Datasheet

Section 10 Realtime Clock (RTC)
Rev. 1.50 Sep. 18, 2007 Page 188 of 584
REJ09B0240-0150
10.2 Input/Output Pin
Table 10.1 shows the RTC input/output pin.
Table 10.1 Pin Configuration
Name Abbreviation I/O Function
Clock output TMOW Output RTC divided clock output
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.