Real-Time Clock (Rtc) - LG KG195 Service Manual

4.2.10 REAL-TIME CLOCK (RTC)

RTC is the feature to count "second".
MTK6226's clock generation on 32.768kHz is made by OSC(X401 in 7332), connecting to
OSC32K_IN/ OSC32K_OUT and supply the clock to 6305.
C402
22pF_5%
0402C-S
X401
32.768KHZ
3
SSP-T7-F
2
C401
22pF_5%
0402C-S
The real-time clock (RTC) is driven by a 32.768 kHz clock from a crystal oscillator. The input clock is
divided by 32.768 to generate a clock with a 1 second period. In addition, it can generate interrupts at
a programmed time. The following are basic function of RTC:
-Time information (seconds/minutes/hours) coded in BCD
-Calendar information (Day/Month/Year/Day of the week) directly in BCD code up to year 2099.
-Alarm function with interrupts generation bases on a periodical
(second/minute/hour/day) or a precise time event in the century (second accuracy).
-30s time range correction
-32khz oscillator frequency gauging.
The RTC module of 7332 is supplied by 3V Backup Battery made by Sanyo. The target of running time
of the backup battery (fully charged) is longer than two hours after the main battery is removed.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
VDD
R401
10K_5%
0402R-S
P.7 GPIO0_SWITCH
P.7 GPIO1_OP_EN
P.7 GPIO2_UR1_CTL
P.9 GPIO3_CM_PW_EN
P.7 GPIO4_FMRST
P.6 GPIO5_CAP
P.5 GPIO7_STATUS_EN
P.7,9 GPIO8_SCL
P.7,9 GPIO9_SDA
P.2 26MHZ
R403
10M_5%
P.5 BBWAKEUP
0402R-S
High driving BPI port: 4mA/8mA
P.1 HB_TX
High driving BPI port: 4mA/8mA
P.1 LB_TX
4. Circuit Description
R402
10K_5%
0402R-S
U2
GPIO0/DSP_GPO3
M19
GPIO1/DICK
L15
GPIO2/DID
L16
GPIO3/DIMS
C17
GPIO4/DSP_CLK/DSPLCK/TRASD4
A19
GPIO5/AHB_CLK/DSPLD3/TRASD3
B18
GPIO6/ARM_CLK/DSPLD2/TRASD2
B17
GPIO7/SLOW_CLK/DSPLD1/TRASD1
A18
GPIO8/DSPLD0/TRASD0
A17
GPIO9
A2
SYSCLK
B1
XOUT
C2
XIN
C1
BBWAKEUP
R404 100K_5%
D3
TESTMODE
0402R-S
/JTRST
E4
/JTRST
JTCK
E3
JTCK
JTDI
E2
JTDI
JTMS
E1
JTMS
JTDO
F5
JTDO
JRTCK
F4
JRTCK
F3
BPI_BUS0[HIGH DRIVING]
F2
BPI_BUS1[HIGH DRIVING]
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LGE Internal Use Only