RX8804CE
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ETM59E-05
4) TE (Timer Enable) bit
This bit controls the start/stop setting for the wakeup timer interrupt function.
Table 48 TE bit
TE
Data
Description
Write / Read
0
Preset value loaded to all Timer counter, and count-down stops
1
Starts wakeup timer countdown
The countdown that starts when the TE bit value changes from 0
to 1 always begins from the preset
value
5) TF (Timer Flag) bit
If set to 0 beforehand, this flag bit's value changes from
“0” to “1” when a wakeup timer interrupt event has
occurred. Once this flag bit's value is
“1”, its value is retained until a “0” is written to it.
Table 49 TF bit
TF
Data
Description
Write
0
The TF bit is cleared to zero to prepare for the next status detection
Clearing this bit to zero does not enable the /INT low output status to be cleared (to Hi-Z)
.
1
Invalid (writing a 1 will be ignored)!
Read
0
Wakeup timer interrupt events are not detected.
1
Wakeup timer interrupt events are detected.
(Result is retained until this bit is cleared to zero.)
6) TIE (Timer Interrupt Enable) bit
When a wakeup timer interrupt event occurs (when the TF bit value changes from
“0” to “1”), this bit's value
specifies whether an interrupt signal is generated (/INT status changes from Hi-Z to low) or is not generated
(/INT status remains Hi-Z).
Table 50 TIE bit
TIE
Data
Description
Write / Read
0
1) When a wakeup timer interrupt event
occurs, an interrupt signal is not
generated or is canceled (/INT status remains Hi-Z)
2) When a wakeup timer interrupt event occurs, the interrupt signal is canceled
(/INT status changes from low to Hi-Z)
Even when the TIE bit value is “0” another interrupt event may change the /INT status to low (or may
hold /INT =
L)
1
When a wakeup timer
interrupt event occurs, an interrupt signal is generated (/INT
status changes from Hi-Z to low
)
When a wakeup timer interrupt event has been generated low-level output from the /INT pin occurs
only when the value of the control register's TIE bit is 1. Earliest 7.813 ms the interrupt occurs, the
/INT status is automatically cleared (/INT status changes from low to Hi-Z).
8.6.3. Wakeup Timer Start Timing
Counting down of the wakeup timer value starts at the rising edge of the SCL signal that occurs when the TE
value is changed from 0 to “1”
(after bit “0” is transferred).
Figure 16 Wakeup Timer Start Sequence