EZ80L92MCU Datasheet, PDF (103/241 Pages) Zilog, Inc. – eZ80Acclaim Flash Microcontrollers

eZ80L92 MCU
Product Specification
88
Real-Time Clock
Real-Time Clock Overview
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). The calendar operation maintains the correct day of the
month and automatically compensates for leap year. 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 demon-
strated in Figure 22.
V_DD
IRQ
Real-Time Clock
ADDR[15:0]
RTC_V_DD
Battery
DATA[7:0]
RTC Clock
R1
RTC_X_OUT
System Clock
C
Low-Power
32 KHz Oscillator
V_DD
32 KHz
Crystal
Enable
CLK_SEL
(RTC_CTRL[4])
RTC_X_IN
C
Figure 22. Real-Time Clock and 32KHz Oscillator Block Diagram
PS013012-1004
PRELIMINARY
Real-Time Clock