Electronic Components Datasheet Search
  English  ▼

Delete All
ON OFF
ALLDATASHEET.COM

X  

Preview PDF Download HTML

X1243 Datasheet(PDF) 2 Page - Intersil Corporation

Part No. X1243
Description  Real Time Clock/Calendar/Alarm with EEPROM
Download  17 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Maker  INTERSIL [Intersil Corporation]
Homepage  http://www.intersil.com/cda/home
Logo 

X1243 Datasheet(HTML) 2 Page - Intersil Corporation

 
Zoom Inzoom in Zoom Outzoom out
 2 / 17 page
background image
2
FN8249.0
April 28, 2005
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 collector 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 inter-face speeds.
VBACK
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.
Interrupt Output—IRQ
This is an interrupt signal output. This signal noties a host
processor that alarm has occurred and requests action. It is
an open drain active LOW output.
X1, X2
The X1 and X2 pins are the input and output, respectively, of
an inverting amplier that can be con-gured for use as an on-
chip oscillator. A 32.768kHz quartz crystal is used.
Recommended crystal is a Citizen CFS-206. 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.
Power Control Operation
The Power control circuit accepts a V
CC and a VBACK input.
The power control circuit will switch to V
BACK when VCC <
V
BACK – 0.2V. It will switch back to VCC when VCC exceeds
V
BACK.
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 X1243 powers up after the loss of
both V
CC and VBACK, the clock will not increment until at
least one byte is written to the clock register.
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 nite 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 the clock on the ACK bit prior
to RTC data output) into a separate latch to avoid time
changes during the read operation. The clock continues to
run. Alarms occurring during a read are unaffected by the
read operation.
X1243
X1
X2
VBack
VCC
IRQ
SCL
SDA
VSS
1
2
3
4
7
8
6
5
8-Pin TSSOP
X1243
X1
X2
VBack
VCC
IRQ
SCL
SDA
VSS
1
2
3
4
7
8
6
5
8-Pin SOIC
X1
X2
68pF
12pF
360K
10M
FIGURE 1. RECOMMENDED CRYSTAL CONNECTION
VBACK
VCC = VBACK -0.2V
Internal
Voltage
VCC
FIGURE 2. POWER CONTROL
X1243


Html Pages

1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17 


Datasheet Download




Link URL




Privacy Policy
ALLDATASHEET.COM
Does ALLDATASHEET help your business so far?  [ DONATE ]  

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Alldatasheet API   |   Link Exchange   |   Manufacturer List
All Rights Reserved© Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn