DP8573AV National Semiconductor, DP8573AV Datasheet - Page 5

• 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

Connection Diagrams
Functional Description
The DP8573A contains a fast access real time clock inter-
rupt control logic and power fail detect logic All functions of
the RTC are controlled by a set of seven registers A simpli-
fied block diagram that shows the major functional blocks is
given in Figure 1
The blocks are described in the following sections
1 Real Time Clock
2 Oscillator Prescaler
3 Interrupt Logic
4 Power Failure Logic
5 Additional Supply Management
The memory map of the RTC is shown in the memory ad-
dressing table (Figure 2) A control bit in the Main Status
Register is used to select either control register block
INITIAL POWER-ON of BOTH V
V
the power fail circuitry to function correctly whenever power
is off the V
maximum of 1 M
trol registers will contain random data The user should en-
sure that the RTC is not in test mode (see register descrip-
tions)
REAL TIME CLOCK FUNCTIONAL DESCRIPTION
As shown in Figure 2 the clock has 8 bytes of counters
which count from 1 100 of a second to years Each counter
counts in BCD and is synchronously clocked The count se-
quence of the individual byte counters within the clock is
shown later in Table VII Note that the day of week day of
month and month counters all roll over to 1 The hours
counter in 12 hour mode rolls over to 1 and the AM PM bit
toggles when the hours rolls over to 12 (AM
The AM PM bit is bit D7 in the hours counter
All other counters roll over to 0 Upon initial application of
power the counters will contain random information
BB
and V
CC
CC
See NS Package Number N24C
may be applied in any sequence In order for
Order Number DP8573AN
pin must see a path to ground through a
The user should be aware that the con-
Dual-In-Line
Top View
BB
and V
CC
e
0 PM
TL F 9981 – 5
e
1)
5
FIGURE 2 DP8573A Internal Memory Map
See NS Package Number V28A
Order Number DP8573AV
Plastic Chip Carrier
Top View
TL F 9981 – 6
TL F 9981 – 7