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FIBOCOM SC138-
NA
Series Hardware Guide
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Figure 3-14 LCM reference circuit
LCM design considerations:
1)
MIPI is a high-speed signal line. It is recommended to connect a common mode choke in series
near the LCD connector to improve the electromagnetic radiation interference of the circuit.
2)
MIPI route is recommended to be placed on the inner layer, and be surrounded by grounding lines in
a three-dimensional manner.
3)
The MIPI signal line needs to be controlled by a differential impedance of 100 Ω, with an error of
±10%.
4)
The total length of the route does not exceed 300 mm.
5)
The length difference of the differential lines in the set is controlled within 0.7 mm.
6)
The length difference between sets is controlled within 1.4 mm.
7)
It is recommended that the spacing between differential lines in the group should be 1.5 times the
line width, and the spacing between differential lines and other routes should be 3 times the line
width.
8)
The total stray capacitance of devices on MIPI differential signal line should not exceed 1pF.
3.16
TP
SC138 series modules provide a set of I2C interfaces that can be used to connect to the touch screen.
They also provide the power, interrupt and reset pins required by the TP. The pin definition is shown in
the following table:
Table 3-17 TP pin definition
Pin Name
Pin No.
I/O
Description
Remarks
TS0_INT_N
42
DI
TP interrupt signal
-
TS0_RST_N
43
DO
TP reset signal
-
VREG_L9A_1P8
129
PO
TP IO power supply
-
VREG_3P0
266
PO
TP VDD power supply
-
TS_I2C_SCL
41
OD
Main TP I2C clock
-
TS_I2C_SDA
150, 158
OD
Main TP I2C data
-
