Datasheet

Section 10 Realtime Clock (RTC)
Rev.5.00 Nov. 02, 2005 Page 143 of 500
REJ09B0027-0500
10.3 Register Descriptions
The RTC has the following registers.
• Second data register/free running counter data register (RSECDR)
• Minute data register (RMINDR)
• Hour data register (RHRDR)
• Day-of-week data register (RWKDR)
• RTC control register 1 (RTCCR1)
• RTC control register 2 (RTCCR2)
• Clock source select register (RTCCSR)
10.3.1 Second Data Register/Free Running Counter Data Register (RSECDR)
RSECDR counts the BCD-coded second value. The setting range is decimal 00 to 59. It is an 8-bit
read register used as a counter, when it operates as a free running counter. For more information
on reading seconds, minutes, hours, and day-of-week, see section 10.4.3, Data Reading Procedure.
Bit Bit Name
Initial
Value R/W Description
7 BSY — R RTC busy
This bit is set to 1 when the RTC is updating (operating)
the values of second, minute, hour, and day-of-week data
registers. When this bit is 0, the values of second, minute,
hour, and day-of-week data registers must be adopted.
6
5
4
SC12
SC11
SC10
—
—
—
R/W
R/W
R/W
Counting ten’s position of seconds
Counts on 0 to 5 for 60-second counting.
3
2
1
0
SC03
SC02
SC01
SC00
—
—
—
—
R/W
R/W
R/W
R/W
Counting one’s position of seconds
Counts on 0 to 9 once per second. When a carry is
generated, 1 is added to the ten’s position.