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4. Circuit Description
LGE Internal Use Only
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
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.
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.
JRTCK
JTDI
/JTRST
JTDO
JTCK
JTMS
VDD
GPIO8_SCL
P.7,9
LB_TX
P.1
HB_TX
P.1
26MHZ
P.2
GPIO9_SDA
P.7,9
BBWAKEUP
P.5
GPIO2_UR1_CTL
P.7
GPIO3_CM_PW_EN
P.9
GPIO1_OP_EN
P.7
GPIO7_STATUS_EN
P.5
GPIO4_FMRST
P.7
GPIO5_CAP
P.6
GPIO0_SWITCH
P.7
High driving BPI port: 4mA/8mA
High driving BPI port: 4mA/8mA
X401
32.768KHZ
SSP-T7-F
1
4
2
3
R404
100K_5%
0402R-S
GPIO0/DSP_GPO3
U2
GPIO1/DICK
M19
GPIO2/DID
L15
GPIO3/DIMS
L16
GPIO4/DSP_CLK/DSPLCK/TRASD4
C17
GPIO5/AHB_CLK/DSPLD3/TRASD3
A19
GPIO6/ARM_CLK/DSPLD2/TRASD2
B18
GPIO7/SLOW_CLK/DSPLD1/TRASD1
B17
SYSCLK
A2
XOUT
B1
XIN
C2
BBWAKEUP
C1
TESTMODE
D3
/JTRST
E4
JTCK
E3
JTDI
E2
JTMS
E1
JTDO
F5
JRTCK
F4
BPI_BUS0[HIGH DRIVING]
F3
BPI_BUS1[HIGH DRIVING]
F2
/W
AT
CHDOG
R18
U
SB_
D
P
P1
6
U
SB_
D
M
P1
7
GPIO8/DSPLD0/TRASD0
A18
GPIO9
A17
R402
10K_5%
0402R-S
R401
10K_5%
0402R-S
C402
22pF_5%
0402C-S
R403
10M_5%
0402R-S
C401
22pF_5%
0402C-S