Commercial and industrial ordering information, Ordering codes, Stk17t88 – Cypress AutoStore STK17T88 User Manual

Page 20: Register map detail

STK17T88

Document Number: 001-52040 Rev. *A

Page 20 of 22

Ordering Codes

0x7FF0

Flags

WDF

OSCF

CAL

WDF

Watchdog Timer Flag. This read-only bit is set to 1 when the watchdog timer is allowed to reach 0 without
being reset by the user. It is cleared to 0 when the Flags register is read or on power up

Alarm Flag. This read-only bit is set to 1 when the time and date match the values stored in the alarm
registers with the match bits = 0. It is cleared when the Flags register is read or on power up

Power-fail Flag. This read-only bit is set to 1 when power falls below the power-fail threshold V

SWITCH

. It

is cleared to 0 when the Flags register is read or on power up.

OSCF

Oscillator Fail Flag. Set to 1 on power up only if the oscillator is enabled and not running in the first 5ms
of operation. This indicates that the RTC backup power failed and the clock value is no longer valid. The
user must reset this bit to 0 to clear this condition.

CAL

Calibration Mode. When set to 1, a 512Hz square wave is output on the INT pin. When set to 0, the INT
pin resumes normal operation. This bit defaults to 0 (disabled) on power up.

Write Time. Setting the W bit to 1 freezes updates of the RTC registers. The user can then write to the
RTC registers, Alarm registers, Calibration register, Interrupt register and Flags register. Setting the W bit
to 0 disables writes to the registers and causes the contents of the real time clock registers to be transferred
to the timekeeping counters if the time has changed (a new base time is loaded). The bit defaults to 0 on
power up.

Read Time. Setting the R bit to 1 captures the current time in holding registers so that clock updates are
not during the reading process. Set the R bit to 0 to enable the holding register to resume clock updates.
The bit defaults to 0 on power up.

Register Map Detail

(continued)

Speed:
25 - 25 ns
45 - 45 ns

Package:
R = Plastic 48-pin 330 mil SSOP

Commercial and Industrial Ordering Information

STK17T88 - R F 45 I TR

Temperature Range:

C - Commercial (0 to 70°C)

Lead Finish

F = 100% Sn (Matte Tin) RoHS Compliant

I - Industrial (-40 to 85°C)

Packaging Option:
TR = Tape and Reel
Blank = Tube

Ordering Code

Description

Access Times (ns)

Temperature

STK17T88-RF25