Epson RX-8801SA/JE - Manual (Page 14)

RX − 8801 SA / JE
Page - 11 ETM26E-03
8.2.4. Extension register (Reg-D)
Address Function bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
Extension Register TEST WADA USEL TE FSEL1 FSEL0 TSEL1 TSEL0
D
(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.
∗
If a "1" is inadvertently written to this TEST bit, there is a safety function where by this bit will be automatically cleared to zero when a STOP
condition or Repeated START condition is received or when the 0.95-second bus timeout function operates.
TEST Data Description
0 Normal operation mode ∗ Default
Write/Read
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 object for the alarm interrupt function.
Writing a "0" to this bit specifies WEEK as the comparison object 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
0 second update ∗ Default 500 ms
Write/Read
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.
5) FSEL0,1 ( FOUT frequency Select 0, 1 ) bits
The combination of these two bits is used to set the FOUT frequency.
FSEL0,1
FSEL1
(bit 3)
FSEL0
(bit 2)
FOUT frequency
0 0 32768 Hz Output ∗ Default
0 1 1024 Hz Output
1 0 1 Hz Output
Write/Read
1 1 32768 Hz Output
6) TSEL0,1 ( Timer Select 0, 1 ) bits
The combination of these two bits is used to set the countdown period (source clock) for the fixed-cycle timer
interrupt function (four settings can be made).
TSEL0,1
TSEL1
(bit 1)
TSEL0
(bit 0)
Source clock
0 0 4096 Hz /Once per 244.14 μs
0 1 64 Hz / Once per 15.625 ms
1 0 "Second" update /Once per second
Write/Read
1 1 "Minute" update /Once per minute