A9G leds dont blink and it doesn't respond to AT commands

Hello,
I’m currently facing an issue where my A9G module does not respond to AT commands, and none of its LEDs are blinking at all.

I connected my USB-to-serial adapter to the A9G as follows:

serial | A9G
TXD -> RX
RXD -> TX
GND -> GND
VCCIO -> VUSB

I tried several baud rates (115200 for example but i read somewhere that it doesn't operate on rates like that), but none of them worked. I also attempted to power the A9G using a micro USB cable, but that didn’t help either. The power button on the board seems to do nothing, as the LEDs never turn on.

When I experimented a bit with the wiring—for example, connecting RXD to HST_TX the LED on my CP2102 adapter turned on, but I still couldn’t get any OK response in the serial terminal.

At this point, I’m not sure whether I’m doing something wrong with the wiring or power supply, or if the A9G module might be dead.

I should also mention that I’m new to this stuff, so I would really appreciate any help or explanation.



I am adding additional screenshots down here:


image

Do you provide enough current / stable voltage through this ?

when using 3.3V


I think you might be limited to 50mA or something like that... probably not enough

You can spend weeks spinning your wheels, or you might get lucky and solve your problem quickly. To avoid unnecessary delays, it’s crucial to provide an annotated schematic of your circuit as you have it wired, showing all connections, including power, ground, and power supplies. I recommend it be in English, you can translate before posting if needed.

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You have your CP2102 board jumped for 3.3V operation.

You have VUSB hooked up to VCCIO.

VCCIO will be 3.3V.

You should think about that.

image

And are you sure about that? What does the documentation tell you?



Hi, as you can see I now have my CP2102 board jumped for 5V as you correctly pointed out and I am using a xiaomi charger as a power supply for my A9G board (don't know if that is correct that is why I uploaded a pic). I also changed the BaudRate to 115200, but it still doesnt send me "OK" response when I send the "AT" command.

The Netlight LED on A9G doesn't blink when I try to power it on using a PWR button.

I tried following these tutorials:

If you power your board separately then don’t connect VCCIO -> VUSB. Just connect GNDs

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Okay I did as you have told, but still no response after holding on the PWR button. The LED still isn't blinking (A9G) and the response I get is the same. Do I also need to adjust my jumper on CP2102 to 3.3V back? I also find it interesting that when I connected RXD (Serial) -> HST_TX (A9G) the LED on my CP2102 (RXD one) turns on but when it is pinned to an ordinary TX it doesn't. When my Serial is opened in the tool and I "play with it" meaning I unplug it and plug it again I get some gibberish in the console. I tried connecting TXD (Serial) -> HST_RX (A9G) to see if that will give me something similar but it doesnt since the LED on CP2102 corresponding to TXD isn't turning.

Is the module 3.3V or 5V ?

If you used 5V on Tx and the module expects 3.3V you might have damaged it…

Is there a way to check If I damaged it or it came as this already? When I first set it up it was without even connecting the pins to CP2102 because I didnt have it at the time. I plugged it directly to my PC using micro USB cable and tried to power it on using the PWR button which didn't make my LED blink. I did not assume at that time it might be due to not enough or not stable voltage. Anyway my Windows PC could not recognize the device, so I came to realization that I need a USB to Serial Adapter in order to make it work. It got delivered today and first thing I tried with jumper on 3.3V was connecting the pins:

Serial | A9G
RXD -> TX
TXD -> RX
GND -> GND

Power supply was still from a micro USB cable connected to my 2.0 USB PC port, but as you can imagine still no response. Therefore I kind of tried switching my configuration of connected pins and I might have moved the jumper to 5V without checking the PWR button wiith another source of power suppply (charger in my case).

I think I ordered 3.3V module, so I am almost sure I damaged it by now, but I will order a new one and do it more careful this time.

I guess the lack of knowledge always comes at a cost...

The power requirements for cellular modems are quite important (as you may have observed)

They can pull up to 2A on occasion, which is far beyond the Arduino regulators, and even some small power adapters.

This where details and schematics become important.

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Not really…