Epson RX8130CE - Time Update Interrupt Function; Related Registers for Time Update Interrupt Functions

14. Functions
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ETM50E-07 Seiko Epson Corporation 35
14.4. Time Update Interrupt Function
The time update interrupt function generates interrupt in one-second or one-minute intervals which are
synchronized to the update of the second or minute time register of the RTC When an interrupt event is
generated, This /IRQ status is automatically cleared (/IRQ status changes from low level to Hi-z earliest
7.57ms (maximum 15.63ms) after the interrupt occurs).
14.4.1. Related registers for time update interrupt functions.
Addressh
Function
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
1C
Extension Register
FSEL1
FSEL0
USEL
TE
WADA
TSEL2
TSEL1
TSEL0
1D
Flag Register
VBLF
0
UF
TF
AF
RSF
VLF
VBFF
1E
Control Register0
TEST
STOP
UIE
TIE
AIE
TSTP
TBKON
TBKE
 Before entering settings for operations, we recommend writing a "0" to the UIE bit to prevent hardware
interrupts from occurring inadvertently while entering settings.
 When the STOP bit value is "1"time update interrupt events do not occur.
 Although the time update interrupt function cannot be fully stopped, if "0" is written to the UIE bit, the time
update interrupt function can be prevented from changing the /IRQ pin status to low.
1) USEL bit ( Update Interrupt Select )
This bit is used to select "second" update or "minute" update as the timing for generation of time
update interrupt events.
Table 28 Second/Minute selection
2) UF bit(Update Flag)This flag bit value changes from "0" to "1" when a time update interrupt event occurs.
Table 29 Time update Flag
UF
Data
Description
Write
0
Clearing this bit to zero enables /IRQ low output to be canceled (/IRQ remains
Hi-z) when a time update interrupt event has occurred.
1
Invalid (writing a 1 will be ignored
Read
0

1
Time update interrupt events are detected.
(The result is retained until this bit is cleared to zero.)
3) UIE bit(Update Interrupt Enable)
This bit selects whether to generate an interrupt signal or to not generate it.
Table 30 Time update interrupt control
UIE
Data
Description
Write / Read
0
1) Does not generate an interrupt signal when a time update interrupt event
occurs (/IRQ remains Hi-Z)
2) Cancels interrupt signal triggered by time update interrupt event (/IRQ
changes from low to Hi-Z).
 Even when the UIE bit value is "0" another interrupt event may change the /IRQ status to low (or
may hold /IRQ ="L").
1
When a time update interrupt event occurs, an interrupt signal is generated
(/IRQ status changes from Hi-Z to low).
 When a time update interrupt event occurs, low-level output from the /IRQ pin occurs only when
the UIE bit value is "1". Earliest 7.57ms after the interrupt occurs, the /IRQ status is automatically
cleared (/IRQ status changes from low to Hi-Z).
USEL
Data
Description
Write
0
Selects "second update" (once per second) as the timing for generation of
interrupt events
1
Selects "minute update" (once per minute) as the timing for generation of
interrupt events