RX8804CE
Page - 24
ETM59E-05
8.5.5. /INT pin Operation when an Interrupt Occurs.
1)
How to identify events when the interrupt output occurs
/INT output pin is common output terminal of interrupt events of four types Wakeup timer, alarm, time update and
EVIN interrupt.
When an interrupt occurs, please read the TF, AF, UF and EF flag to confirm which types of events occurred.
2)
Processing method in case of no using /INT output.
Please keep /INT pin open.
Please set “0” to TIE, AIE, UIE and EIE bits and do poling TF, AF, UF and EF.
8.6. Wakeup Timer Interrupt Function
8.6.1. Wakeup Timer Interrupt Function
The wakeup timer interrupt generation function generates an interrupt event periodically at any wakeup set
between 244.14
µs and 32 years.
When an interrupt event is generated, the /INT pin goes to low level and “1” is set to the TF bit to report that an
event has occurred. However, 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 after the interrupt
occurs, the /INT status is automatically cleared.
/INT status changes from low-level to Hi-Z.
Example of
/INT operation
TIE =
"
1
"
TE
=
"
0
"
→
"
1
"
7.813 ms
Min.
period
TIE
=
"
1
"
→
"
0
"
Figure 14 Wakeup Timer Function
8.6.2. Wakeup Timer Interruption Registers.
The wakeup timer interrupt generation function generates an interrupt event periodically at any wakeup set
between 244
.14 s and 16777215 minutes.
Table 44 Wakeup Timer Register
Address
Function
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
Read Write
0B
Timer Counter 0
128
64
32
16
8
4
2
1
0C
Timer Counter 1
32768
16384
8192
4096
2048
1024
512
256
0D
Control1
TEST
WADA
USEL
TE
FSEL1 FSEL0 TSEL1 TSEL0
0E
Flag Register
UF
TF
AF
VLF
VDET
Clear only
0F
Control2
CSEL1 CSEL0
UIE
TIE
AIE
RESET
1B
Timer set
TSTP
TRES
1C
Timer 0
128
64
32
16
8
4
2
1
-
1D
Timer 1
32768
16384
8192
4096
2048
1024
512
256
-
1E
Timer 2
8388608
4194304
2097152
1048576
524288
262144
131072
65536
-
1F
Timer Counter 2
8388608
4194304
2097152
1048576
524288
262144
131072
65536
•
Timer Counter 0, 1, 2 are preset value of timer.
•
Timer 0, 1, 2 are current count value of timer.
•
Before entering settings for operations, it is recommended writing a
“0” to the TE and TIE bits to prevent unexpected
hardware interrupts.
•
When the RESET bit value is
“1”
the time update interrupt function does not operate.
•
When the wakeup timer interrupt function is not using, the wakeup timer counter0, 1, 2 (0Bh, 0Ch, 1Fh), these can be
used as a RAM register. In such cases, stop the wakeup timer function by writing
“0” to the TE and TIE bits.
•
When writes 00h to all timer counter, Timer countdown are stop, and new Timer interruption are inhibited.