Posts made by jeetS

Hi there,

I have SIM7020G COM.X NB-IOT module and I am trying to connect it with network.

I am using 12V 3A SMPS and DC-DC step down converter (3A max) to drive SIM7020G module. Also, I am using airtel sim card.

AT

OK
AT+CPIN?

+CPIN: READY

OK
AT+CSTT="airtelgprs.com,"",""

ERROR
AT+CSTT="airtelgprs.com","",""

OK
AT+
+CGREG: 0▒▒CI
+CGREG: 2

+CGREG: 0
AT+CIICR

ERROR
AT+CGREG=?

+CGREG: (0-2)

OK
AT+CSQ

+CSQ: 99,99

OK

+CGREG: 2

This is what I am getting in response and I tried to change sim card.

Thank you so much in advance

@felmue

Hi there,

Now, Module is working correctly there were few issues and solved it step by step. This solution is for someone if they found this post & they need help.

1. USB to TTL convert was not recognizing UART signals transmitted from SIM7020G module. (as it was 1.7V)
2. GND was missing between different module (MOST IMP) (Use common supply maybe PC, SMPS or something else)
3. CR should be there after command.

What I did is add Logic Level Converter module between USB to TTL converter and SIM7020G module.

NOTE: Refer datasheet of IC and do the same connection as shown in datasheet for less garbage data and proper communication.

Thank you so much Felix for your help and efforts.

@felmue

Thanks for quick response.

when I was measuring voltage between GND of USB to TTL converter and GND of COM.X module. Multimeter shows 2V. (See the illustration)

But this issue is resolved by supplying power to same power source (My PC).

I want add that when I use two different USB to TTL converters then RX LED is not blinking and that means i am not getting any response.

I think this is due to Rx pin HIGH is 1.7V only and my USB to TTL converter (using CP2102) is not recognizing 1.7V. (Just a guess)

Can you share the converter you are using?

I connected to two USB to TTL converter. One to transmit data and another one to receive the data.
and opened two different serial terminal in PuTTY.

TX LED of one converter and RX LED for another converter is still blinking but there are no data on PuTTY terminal

I also used tera term and Terminal software to verify it.

@jeets said in SIM7020G echoing even after using ATE0:

@felmue

I tried to connect the ground but the problem is there is 2V difference between Ground of USB to TTL converter and Ground of COM.X module.

How should I remove it?

I connected Green PCB and USB to TTL converter with PC (Supplying voltage via USB connector)

I am able to ON/OFF SIM7020G using AT commands but I am not getting any response in PuTTY. There are no echo in UART but also no response from SIM7020G.

I measured voltage over Tx pin of SIM7020G and its 0.9V.

Observation:

I can see both TX and RX LED blinking on my USB to TTL converter whenever I send command but not receiving data on serial monitor.

I have tried different baudrate but the issue is not solved.

Thank you so much to put your efforts and time felix!

@felmue

I tried to connect the ground but the problem is there is 2V difference between Ground of USB to TTL converter and Ground of COM.X module.

How should I remove it?

Thank you

@jeets said in SIM7020G echoing even after using ATE0:

UPDATE:

I tried AT+CPOWD=0 command and netlight stopped blinking. So, I am guessing command is being sent and accepted by SIM.

and also it can be turned on using AT+CFUN=1 command.

However, I am still getting echo in response. How can I get "OK" or "ERROR" or something else?

I don't understand why this is happening. I am using this USB to TTL converter. I changed converters too.

It is not possible to troubleshoot or program efficiently without proper responses from SIM7020G.
Thank you.

UPDATE:

I tried AT+CPOWD=0 command and netlight stopped blinking. So, I am guessing command is being sent and accepted by SIM.

and also it can be turned on using AT+CFUN=1 command.

@felmue

Oh Okay. Let me try

I think I should also include these points.

1. Do I need to connect POWERKEY to STM32 controller GPIO and Pull down it as mentioned in datasheet? (See below attached image)

2. I only connect Tx/Rx in USB to TTL convert as there is 2V difference between GND of COM.X module and USB to TTL converter.

PS: I tried settings in PuTTY but it is not working.

Thank you so much felix for support!

@felmue

Hi there,

I have tested CR,LF and EOL in the end but still getting same issue.

I tried to connect it with easyloader application but it shows "failed". I tried both 1500000 and 115200 baudrate.

What if I upload any latest firmware to sim7020G?

@felmue

Thank you for response.

Okay, I will try what you have suggested. yes, I also noticed that SIM7000 series has autobauding functionality.

I will let you know what if this resolves issue.

Thank you

@felmue

Hey, Thanks for quick response.

by default pin number 5 and 13 are Rx/Tx pin. Yes, I tried removing Rx and Tx connection and it shows no response. So, it is not echo from PuTTY.

I have tried using 115200 baud-rate and it is not working. Rx/Tx pins are connected properly.

I have also tried AT commands after removing SIM card.

Do you have any idea what should I do next? what if this is firmware issue? Do I even need firmware/firmware update? :(

Greetings,

I am getting started with SIM7020G COM.X NB-IOT module. Currently, I am interfacing this module with STM32 microcontroller.

Issue is that I am getting echo while transmitting AT command using STM32 UART. After some quick search I found that echoing can be turned OFF using "ATE0" AT command; So I tried that command but still facing same issue.

Command which I send is not being recognized as I sent reboot command but it doesn't work.

Baudrate:
I have tried 9600,115200,38400 but got the same result.

Length of cable & terminal software:
I also tried various Serial terminal software to transmit AT command via PC. cable length between Tx-Rx pin is hardly 10cm (using female-male jumper cable).

Power supply:
I am powering SIM7020G with 5V-1A supply and tried USB supply directly to that green PCB on module too.

Network status LED:
network status LED is blinking every second. I know that means module is not connected to network but atleast I should get response from SIM7020G.

I appreciate any kind of help.

Thank you so much for your time & efforts.

Note: I also tried AT&W command to save settings after using ATE0 command.

@felmue Thank you so much Felix !

Have a good day (:

Greetings everyone,

This is first time, I am using any simcom microcontroller and m5stack modules. I apologize if question is too dumb.

I want to interface COM.X SIM7020G NB-IOT module with my arduino or STM32L0RB microcontroller.

Here, I am little confused about connection between Rx Tx pins. I referred hardware design guidelines of SIM7020G and it is stated that UART is working on 1.8V. As you all know, Arduino Uno works on 5V logic and STM32 works on 3.3V logic. Due to this I need voltage logic level converter.

But I have seen people to use SIm700,800,800C,7000 breakout board without logic level converter. I am confused that should I use voltage logic level converter or voltage divider for serial communication??

Also, Is there any tutorial for beginners like me to know m5stack modules?

Thank you so much in advance for help