Service Guide

LTE Standard Module Series
EC200U_Series_Hardware_Design 23 / 94
Backlight
adjustment
Configurable current
current sink method,
and connected to the
backlight cathode,
the brightness can
be adjusted with
current control.
Matrix Keyboard Interface
Pin Name
Pin No.
I/O
Description
DC Characteristics
Comment
USB_BOOT
115
DI
Matrix key input0
It can be multiplexed
as KEYIN0 after
startup.
KEYIN1
78
DI
Matrix key input1
1.8 V power domain.
If unused, keep it
open. The KEYIN1
cannot be pulled up
before startup.
KEYIN2
79
DI
Matrix key input2
1.8 V power domain.
If unused, keep them
open.
KEYIN3
80
DI
Matrix key input3
KEYOUT0
83
DO
Matrix key output0
KEYOUT1
84
DO
Matrix key output1
KEYOUT2
113
DO
Matrix key output2
KEYOUT3
114
DO
Matrix key output3
SD Card Interface
Pin Name
Pin No.
I/O
Description
DC Characteristics
Comment
SD_DET
23
DI
SD card detect
1.8 V power domain.
If unused, keep it
open.
SDIO1_DATA3
28
DIO
SDIO data bit 3
1.8/3.2 V power
domain.
If unused, keep them
open.
SDIO1_DATA2
29
DIO
SDIO data bit 2
SDIO1_DATA1
30
DIO
SDIO data bit 1
SDIO1_DATA0
31
DIO
SDIO data bit 0
SDIO1_CLK
32
DO
SDIO clock