DP8573AV National Semiconductor, DP8573AV Datasheet - Page 14

• Manufacturer Part Number: DP8573AV
• Description: Clock IC
• Manufacturer: National Semiconductor

Specifications of DP8573AV

• Date Format: BCD
• Clock Format: 12 Or 24 Hr
• Clock Ic Type: RTC
• Digital Ic Case Style: LCC
• No. Of Pins: 28
• Peak Reflow Compatible (260 C): No
• Supply Voltage Max: 5.5V
• Leaded Process Compatible: No
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Application Hints
5
6
Typical Application
Test bit D6 in the Periodic Flag Register
IF a 1 go to 4 1 If this bit remains a 1 after 3 seconds
then abort and check hardware The crystal may be de-
fective or not installed There may be a short at OSC IN
or OSC OUT to V
is less than 10 M
IF a 0 then the oscillator is running go to step 7
Write a 0 to bit D6 in the Periodic Flag Register This
action puts the clock chip in the battery backed mode
This mode can be entered only if the OSC fail flag (bit
D6 of the Periodic Flag Register) is a 0 Reminder bit D6
is a dual function bit When read D6 returns oscillator
status When written D6 causes either the Battery
Backed Mode or the Single Supply Mode of operation
CC
or GND or to some impedance that
(Continued)
These components may be necessary to meet UL requirements
for lithium batteries Consult battery manufacturer
14
7
8
9
The only method to ensure the chip is in the battery
backed mode is to measure the waveform at the OSC
OUT pin If the battery backed mode was selected suc-
cessfully then the peak to peak waveform at OSC OUT
is referenced to the battery voltage If not in battery
backed mode the waveform is referenced to V
measurement should be made with a high impedance
low capacitance probe (10 M
probe or better) Typical peak to peak swings are within
0 6V of V
Write a 1 to bit D7 of Interrupt Control Register 1 This
action enables the PFAIL pin and associated circuitry
Write a 1 to bit D4 of the Real Time Mode Register This
action ensures that bit D7 of Interrupt Control Register 1
remains a 1 when V
Initialize the rest of the chip as needed
CC
and ground respectively
BB l
V
CC
(Standby Mode)
10 pF oscilloscope
TL F 9981– 19
CC
The