M440T1MV datasheet(4/26 Pages) STMICROELECTRONICS

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M440T1MV

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SUMMARY DESCRIPTION

The M440T1MV TIMEKEEPER® RAM is a 16Mbit,

non-volatile static RAM organized as 1,024K by 32

bits and real time clock organized as 64 bytes by

8 bits. The special PBGA package provides a fully

integrated battery back-up memory and real time

clock solution. In the event of power instability or

absence, a self-contained battery maintains the

timekeeping operation and provides power for a

CMOS static RAM. Control circuitry monitors VCC

and invokes write protection to prevent data cor-

ruption in the memory and RTC.

The clock keeps track of tenths/hundredths of sec-

onds, seconds, minutes, hours, day, date, month,

and year information. The last day of the month is

automatically adjusted for months with less than

31 days, including leap year correction.

The clock operates in one of two formats:

–

a 12-hour mode with an AM/PM indicator; or

–

a 24-hour mode

The M440T1MV is in a 168-ball PBGA module that

integrates the RTC, the battery, and SRAM in one

package.

Figure 2. Logic Diagram

Table 1. Signal Names

AI04200

VCC

M440T1MV

VSS

IRQ

RSV2

RSV1

A0 – A19

DQ0 – DQ31

DQC0 – DQC7

W1 – W4

E1 – E4

A0 - A19

Address Inputs

DQ0 - DQ31

NVRAM Data Input/Output

DQC0 - DQC7

Clock Data Input/Output

E1 - E4

NVRAM Chip Enable Inputs

Clock Chip Enable Input

W1 - W4

NVRAM WRITE Enable Inputs

Clock WRITE Enable Input

Output Enable Input

Clock Output Enable Input

Battery Low Output (Open

Drain)

IRQ

Interrupt Output (Open Drain)

RSV1

Reserved

RSV2

Reserved

No Connect

VCC

Supply Voltage

VSS

Ground

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