should be used as a software interrupt via a
corresponding interrupt input of the processor, the signal /IRTC must
be connected externally with a processor interrupt input.