Renesas rl78 User Manual

Page of 1004
 
RL78/G1A 
 
CHAPTER  7   REAL-TIME  CLOCK 
7.3.8  Day count register (DAY) 
The DAY register is an 8-bit register that takes a value of 1 to 31 (decimal) and indicates the count value of days.  
It counts up when the hour counter overflows. 
This counter counts as follows. 
 
•  01 to 31 (January, March, May, July, August, October, December) 
•  01 to 30 (April, June, September, November) 
•  01 to 29 (February, leap year) 
•  01 to 28 (February, normal year) 
 
When data is written to this register, it is written to a buffer and then to the counter up to two cycles of f
RTC
 later.  Even if 
the hour count register overflows while this register is being written, this register ignores the overflow and is set to the 
value written.  Set a decimal value of 01 to 31 to this register in BCD code. 
<R> 
The DAY register can be set by an 8-bit memory manipulation instruction. 
Reset signal generation clears this register to 01H. 
 
Figure 7-9.  Format of Day Count Register (DAY) 
 
Address: FFF96H     After reset: 01H     R/W 
Symbol 
7 6 5 4 3 2 1 0 
DAY 
0  DAY20 
DAY10 DAY8 DAY4 DAY2 DAY1 
 
Caution  When it reads or writes from/to the register while the counter is in operation (RTCE = 1), follow 
the procedures described in 7.4.3  Reading/writing real-time clock. 
 
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Jul 04, 2013