GSM Modem Sample Project on nRF 5340 App

RE: GSM Modem Sample Project on nRF 5340 App

Albrecht Markus Schellenberger — Tue, 09 Nov 2021 12:47:19 GMT

[quote user="code-magic"]Maybe all that I'm lacking is telling the ppp driver what device to use? I thought that was covered with 'compatible="zephyr,gsm-ppp"` in the overlay file.[/quote]

I’m honestly not quite sure where this compatible comes from. It is not included in the Zephyr devicetree by default. Can you elaborate why you have added it to your UART1?

[quote user="code-magic"]"modem not ready -116" [/quote]

-116 probably means connecting timeout, which would make sense if you are not seeing any activity one the UART pins.

Thanks and regards,

Markus

RE: GSM Modem Sample Project on nRF 5340 App

code-magic — Mon, 08 Nov 2021 14:46:38 GMT

No problem. I just plugged in a logic analyzer to the RX/TX pins and I'm not seeing any activity.

The log message below is because the modem is not sending back AT.

"modem not ready -116"

RE: GSM Modem Sample Project on nRF 5340 App

Albrecht Markus Schellenberger — Mon, 08 Nov 2021 14:25:27 GMT

Hello Justin,

my apologies for the late reply. I was out of office last week. I will have a look into this and come back to you tomorrow.

Regards,

Markus

RE: GSM Modem Sample Project on nRF 5340 App

code-magic — Tue, 02 Nov 2021 00:48:51 GMT

I finally got my head wrapped around the different UART interfaces: UART_0: terminal output, UART_1: modem. I setup the pins on UART_1; shown below.

It doesn't look like the driver knows what to use for the modem. The ppp driver, modem_gsm, and my code all show different pointers for the device.

Maybe all that I'm lacking is telling the ppp driver what device to use? I thought that was covered with 'compatible="zephyr,gsm-ppp"` in the overlay file.

&uart0 {
    status = "okay";
};

&uart1 {
	status = "okay";
    tx-pin = 3;
	rx-pin = 8;
	rts-pin = 2;
	cts-pin = 7;
	current-speed = 115200;
	gsm: gsm-modem {
		status = "okay";
		compatible = "zephyr,gsm-ppp";
		label = "modem_gsm";
	};
};

Below is the output log from the application.

[00:00:00.400,268] <dbg> net_ppp.ppp_driver_init: [0x20001d88] dev 0x20000214
[00:00:00.400,360] <dbg> modem_gsm.gsm_init: Generic GSM modem (0x20000730)
[00:00:00.400,390] <dbg> modem_gsm.gsm_init: iface->read 0x1594f iface->write 0x15985
[00:00:00.400,421] <dbg> modem_gsm.gsm_rx: starting
[00:00:00.400,482] <dbg> modem_gsm.gsm_configure: Starting modem 0x20000730 configuration
[00:00:00.400,695] <dbg> net_mgmt.net_mgmt_event_init: (main): Net MGMT initialized: queue of 2 entries, stack size of 768
[00:00:00.400,695] <dbg> net_ppp.ppp_iface_init: [0x20001d88] iface 0x20000544
[00:00:00.400,726] <dbg> net_l2_ppp.net_ppp_init: (main): Initializing PPP L2 0x20001b58 for iface 0x20000544
[00:00:00.405,303] <dbg> net_mgmt.net_mgmt_add_event_callback: (conn_mgr): Adding event callback 0x200032d8
[00:00:00.405,303] <dbg> net_mgmt.net_mgmt_add_event_callback: (conn_mgr): Adding event callback 0x200032ec
[00:00:00.405,334] <dbg> conn_mgr.conn_mgr_handler: (conn_mgr): Connection Manager started
[00:00:00.405,364] <dbg> net_l2_ppp.tx_handler: (tx_handler_thread): PPP TX started

// everthing above is before main()

[00:00:00.405,364] <inf> mux_cell_wifi: Configured: PIN_MUX_CELL_WIFI_ENABLE
[00:00:00.405,364] <inf> mux_cell_wifi: Configured: PIN_MUX_CELL_WIFI_SWITCH
[00:00:00.405,395] <inf> mux_cell_wifi: Select Cell GSM Modem
[00:00:00.405,395] <inf> gsm_modem: Configured: PIN_GSM_MODEM_STATUS
[00:00:00.405,395] <inf> gsm_modem: Configured: PIN_GSM_MODEM_DTR
[00:00:00.405,395] <inf> gsm_modem: Configured: PIN_GSM_MODEM_ON_OFF
[00:00:00.405,395] <inf> gsm_modem: Configured: PIN_GSM_MODEM_RESET
[00:00:00.405,395] <inf> gsm_modem: Turning gsm modem on via 1500ms sleep time.
[00:00:00.405,426] <inf> gsm_modem: Successfully set gsm_modem On/Off pin 1 = 1. The modem will take approximately 20 seconds to turn on and be ready for AT commands.
[00:00:01.905,487] <inf> sample_gsm_ppp: Board 'nrf5340dk_nrf5340_cpuapp' APN 'ATT' UART 'UART_1' device 0x200001b4 (modem_gsm)
[00:00:01.905,487] <dbg> sample_gsm_ppp.init_gsm_modem: GSM Device: 0x2000025c
[00:00:01.905,517] <dbg> net_mgmt.net_mgmt_add_event_callback: (main): Adding event callback 0x20002550
[00:00:02.400,726] <dbg> modem_gsm.gsm_configure: modem not ready -116
[00:00:02.400,756] <dbg> net_l2_ppp.ppp_startup: (sysworkq): PPP 0x20001b58 startup for interface 0x20000544
[00:00:02.400,756] <dbg> net_l2_ppp.ipcp_init: (sysworkq): proto IPCP (0x8021) fsm 0x20001c70
[00:00:02.400,787] <dbg> net_l2_ppp.lcp_init: (sysworkq): proto LCP (0xc021) fsm 0x20001ba0
[00:00:02.400,787] <dbg> modem_gsm.gsm_configure: Starting modem 0x20000730 configuration
[00:00:04.401,062] <dbg> modem_gsm.gsm_configure: modem not ready -116
. . . . . . 
[00:00:04.401,092] <dbg> modem_gsm.gsm_configure: Starting modem 0x20000730 configuration
[00:00:06.401,336] <dbg> modem_gsm.gsm_configure: modem not ready -116
. . . . . .

RE: GSM Modem Sample Project on nRF 5340 App

code-magic — Mon, 01 Nov 2021 13:47:59 GMT

My apologies for the long previous post and another post. The deeper I get the more I learn something. I found a command to list all devices. The output is below. Notice that `modem_gsm` is disabled.

I have a feeling this might be my issue. How do I enable modem_gsm?

`device list`

uart:~$ device list
devices:
- CLOCK (READY)
- UART_0 (READY)
- CRYPTOCELL (READY)
- sys_clock (READY)
- ppp (READY)
- GPIO_0 (READY)
- GPIO_1 (READY)
- modem_gsm (DISABLED)

`device levels` (just in case it's useful)

uart:~$ device levels
PRE KERNEL 1:
- CLOCK
- UART_0
- CRYPTOCELL
PRE KERNEL 2:
- sys_clock
POST_KERNEL:
- ppp
- GPIO_0
- GPIO_1
APPLICATION:
- None

RE: GSM Modem Sample Project on nRF 5340 App

code-magic — Sun, 31 Oct 2021 15:20:00 GMT

I'm still confused. Both with (1) is UART_0 or UART_1 being used and (2) I cannot get this working with either UART_0 or UART_1.

The overlay was set for UART_0 (&uart0), but the code sets it to UART_1. When I try setting UART_0 in prj.conf there is a fatal error and nothing is output to the console. So I set the modem to UART_0 in main.c.

UART_1: device_get_binding() returns null

 //prj.conf
 CONFIG_MODEM_GSM_UART_NAME="UART_1"
 
 //get_device_binding()
 const struct device *uart_dev =
				device_get_binding(CONFIG_MODEM_GSM_UART_NAME);
 
 //output
 <inf> sample_gsm_ppp: Board 'nrf5340dk_nrf5340_cpuapp' APN 'internet' UART 'UART_1' device (nil) (modem_gsm)

UART_0: device_get_binding() returns a device

Using your overlay and getting the device binding for "UART_0" here is my output. Also, this shows that there are no modems found.

//device_get_binding()
const struct device *uart_dev =
			device_get_binding("UART_0");

//output
<inf> sample_gsm_ppp: Board 'nrf5340dk_nrf5340_cpuapp' APN 'internet' UART 'UART_1' device 0x200001f0 (modem_gsm)
uart:~$ modem list
Modem receivers:
None found.
uart:~$ sample resume
Please wait for network connection.

I was optimistic that even though the uart command `modem list` did not return this modem that maybe it is registered in the system. So I moved code from the http_get sample project to this modem project to make an HTTP request, but it failed to get a network connection.

I'm not sure where to go from here. Is there an option for phone support or is it strictly forum support available?

Thanks

Edit:

To add on to this reply, I uncommented a few items in the prj.conf file. The most notable output to me is `modem_gsm.gsm_init: iface uart error -19`.

Please note the modem is connected via a multiplexor that must be switched on to select the modem; which is why there's log output for 'mux_cell_wifi: Select Cell GSM Modem'. This is being switched (selected) before any calls to get_device_binding().

Maybe specific calls must be made after the switch to the modem to properly configure the device and make it available?

Uncommented in prj.conf:

CONFIG_LOG_BUFFER_SIZE=16384
CONFIG_LOG_STRDUP_BUF_COUNT=200
CONFIG_MODEM_LOG_LEVEL_DBG=y
CONFIG_NET_PPP_LOG_LEVEL_DBG=y
CONFIG_NET_L2_PPP_LOG_LEVEL_DBG=y
CONFIG_NET_MGMT_EVENT_LOG_LEVEL_DBG=y
CONFIG_NET_CONNECTION_MANAGER_LOG_LEVEL_DBG=y

New Output:

uart:~$ *** Booting Zephyr OS build v2.6.0-rc1-ncs1  ***


[00:00:00.398,803] <dbg> net_ppp.ppp_driver_init: [0x20001d48] dev 0x200001d0
[00:00:00.398,895] <dbg> modem_gsm.gsm_init: Generic GSM modem (0x200006f0)
[00:00:00.398,925] <dbg> modem_gsm.gsm_init: iface uart error -19
[00:00:00.398,986] <dbg> net_mgmt.net_mgmt_event_init: (main): Net MGMT initialized: queue of 2 entries, st          ack size of 768
[00:00:00.398,986] <dbg> net_ppp.ppp_iface_init: [0x20001d48] iface 0x20000500
[00:00:00.399,017] <dbg> net_l2_ppp.net_ppp_init: (main): Initializing PPP L2 0x20001b18 for iface 0x200005          00
[00:00:00.399,078] <dbg> net_l2_ppp.ppp_startup: (sysworkq): PPP 0x20001b18 startup for interface 0x2000050          0
[00:00:00.399,078] <dbg> net_l2_ppp.ipcp_init: (sysworkq): proto IPCP (0x8021) fsm 0x20001c30
[00:00:00.399,108] <dbg> net_l2_ppp.lcp_init: (sysworkq): proto LCP (0xc021) fsm 0x20001b60
[00:00:00.403,717] <dbg> net_mgmt.net_mgmt_add_event_callback: (conn_mgr): Adding event callback 0x20003298
[00:00:00.403,717] <dbg> net_mgmt.net_mgmt_add_event_callback: (conn_mgr): Adding event callback 0x200032ac
[00:00:00.403,747] <dbg> conn_mgr.conn_mgr_handler: (conn_mgr): Connection Manager started
[00:00:00.403,747] <dbg> net_l2_ppp.tx_handler: (tx_handler_thread): PPP TX started
[00:00:00.403,778] <inf> mux_cell_wifi: Configured: PIN_MUX_CELL_WIFI_ENABLE
[00:00:00.403,778] <inf> mux_cell_wifi: Configured: PIN_MUX_CELL_WIFI_SWITCH
[00:00:00.403,778] <inf> mux_cell_wifi: Select Cell GSM Modem
[00:00:00.403,808] <inf> gsm_modem: Configured: PIN_GSM_MODEM_STATUS
[00:00:00.403,808] <inf> gsm_modem: Configured: PIN_GSM_MODEM_DTR
[00:00:00.403,808] <inf> gsm_modem: Configured: PIN_GSM_MODEM_ON_OFF
[00:00:00.403,808] <inf> gsm_modem: Configured: PIN_GSM_MODEM_RESET
[00:00:00.403,808] <inf> gsm_modem: Turning gsm modem on via 1500ms sleep time.
[00:00:00.403,808] <inf> gsm_modem: Successfully set gsm_modem On/Off pin 1 = 1. The modem will take approx          imately 20 seconds to turn on and be ready for AT commands.
[00:00:01.903,900] <inf> sample_gsm_ppp: Board 'nrf5340dk_nrf5340_cpuapp' APN 'internet' UART 'UART_1' devi          ce 0x20000188 (modem_gsm)
[00:00:01.903,930] <dbg> net_mgmt.net_mgmt_add_event_callback: (main): Adding event callback 0x20002510
uart:~$ modem list
Modem receivers:
None found.

RE: GSM Modem Sample Project on nRF 5340 App

Albrecht Markus Schellenberger — Fri, 29 Oct 2021 12:27:06 GMT

[quote user="code-magic"]Thank you so much for the details and links. I will try and test this soon. [/quote]

My pleasure! :-)

[quote user="code-magic"]Can the modem be run asynchronously? If not, what is the best practice to run the modem on the app core without blocking other processes?[/quote]

I’m not familiar with the Nimbelink LTE modem, so not sure if I can provide you with an answer here. But looking at the Software Guideline, I get the impression that everything will be controlled by AT commands via UART. So my first thought would be to use interrupt driven UART, as this will not block the application on the nRF53 and serve incoming data right away.

Regards,

Markus

RE: GSM Modem Sample Project on nRF 5340 App

code-magic — Fri, 29 Oct 2021 05:14:24 GMT

Thank you so much for the details and links. I will try and test this soon.

Can the modem be run asynchronously? If not, what is the best practice to run the modem on the app core without blocking other processes?

A problem we've ran in with other boards is that the network transaction blocks a more important process.

RE: GSM Modem Sample Project on nRF 5340 App

Albrecht Markus Schellenberger — Thu, 28 Oct 2021 07:54:12 GMT

Hello,

[quote user="code-magic"]Is this correct for the pin number for TX: `tx-pin = <3>;`?[/quote]

In your case, the .overlay should look like this:

&uart0 {
    status = "okay";
    tx-pin = <3>;
	rx-pin = <8>;
	rts-pin = <2>;
	cts-pin = <7>;
};

[quote user="code-magic"]The modem will be ran from the net core on non standard pins for TX, RX, RTS, & CTS. Given this, do I need to only need to set the pins in my overlay file for UART 0. Or will setting this for UART1 on net core be ok?[/quote]

Please be aware that the app core has to give the net core permission for each pin it wants to use, as illustrated in the nRF5340: Empty firmware for application core sample. I’m not quite sure how sufficient it will work having the GSM modem connected to the net core, as it in general is not designed for this kind of usage. So my recommendation would be to use the app core instead.

Regards,

Markus

RE: GSM Modem Sample Project on nRF 5340 App

code-magic — Wed, 27 Oct 2021 17:27:21 GMT

Thank you, this helps some. I have new found information if you can help me out with this. The modem will be ran from the net core on non standard pins for TX, RX, RTS, & CTS. Given this, do I need to only need to set the pins in my overlay file for UART 0. Or will setting this for UART1 on net core be ok?

Custom Pins:

TX: P 0.03
RX: P0.08
RTS: P0.02
CTS: P0.07

The default config for UART 0 is below, nrf5340dk_nrf5340_cpunet.dts. Note, I'm not sure how to get the `<` & `>` in the code below.

Is this correct for the pin number for TX: `tx-pin = <3>;`?

From Zephyr:

&uart0 {
	status = "okay";
	current-speed = <  115200  >;
	tx-pin = <33>;
	rx-pin = <32>;
	rx-pull-up;
	rts-pin = <11>;
	cts-pin = <10>;
	cts-pull-up;
};

Custom Overlay:

&uart0 {
	status = "okay";
	tx-pin = 3;
	rx-pin = 8;
	rts-pin = 2;
	cts-pin = 7;
};

RE: GSM Modem Sample Project on nRF 5340 App

Albrecht Markus Schellenberger — Mon, 25 Oct 2021 14:35:23 GMT

Hello Justin,

[quote user=""]I'm not sure if this is a configuration issue or if the modem is not up when `device_get_binding()` is called. What am I missing?[/quote]

First of all, you might not want to change the compatible of the UART since that will make the peripheral non-functional.

The sample uses UART_1, which is disabled for nrf5340_cpuapp by default.

uart1: arduino_serial: uart@9000 {
				compatible = "nordic,nrf-uarte";
				reg = < 0x9000 0x1000 >;
				interrupts = < 0x9 0x1 >;
				status = "disabled";
				label = "UART_1";
				current-speed = < 0x1c200 >;
				tx-pin = < 0x21 >;
				rx-pin = < 0x20 >;
			};

To enable it, you have to enable the periperhal in your overlay file:

&uart1 {
    status = "okay";
};

With this change, the samples provides the following output on my nRF5340 DK, which looks correct to me:

Velkommen til minicom 2.8

MULIGHETER: I18n 
Port /dev/ttyACM2, 16:10:55

Trykk CTRL-A Z for hjelp om spesialtaster

*** Booting Zephyr OS build v2.6.99-ncs1  ***


[00:00:00.434,051] <inf> sample_gsm_ppp: Board 'nrf5340dk_nrf5340_cpuapp' APN 'internet' UART 'UART_1' device 0x1631c (modem_gsm)
uart:~$

I hope this will help you.

Regards,

Markus

RE: GSM Modem Sample Project on nRF 5340 App

code-magic — Sat, 23 Oct 2021 12:12:22 GMT

I've made some progress. I created the project in Segger and moved my nrf5340dk_nrf5340_cpuapp.overlay file to the project. I changed the UART label to UART_1. I see that device_get_binding() is now returning a valid device for both uart_dev & gsm_dev. The event_handler() is never called so I guess the modem never connects. Is there a way for me to see what's going on behind the scenes deeper than the debug point never being hit?

I'm confused now because this project accepts UART commands and the modem is also on UART. When I enter a command (resume/suspend) with putty connected to COM4 of the device I get a 'command not found' error. I'm afraid that uart_dev and gsm_dev is the same device according to the overlay file.

Is my overlay file correct? There is a power light on the modem so I know it's on, the event_handler() just isn't being called.