EC20 is not working

IoT Modules LTE Standard Module
1

Hi team,
I have my EC20 worked for the first time, but the second time I turn it on, the LED STATUS doesn’t work anymore.
Note that I have already measured the following properties:

  • Vbat=3.82V (I checked with oscilloscope and it show that the power supply is stable)
  • V(PWRKEY)=0.82V
  • V(RESET_N) =1.83V

I also set the boot_config to high level in order to boot up the board.
Did I have any problems that the LEDs couldn’t work? Any help is appreciated.

2

The pins you measured are OK, but how is the voltage of LED STATUS pin or LED?

3

The LED_STATUS is 2.3V and 3.9V, I measured at 2 poles of the LED, so it is 1.6 voltage drop of the LED_STATUS

4

pls paste your schematic of this parts here, thanks~

5

The resistor has 1k ohm
Update: when I measure it with multimeter, it has 1.2 Kohm
Untitled

6

I suggest you can check the LED characteristic - voltage drop, forward current whether they meet your design. If the current is too small, the LED will not be lit.
Or you can replace the LED to try.

7

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I think your module work abnormally, so that your voltage of STATUS is 2.3V. The pin presented high-impedence state.

8

Thanks for your help. I will check this