2016/5/17
B
Storm BAO
Tony GAO
CHECKED BY
DRAWN BY
OF
A
6
5
4
3
2
1
SHEET
A
B
C
D
1
2
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6
D
C
B
Quectel Wireless Solutions
PROJECT
SIZE
TITLE
VER
4
3
DATE
Reference Design
L76 Series
A2
V_BCKP is designed to supply power for L76 series RTC
Indicating Circuit
Module Interface
The 1PPS indicator will blink at 1Hz frequency
Module Interface
Test Points
Charge Circuit for RTC Logic
logic circuit when VCC_MODULE_3.3V is powered off.
after fixing the position.
Reset Circuit
1. If the reset function is unused, the RESET
pin can be connected to the VCC directly.
Standby Circuit
2. Enter into standby mode: change the STANDBY pin
from high to low level.
3. Exit from standby mode: change the STANDBY pin
from low to high level.
For more details, please refer to L76 Series Hardware Design.
Schottky Diode
2. RESET has been pulled up internally.
1. STANDBY has been pulled up internally.
3. The test points are reserved for debugging the GNSS module.
2. For L76-L, pin16 and pin17 are I2C_SDA and I2C_SCL, respectively .
1. UART1 can be used to output NMEA message as well as to upgrade firmware.
For L76/L76B, pin16 and 17 are reserved,and please keep them open.
I2C Circuit for L76-L
1. I2C_SDA/I2C_SCL is pulled up to 2.8V inside L76-L moule.
There is no need to add a pull-up resistor externally.
2. The voltage threshold of I2C is 2.8V. If the system voltage
is not consistent with it,a level shifter circuit must be used.
B301
MS621FE-FL11E
R302
1K
D302
RB520S30T1G
Q301
DTC143ZEBTL
R301
1K
D301
L76_SERIES_RXD1
L76_SERIES_TXD1
GND
L76_SERIES_VCC
10
GND
11
RF_IN
12
GND
13 ANTON
14
VCC_RF
15
NC
16
RESERVED/I2C_SDA
17
RESERVED/I2C_SCL
18
FORCE_ON
9
RESET
8
VCC
7
NC
6
V_BCKP
5
STANDBY
4
1PPS
3
RXD1
2
TXD1
1
GND
U301
C302
100nF
Q302
DTC143ZEBTL
Q303
DTC143ZEBTL
C301
10uF
C303
4.7uF
C304
100nF
1
VCC
2
SDA
3
SCL
4
GND
U302
VCC_MODULE_3.3V
1PPS
TXD1_MODULE
RXD1_MODULE
VCC_MODULE_3.3V
GND
RF_IN
VCC_RF
VCC_MODULE_3.3V
RESET
GPIO_RESET
STANDBY
GPIO_STANDBY
VCC_MODULE_3.3V
V_BCKP
ANTON
RESET
VCC_MODULE_3.3V
V_BCKP
STANDBY
1PPS
TXD1_MODULE
RXD1_MODULE
FORCE_ON
I2C_SDA
I2C_SCL
I2C_SDA
I2C_SCL
VCC_MCU
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