RA8900 SA / CE
Page - 10
ETM44E-01
8.2.3. Alarm registers
Address
Function
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
08, 18
MIN Alarm
AE
40
20
10
8
4
2
1
09, 19
HOUR Alarm
AE
20
10
8
4
2
1
0A, 1A
WEEK Alarm
AE
6
5
4
3
2
1
0
DAY Alarm
20
10
8
4
2
1
The alarm interrupt function is used, along with the AEI, AF, and WADA bits, to set alarms for specified date, day,
hour, and minute values.
When the settings in the above alarm registers and the WADA bit match the current time, the /INT pin goes to low
level and "1" is set to the AF bit to report that and alarm interrupt event has occurred.
8.2.4. Fixed-cycle timer control registers
Address
Function
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
0B, 1B
Timer Counter 0
128
64
32
16
8
4
2
1
0C, 1C
Timer Counter 1
2048
1024
512
256
These registers are used to set the preset countdown value for the fixed-cycle timer interrupt function.
The TE, TF, TIE, and TSEL0/1 bits are also used to set the fixed-cycle timer interrupt function.
When the value in the above fixed-cycle timer control register changes from 001h to 000h, the /INT pin goes to low
level and "1" is set to the TF bit to report that a fixed-cycle timer interrupt event has occurred.
8.2.5. Extension register
Address
Function
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
0D, 1D
Extension Register
TEST
WADA
USEL
TE
FSEL1
FSEL0 TSEL1
TSEL0
(Default)
(0)
(
)
(
)
(
)
(0)
(0)
(
)
(
)
1)
The default value is the value that is read (or is set internally) after powering up from 0 V.
2)
"o" indicates write-protected bits. A zero is always read from these bits.
3)
"
" indicates a default value is undefined.
This register is used to specify the target for the alarm function or time update interrupt function and to select or set
operations such as fixed-cycle timer operations.
1) TEST bit
This is the manufacturer's test bit. Its value should always be "0".
Be careful to avoid writing a "1" to this bit when writing to other bits.
TEST
Data Description
Write/Read
0
Normal operation mode
Default
1
Setting prohibited (manufacturer's test bit)
2) WADA ( Week Alarm/Day Alarm ) bit
This bit is used to specify either WEEK or DAY as the target of the alarm interrupt function.
Writing a "1" to this bit specifies DAY as the comparison obLCct for the alarm interrupt function.
Writing a "0" to this bit specifies WEEK as the comparison obLCct for the alarm interrupt function.
3) USEL ( Update Interrupt Select ) bit
This bit is used to specify either "second update" or "minute update" as the update generation timing of the time
update interrupt function.
USEL
Data update
interrupts
Auto reset time
t
RTN
Write/Read
0
second update
Default
500 ms
1
minute update
7.813 ms
4) TE ( Timer Enable ) bit
This bit controls the start/stop setting for the fixed-cycle timer interrupt function.
Writing a "1" to this bit specifies starting of the fixed-cycle timer interrupt function (a countdown starts from a
preset value).
Writing a "0" to this bit specifies stopping of the fixed-cycle timer interrupt function.
