STEVAL-STMDLTE (BG96) MODEM LTE with NRF52840 using libuarte

RE: STEVAL-STMDLTE (BG96) MODEM LTE with NRF52840 using libuarte

user71585 — Mon, 13 Jun 2022 14:16:03 GMT

Thank you Einar.

RE: STEVAL-STMDLTE (BG96) MODEM LTE with NRF52840 using libuarte

user7377 — Mon, 13 Jun 2022 13:01:20 GMT

Hi,

As UART is asynchronous, the clock on the devices that communicate must not drift too much or bee to inaccurate, as then communication will fail (you will get framing errors, etc). This is a general issue with UART that you need to handle. Also, flow-control is very often a good idea, but for other reasons.

[quote user="ATYQ"]I it's between the PC and the modem by the uart of the modem ( NOK)[/quote]

I see. My point is that in this case you are not involving any Nordic products, as this is about communication between a PC and the modem manufactured by ST Microelectronics. This forum (DevZone) is for technical support for Nordic Semiconductor products, and not for ST product's. So for assistance on ST products (like the BG96), you need to discuss that with ST and not here.

RE: STEVAL-STMDLTE (BG96) MODEM LTE with NRF52840 using libuarte

user71585 — Fri, 10 Jun 2022 13:20:58 GMT

I did not understand a thing, why you speak of the clock because I use the asynchronous usart therefore, there is not a clock signal between the mcu and the modem, 
could you clarify me please ?

RE: STEVAL-STMDLTE (BG96) MODEM LTE with NRF52840 using libuarte

user71585 — Fri, 10 Jun 2022 13:13:53 GMT

Do you have any comments on the soft please ?

RE: STEVAL-STMDLTE (BG96) MODEM LTE with NRF52840 using libuarte

user71585 — Fri, 10 Jun 2022 13:11:23 GMT

I it's between the PC and the modem by the uart of the modem ( NOK)

RE: STEVAL-STMDLTE (BG96) MODEM LTE with NRF52840 using libuarte

user7377 — Fri, 10 Jun 2022 13:06:09 GMT

This is between your PC and the BG96, right? If so, you need to ask ST about it.

RE: STEVAL-STMDLTE (BG96) MODEM LTE with NRF52840 using libuarte

user71585 — Fri, 10 Jun 2022 13:05:58 GMT

and I have the same thing when I view the receive buffer with the nRF52 MCU

RE: STEVAL-STMDLTE (BG96) MODEM LTE with NRF52840 using libuarte

user71585 — Fri, 10 Jun 2022 13:03:52 GMT

Hi Einar,

here is the kind of data when I connect directly to the tx, rx, and gnd of the modem with an FTDI using a tool to send the data

RE: STEVAL-STMDLTE (BG96) MODEM LTE with NRF52840 using libuarte

user7377 — Fri, 10 Jun 2022 12:51:18 GMT

Hi,

[quote user="ATYQ"]I don't receive the correct data from the modem .[/quote]

In what way is it not correct? Wrong amount of data/length, or corrupted data? please elaborate. Also, what does the data look like if you log it from the nRF? Is it the same as when you dump it from the FTDI connected to a computer, or different?

[quote user="ATYQ"]and yesterday i did a test, i communicated with a direct FTDI cable on the tx, rx, gnd of the modem and PC using a tool to send AT command and i received the same incorrect data .[/quote]

It seems like you are having issues communicating with the modem also when you do not use the nRF? For that I ask you to contact ST, as that is their product and I am not able to support that.

[quote user="ATYQ"]and also at the output of the chip i measure 3,3v and at the output of the modem BG96 i measure 1,8v because there is a shifter level in schematics Link ( 8 . Schematic diagrams).[/quote]

I will just assume that this works properly, for details you need to discuss with ST.

[quote user="ATYQ"]Concerning the baudrate, when I connect in usb micro, I send the command AT : AT+IPR? it responds well 115200 and in MCU nRF52 i config the baudrate as 115200 .[/quote]

The baud rate could be wrong (meaning not the same) even if you have configured the same baud rate on all devices. If the clocks are inaccurate and too different, you will still have problems (UART is asynchronous after all).

RE: STEVAL-STMDLTE (BG96) MODEM LTE with NRF52840 using libuarte

user71585 — Fri, 10 Jun 2022 12:37:14 GMT

Hi Einar,

Thank you for your feedback .

I work on a project, the objective is to communicate nRF52840 with ( STEVAL-STMODLTE puce with modem BG96 steval-stmodlte ) .

I use an example libuarte in SDK nRF52840, the problem is that I don't receive the correct data from the modem .

I attached a screenshot of the data received . and yesterday i did a test, i communicated with a direct FTDI cable on the tx, rx, gnd of the modem and PC using a tool to send AT command and i received the same incorrect data .

By info on the chip STEVAL-STMODLTE there is a usb port to send AT commands and it works well when you connect to the micro usb port, and also at the output of the chip i measure 3,3v and at the output of the modem BG96 i measure 1,8v because there is a shifter level in schematics Link ( 8 . Schematic diagrams).

Concerning the baudrate, when I connect in usb micro, I send the command AT : AT+IPR? it responds well 115200 and in MCU nRF52 i config the baudrate as 115200 .

Thank you for your help .

Best regards,

RE: STEVAL-STMDLTE (BG96) MODEM LTE with NRF52840 using libuarte

user7377 — Fri, 10 Jun 2022 11:49:00 GMT

Hi,

[quote user=""]and sometimes the software crashes here NRF_BREAKPOINT_CON[/quote]

This is from the error handler, and if you test with a debug build you can check the file name, line number and error code. That should give you a lot to go on (see An introduction to error handling in nRF5 projects).

[quote user=""]Sniffer using FTDI[/quote]

It is not easy to say much without knowing more, but it looks like there could be a baud rate issue. Is the baud rate configuration the same on both ends? And do both sides use an accurate clock source? As you are already using the clock driver that could be accomplished on the nRF side by calling nrf_drv_clock_hfclk_request().