RA8804 CE
Page - 8
ETM60E-02
8.2. Details of Registers
8.2.1. Clock counter (SEC - HOUR)
Address
Function
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
00
SEC
40
20
10
8
4
2
1
01
MIN
40
20
10
8
4
2
1
02
HOUR
20
10
8
4
2
1
“o” indicates write-protected bits. A zero is always read from these bits.
The clock counter counts seconds, minutes, and hours.
The data format is BCD format. For example, when the
“seconds” register value is “0101 1001” it indicates
59 seconds.
Note with caution that writing non-existent time data may interfere with normal operation of the clock
counter.
1) Second counter
Address
Function
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
00
SEC
40
20
10
8
4
2
1
This second counter counts from
“00” to “01”, “02”, and up to 59 seconds, after which it starts again from
00 seconds.
When written data to a second register, less than a Second counter (512 Hz from 2 Hz) is cleared to zero.
When more highly precise time synchronization is needed, RESET bit is most suitable. When 60
seconds were written to a second register, it returns to 00 second in next update. This special update is
the same as plus-adjustment of leap second. This behavior is useful in the adjustments of Leap
seconds.
2) Minute counter
Address
Function
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
01
MIN
40
20
10
8
4
2
1
This minute counter counts from
“00” to “01”, “02”, and up to 59 minutes, after which it starts again from 00
minutes.
3) Hour counter
Address
Function
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
02
HOUR
20
10
8
4
2
1
This hour counter counts from
“00” hours to “01”, “02””o indicates write-protected bits. A zero is always
read from these bits.
