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參數(shù)資料
| 型號： | X1240 |
| 英文描述： | Real Time Clock/Calendar with EEPROM |
| 中文描述： | 實時時鐘/日歷帶有EEPROM |
| 文件頁數(shù)： | 2/19頁 |
| 文件大小： | 74K |
| 代理商： | X1240 |
X1240
2
PIN CONFIGURATION
PIN DESCRIPTIONS
Serial Clock (SCL)
The SCL input is used to clock all data into and out of
the device. The input buffer on this pin is always active
(not gated).
Serial Data (SDA)
SDA is a bidirectional pin used to transfer data into
and out of the device. It has an open drain output and
may be wire ORed with other open drain or open col-
lector outputs. The input buffer is always active (not
gated).
An open drain output requires the use of a pull-up
resistor. The output circuitry controls the fall time of
the output signal with the use of a slope controlled
pull-down. The circuit is designed for 400kHz 2-wire
interface speeds.
V
BACK
This input provides a backup supply voltage to the
device. V
BACK
supplies power to the device in the
event the V
CC
supply fails.
X1, X2
The X1 and X2 pins are the input and output, respec-
tively, of an inverting amplifier that can be configured
for use as an on-chip oscillator. A 32.768kHz quartz
crystal is used. Recommeded crystals are Sieko VT-200
or Epson C-002RX. The crystal supplies a timebase
for a clock/oscillator. The internal clock can be driven
by an external signal on X1, with X2 left unconnected.
Figure 1. Recommended Crystal connection
POWER CONTROL OPERATION
The Power control circuit accepts a V
input. The power control circuit will switch to V
when V
CC
< V
BACK
- 0.2V. It will switch back to V
when V
CC
exceeds V
BACK
CC
and a V
BACK
BACK
CC
.
Figure 2. Power Control
REAL TIME CLOCK OPERATION
The Real Time Clock (RTC) uses an external, 32.768KHz
quartz crystal to maintain an accurate internal repre-
sentation of the year, month, day, date, hour, minute,
and seconds. The RTC has leap-year correction and a
century byte. The clock will also correct for months hav-
ing fewer than 31 days and will have a bit that controls
24 hour or AM/PM format. When the X1240 powers up
after the loss of both V
CC
and V
increment until at least one byte is written to the clock
register.
BACK
, the clock will not
Reading the Real Time Clock
The RTC is read by initiating a Read command and
specifying the address corresponding to the register of
the Real Time Clock. The RTC Registers can then be
read in a Sequential Read Mode. Since the clock runs
continuously and a read takes a finite amount of time,
there is the possibility that the clock could change dur-
ing the course of a read operation. In this device, the
time is latched by the read command (falling edge of
X1240
X1
X2
V
Back
V
CC
NC
SCL
SDA
V
SS
1
2
3
4
7
6
5
8
8 pin TSSOP
X1240
X1
X2
NC
V
SS
V
Back
SCL
SDA
V
CC
1
2
3
4
7
6
5
8
8 pin SOIC
X1
X2
43pF
18pF
220K
10M
V
BACK
V
CC
= V
BACK
-0.2V
Internal
Voltage
V
CC
相關PDF資料 |
PDF描述 |
|---|---|
| X1240S8 | Real Time Clock/Calendar with EEPROM |
| X1240S8I | Real Time Clock/Calendar with EEPROM |
| X1240V8 | Real Time Clock/Calendar with EEPROM |
| X1240V8I | Real Time Clock/Calendar with EEPROM |
| X1243 | Real Time Clock/Calendar/Alarm with EEPROM |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| X1240S8 | 制造商:XICOR 制造商全稱:Xicor Inc. 功能描述:Real Time Clock/Calendar with EEPROM |
| X1240S8I | 制造商:XICOR 制造商全稱:Xicor Inc. 功能描述:Real Time Clock/Calendar with EEPROM |
| X1240V8 | 制造商:Intersil Corporation 功能描述:Real Time Clock, Non-Volatile, 8 Pin, Plastic, TSSOP |
| X1240V8I | 制造商:XICOR 制造商全稱:Xicor Inc. 功能描述:Real Time Clock/Calendar with EEPROM |
| X1241V8I-2.7A | 制造商:Intersil Corporation 功能描述:REAL TIME CLOCK SERL 2KBYTE 8TSSOP N - Rail/Tube |
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