UPD4991ACX Renesas Electronics America, UPD4991ACX Datasheet - Page 9

• Manufacturer Part Number: UPD4991ACX
• Manufacturer: Renesas Electronics America

Specifications of UPD4991ACX

• Lead Free Status / RoHS Status: Supplier Unconfirmed

and has 1 channel for an alarm function.
counter can be used in two modes: 12-hour and 24-hour modes. Month, date, day of week, minute, and second can
be specified for the alarm function.
commercially available dry cells, mercury cells, lithium batteries, Ni-Cd batteries, and super capacitors (electric
double-layer capacitors) can be used as back-up batteries.
FAXes, ECRs, and POSs.
1.1 Features
The PD4991A is an IC for inputting/outputting 4-bit parallel time data and calendar data in a microcontroller system
This IC has seven types of internal counters: year, month, date, day of week, hour, minute, and second. The hour
Because the operating voltage range of this IC is very wide, from 2.0 to 5.5 V (4.5 to 5.5 V when the IC is accessed),
The PD4991A is suitable for systems requiring a watch function, such as personal computers, word processors,
• Time (hour, minute, and second) and calendar (leap year, year, month, date, and day of week) counters
• Alarm function (month, date, day of week, hour, minute, and second)
• Seven alarm coincidence signals and five interval timers
• Automatic identification and user-setting of leap year (up to 2099)
• 12- and 24-hour modes selectable
• High speed response (cycle time: 150 ns)
• Low current consumption (2 A Typ. at back up)
• Address bus: 4 bits, data bus: 4 bits
• Upward-compatible with PD4991 in function and characteristics (For details, refer to Appendix 3.)
Basic Specifications
• Reference frequency (crystal oscillation) ........ 32.768 kHz
• Data format ....................................................... BCD
• Data function
• Data input/output (D
• Mode selection
• Timing pulse output (TP1, TP2)
• Chip select (CS
Year, month, date, day of week, hour, minute, and second counters
Leap year is automatically identified or can be set by the user.
Years are set in 2-digit units.
Hours can be indicated in 12- or 24-hour mode.
4-bit parallel input/output
Data is input/output by enabling writing with the WE signal and enabling reading with the OE signal.
The mode is selected by setting the address to 0F
TP1 ... Alarm coincidence signal output
TP2 ... Interval timer signal output
All input signals except X
All input signals are selected when CS
2048, 1024, 64, 16, 1 Hz, or 1-pulse output (H
60, 30, 10, 1, or 0.1 s selectable
1
, CS
3
2
, D
)
2
, D
IN
are disabled when CS
1
, D
CHAPTER 1 OUTLINE OF PD4991A
0
)
1
= “L” and CS
1
H
= “H” and CS
and writing data.
L) selectable
2
= “H”.
2
= “L”.
7