eZ80L92 MCU
Product Specification
88
Real Time Clock
The real time clock (RTC) keeps time by maintaining a count of seconds, minutes, hours,
day-of-the-week, day-of-the-month, year, and century. The current time is kept in 24-hour
format. The format for all count and alarm registers is selectable between binary and
binary-coded-decimal (BCD) operations. The calendar operation maintains the correct day
of the month and automatically compensates for leap year only when binary-coded-deci-
mal operation is enabled. A simplified block diagram of the RTC and the associated on-
chip, low-power, 32 kHz oscillator is illustrated in Figure 22. Connections to an external
battery supply and 32 kHz crystal network are also demonstrated in Figure 22.
RTC_VDD
Battery
VDD
IRQ
Real-Time Clock
ADDR[15:0]
DATA[7:0]
RTC Clock
R1
RTC_XOUT
C
System Clock
Low-Power
32 KHz Oscillator
VDD
32 KHz
Crystal
Enable
CLK_SEL
(RTC_CTRL[4])
RTC_XIN
C
Figure 22. Real Time Clock and 32 kHz Oscillator Block Diagram
PS013015-0316
Real Time Clock
ZILOG [ ZILOG, INC. ]
