Datasheet
Section 10 Realtime Clock (RTC) 
    Rev. 3.00 Mar. 15, 2006 Page 149 of 526 
   REJ09B0060-0300 
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. 










