EZ80L92MCU Datasheet, PDF (117/241 Pages) Zilog, Inc. – eZ80Acclaim Flash Microcontrollers

eZ80L92 MCU
Product Specification
102
Real-Time Clock Alarm Control Register
This register contains alarm enable bits for the real-time clock. The RTC_ACTRL register
is cleared by a RESET. See Table 50.
Table 50. Real-Time Clock Alarm Control Register (RTC_ACTRL = 00ECh)
Bit
7
6
5
4
3
Reset
0
0
0
0
0
CPU Access
R
R
R
R R/W
Note: X = Unchanged by RESET; R/W = Read/Write; R = Read Only.
2
0
R/W
1
0
R/W
0
0
R/W
Bit
Position
[7:4]
3
ADOW_EN
2
AHRS_EN
1
AMIN_EN
0
ASEC_EN
Value Description
0000 Reserved.
0
The day-of-the-week alarm is disabled.
1
The day-of-the-week alarm is enabled.
0
The hours alarm is disabled.
1
The hours alarm is enabled.
0
The minutes alarm is disabled.
1
The minutes alarm is enabled.
0
The seconds alarm is disabled.
1
The seconds alarm is enabled.
Real-Time Clock Control Register
This register contains control and status bits for the real-time clock. Some bits in the
RTC_CTRL register are cleared by a RESET. The ALARM flag and associated interrupt
(if INT_EN is enabled) are cleared by reading this register. The ALARM flag is updated
by clearing (locking) RTC_UNLOCK or by an increment of the RTC count. Writing to the
RTC_CTRL register also resets the RTC count prescaler allowing the RTC to be synchro-
nized to another time source.
SLP_WAKE indicates if an RTC alarm condition initiated the CPU recovery from SLEEP
mode. This bit can be checked after RESET to determine if a sleep-mode recovery is
caused by the RTC. SLP_WAKE is cleared by a Read of the RTC_CTRL register.
Setting BCD_EN causes the RTC to use BCD counting in all registers including the alarm
set points.
CLK_SEL and FREQ_SEL select the RTC clock source. If the 32 KHz crystal option is
selected the oscillator is enabled and the internal prescaler is set to divide by 32768. If the
power-line frequency option is selected, the prescale value is set by FREQ_SEL, and the
32 Khz oscillator is disabled. See Table 51.
PS013012-1004
PRELIMINARY
Real-Time Clock