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參數(shù)資料
| 型號： | PCF8573P |
| 廠商： | NXP SEMICONDUCTORS |
| 元件分類： | XO, clock |
| 英文描述： | Clock/calendar with Power Fail Detector |
| 中文描述： | 0 TIMER(S), REAL TIME CLOCK, PDIP16 |
| 封裝： | 0.300 INCH, PLASTIC, SOT-38-4, DIP-16 |
| 文件頁數(shù)： | 5/24頁 |
| 文件大?。?/td> | 198K |
| 代理商： | PCF8573P |
1997 Mar 28
5
Philips Semiconductors
Product specification
Clock/calendar with Power Fail Detector
PCF8573
7
FUNCTIONAL DESCRIPTION
7.1
Oscillator
The PCF8573 has an integrated crystal-controlled
oscillator which provides the timebase for the prescaler.
The frequency is determined by a single 32.76 kHz crystal
connected between OSCI and OSCO. A trimmer is
connected between OSCI and V
DD
.
7.2
Prescaler and time counter
The prescaler provides a 128 Hz signal at the FSET output
for fine adjustment of the crystal oscillator without loading
it. The prescaler also generates a pulse once a second to
advance the seconds counter. The carry of the prescaler
and the seconds counter are available at the outputs SEC,
MIN respectively, and are also readable via the I
2
C-bus.
The mark-to-space ratio of both signals is 1 : 1. The time
counter is advanced one count by the falling edge of output
signal MIN. A transition from HIGH-to-LOW of output
signal SEC triggers MIN to change state. The time counter
counts minutes, hours, days and months, and provides a
full calendar function which needs to be corrected only
once every four years - to allow for leap-year. Cycle
lengths are shown in Table 1.
7.3
Alarm register
The alarm register is a 24-bit memory. It stores the
time-point for the next setting of the status flag COMP.
Details of writing and reading of the alarm register are
included in the description of the characteristics of the
I
2
C-bus.
7.4
Comparator
The comparator compares the contents of the alarm
register and the time counter, each with a length of 24 bits.
When these contents are equal the flag COMP will be set
4 ms after the falling edge of MIN. This set condition
occurs once at the beginning of each minute. This
information is latched, but can be cleared by an instruction
via the I
2
C-bus. A clear instruction may be transmitted
immediately after the flag is set and will be executed. Flag
COMP information is also available at the output COMP.
The comparison may be based upon hours and minutes
only if the internal flag NODA (no date) is set. Flag NODA
can be set and cleared by separate instructions via the
I
2
C-bus, but it is undefined until the first set or clear
instruction has been received. Both COMP and NODA
flags are readable via the I
2
C-bus.
Table 1
Cycle length of the time counter
Note
1.
During February of a leap-year the ‘Time Counter Days’ may be set to 29 by directly writing into it using the ‘execute
address’ function. Leap-years must be tracked by the system software.
UNIT
NUMBER OF BITS
COUNTING CYCLE
CARRY FOR
FOLLOWING UNIT
59
→
00
23
→
00
28
→
01
or 29
→
01
30
→
01
31
→
01
12
→
01
CONTENT OF MONTH
COUNTER
minutes
hours
days
(1)
7
6
6
00 to 59
00 to 23
01 to 28
2 (note 1)
2 (note 1)
4, 6, 9, 11
1, 3, 5, 7, 8, 10, 12
01 to 30
01 to 31
01 to 12
months
5
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| PCF8573T | Clock/calendar with Power Fail Detector |
| PCF8574 | Remote 8-bit I/O expander for I2C-bus |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| PCF8573PN | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Real-Time Clock |
| PCF8573T | 制造商: 功能描述: 制造商:undefined 功能描述: 制造商:NXP Semiconductors 功能描述:Real Time Clock, 16 Pin, Plastic, SOP |
| PCF8573TD | 制造商:NXP Semiconductors 功能描述:Real Time Clock, 16 Pin, Plastic, SOP |
| PCF8573TD-T | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Real-Time Clock |
| PCF8574 | 制造商:TI 制造商全稱:Texas Instruments 功能描述:REMOTE 8-BIT I/O EXPANDER FOR I2C BUS |
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