RX − 8801 SA / JE

3) AIE ( Alarm Interrupt Enable ) bit

When an alarm timer interrupt event occurs (when the AF bit value changes from "0" to "1"), this bit's value specifies if an interrupt signal is generated (/INT status changes from Hi-Z to low) or is not generated (/INT status remains Hi-Z).

When a "1" is written to this bit, an interrupt signal is generated (/INT status changes from Hi-Z to low) when an interrupt event is generated.

When a "0" is written to this bit, no interrupt signal is generated when an interrupt event occurs.

AIE

Data

Function

 

0

When an alarm interrupt event occurs, an interrupt signal is not generated

 

or is canceled (/INT status changes from low to Hi-Z).

 

 

 

 

 

Write/Read

 

When an alarm interrupt event occurs, an interrupt signal is generated (/INT

 

status changes from Hi-Z to low).

 

1

 

∗ When an alarm interrupt event has been generated low-level output from the /INT pin occurs

 

 

only when the value of the control register's AIE bit is "1". This setting is retained until the AF

 

 

bit value is cleared to zero. (No automatic cancellation)

 

 

 

∗For details, see "8.5. Alarm Interrupt Function".

[Caution]

(1)The /INT pin is a shared interrupt output pin for three types of interrupts. It outputs the OR'ed result of these interrupt outputs.

When an interrupt has occurred (when the /INT pin is at low level), the UF, TF, read AF flags to determine which flag has a value of "1" (this indicates which type of interrupt event has occurred).

(2)To keep the /INT pin from changing to low level, write "0" to the UIE, TIE, and AIE bits. To check whether an event has occurred without outputting any interrupts via the /INT pin, use software to monitor the value of the UF, TF, and AF interrupt flags.

4)RESET bit

It also resets the RTC module's internal counter value when the value is less than one second.

Writing a "1" to this bit stops the counter operation and resets the RTC module's internal counter value when the value is less than one second.

If a STOP-condition or repeated START-condition(I2C) is received while the 0.95-second bus timeout function is operating, stop status is automatically canceled (the RESET bit value is changed from "1" to "0").

∗For optimum performance, do not use this bit for functions other than the clock and calendar functions.

RESET

Data

Description

 

 

[Normal operation mode]

 

 

This bit is used to cancel stop status for (i.e., restart) the clock and calendar

 

0

function. Also, when "1" is written to the RESET bit, it cancels stop status for

 

 

the fixed-cycle timer function.

 

 

∗ Since operation is not restarted when the STOP bit value is "1", to restart operation, a "0" must

 

 

be written to both the STOP bit and the RESET bit.

 

 

[Operation stop mode]

 

 

Stops updating of year, month, date, day, hour, minute, and second values

 

 

and partially stops the fixed-cycle timer function.

Write/Read

 

(Stop 1) Stops updating of year, month, date, day, hour, minute, and

 

second values

 

 

• This stops all clock and calendar update operations.

 

 

Once this occurs, no more time update interrupt events or alarm

 

1

interrupt events occur.

 

 

 

 

(Stop 2) Partially stops the fixed-cycle timer function

 

 

• If the fixed-cycle timer's source clock settings include an update

 

 

setting of 64 Hz, 1 Hz, or "Minute", the fixed-cycle timer function does

 

 

not operate.

 

 

∗ However, this function does operate when the fixed-cycle timer's source clock setting is

 

 

4096 Hz.

 

 

(Note) When this bit value is "1", the internal divider keeps the reset state, from 2048Hz to 1

 

 

Hz .

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