PT7C43390 Datasheet, PDF (17/38 Pages) Pericom Semiconductor Corporation – Real-time Clock Module

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PT7C43390/43390C
Real-time Clock Module
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8. Nonexistent Data and End-of-Month
When users write the real-time data, the RTC checks it. In case that the data is invalid, the RTC does the following procedures.
 Processing of nonexistent data
*1. In 12-hour mode, write the AM / PM flag (B1 in hour data in the real-time data register). In 24-hour expression, the AM / PM
flag in the real-time data register is omitted. However in the flag of reading, users are able to read 0; 0 to 11, 1; 12 to 23.
*2. Processing of nonexistent data, regarding second data, is done by a carry pulse which is generated in 1 second, after writing.
At this point the carry pulse is sent to the minute-counter.
 Correction of end-of-month
A nonexistent day, such as February 30 and April 31, is set to the first day of the next month.
9.Alarm and Interrupt Output
9.1. INT1 Pin and INT2 Pin Output Mode
These are selectable for the output mode for INT1 and INT2 pins; Alarm interrupt, the output of user-set frequency, per-minute
edge interrupt output, minute-periodical interrupt output 1. In the INT1 pin output mode, in addition to the above modes, minute-
periodical interrupt output 2 and 32.768 kHz Output are also selectable. To switch the output mode, use the status register 2. Refer
to "Status register 2" in "Configuration of Registers". When switching the output mode, be careful of the output status of the pin.
Especially, when using alarm interrupt / output of frequency, switch the output mode after setting "00h" in the INT1 / INT2
register. In 32.768 kHz output / per-minute edge interrupt output / minute-periodical interrupt output, it is unnecessary to set data
in the INT1 / INT2 register for users. Refer to the followings regarding each operation of output modes.
a. Alarm Interrupt Output
Alarm interrupt output is the function to output "L" from the INT1 / INT2 pin, at the alarm time which is set by user has come. If
setting the pin output to "H", turn off the alarm function by setting "0" in INT1AE / INT2AE in the status register 2. To set the
alarm time, set the data of day of the week, hour and minute in the INT1 / INT2 register. Refer to "INT1 register and INT2
register" in "Configuration of Registers".
2015-12-0001
PT0280-8 12/11/15
17