Interfacing Raspberry Pi 5G HAT with other controller

There is a garbage character that appears before  or after "AT\r\n", enable the checkbox of hex along with Ascii to see the unnecessary character and remove it from the code. Try to find out the reason for that, now connect the ttl to 5g modem and send the message like this. Make sure the "CR-LF" is selected under "Send on enter" dropdown option. It will automatically add "\r\n". If the modem returns OK, then you can connect ESP32 directly to Modem.

Hi. I would like to update the progress. I have tried what you suggested balajivan1995 . But it was not a success either. I tried checking the design file, and I found that there is no UART pin available. The only available interface is the USB and PCIe.

Could it be the reason why I am not able to communicate through the UART? If so, what would be the best way to communicate the 5G modulewith the controller?

Appreciate your help on this matter, shabaz  and balajivan1995 . Thank you.

I don't have any experience in PCIe communication. As for the USB, we can try two things,

1. Connect USB to UART TTL to the board and connect it to ESP32's UART and hope AT Port is accessible through it.

2. Change ESP32C3 to ESP32S3 or some other controller that supports USB host communication. 

In this section, they've mentioned UART port is accessible in 3 modules, are you sure yours is not one of them? 

Yes balajivan1995 . I using the RM502Q-AE.

I will change the controller board and try to see if it can work.

Thank you.

It may be worth first confirming operation with a Pi. According to the Waveshare website, the UART is the only interface connected to the Pi. 

If the interface really is only USB and PCIe, then there's little hope of working with ESP32. 

There is a chance that USB may work, but only if ESP32 can operate as USB Host (which I have no idea if it can, but hopefully it is documented somewhere), if the interface on the Waveshare card is USB peripheral.

Sorry for the late reply. Currently, I am confirming with Raspberry Pi.

Hi, the timing and baud rates are the problems in interfacing such as baud rate, X-on, X-off, you need to flash or program the HAT using Hyper terminal or the s/w that came with the controller. And match it with the specifications with your devices. After which you need to fully reset and turn on one device at a time.

This should then work, if not, check your C++ script language for errors. you may have to flash the correct software again to make it all match. I notice there is no [end] in the script language or [return]

Hi Sonicel ,

Thank you for the reply. Currently i am using the Raspberry to interface and verify it everything is working fine. 

Hi shabaz & balajivan1995 ,

To update on the progress. I am able to communicate with the 5G HAT with the RPI through the USB. I am able to send/receive the AT command. Currently i am trying to write a code to read temperature value and send the data to the cloud through the 5G HAT via GSM. Is there any reference or sample code that i can refer to? 

Appreciate your help on this. If you need further info please do let me know.

Thanks again.

well, since you are using USB interface, you can forget about  AT commands. Follow the instructions here to install network drivers for RPI. If the driver installation went smoothly, you will be able to access internet just like with an Ethernet or USB dongle.

As for the sending telemetry to cloud, you can write a python script that runs in background and send data at the time period you set, again no need to worry about internet connectivity if the driver installation is done properly. 

Unless you explicitly need to use in GSM mode, 5G hat is an overkill. You could use BG96 or SIM800 for that purpose.