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Merged
trantanen merged 1 commit into from
Oct 23, 2025
Merged

app: Don't start PPP without a request #28

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4 changes: 0 additions & 4 deletions app/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -143,10 +143,6 @@ config SM_FULL_FOTA

config SM_PPP
bool "PPP support"
help
When enabled, Serial Modem automatically brings up/down the PPP link
when the LTE link (default PDN) is connected/disconnected,
regardless of what is done with AT#XPPP.

if SM_PPP

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1 change: 1 addition & 0 deletions app/overlay-ppp-without-cmux.conf
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Expand Up @@ -6,3 +6,4 @@
# Enable modem UART backend
CONFIG_MODEM_BACKEND_UART=y
CONFIG_MODEM_BACKEND_UART_ASYNC=y
CONFIG_MODEM_BACKEND_UART_ASYNC_HWFC=y
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MarkusLassila marked this conversation as resolved.
1 change: 1 addition & 0 deletions app/scripts/sm_start_ppp.sh
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Expand Up @@ -54,6 +54,7 @@ stty -F $AT_CMUX clocal

echo "Connect and wait for PPP link..."
test -c $AT_CMUX
chat $CHATOPT -t$TIMEOUT "" "AT#XPPP=1" "OK" >$AT_CMUX <$AT_CMUX
chat $CHATOPT -t$TIMEOUT "" "AT+CFUN=1" "OK" "\c" "#XPPP: 1,0" >$AT_CMUX <$AT_CMUX

pppd $PPP_CMUX noauth novj nodeflate nobsdcomp debug noipdefault passive +ipv6 noremoteip \
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4 changes: 3 additions & 1 deletion app/src/sm_ppp.c
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Expand Up @@ -476,7 +476,7 @@ static void subscribe_cgev_notifications(void)
}
}

AT_MONITOR(sm_ppp_on_cgev, "CGEV", at_notif_on_cgev);
AT_MONITOR(sm_ppp_on_cgev, "CGEV", at_notif_on_cgev, PAUSED);

static void at_notif_on_cgev(const char *notify)
{
Expand Down Expand Up @@ -694,8 +694,10 @@ static int handle_at_ppp(enum at_parser_cmd_type cmd_type, struct at_parser *par
/* Store PPP PDN if given */
at_parser_num_get(parser, 2, &ppp_pdn_cid);
delegate_ppp_event(PPP_START, PPP_REASON_DEFAULT);
at_monitor_resume(&sm_ppp_on_cgev);
} else {
delegate_ppp_event(PPP_STOP, PPP_REASON_DEFAULT);
at_monitor_pause(&sm_ppp_on_cgev);
}
return -SILENT_AT_COMMAND_RET;
}
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32 changes: 10 additions & 22 deletions doc/app/PPP_AT_commands.rst
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Expand Up @@ -31,9 +31,8 @@ The set command allows you to start and stop PPP, and optionally define the PDN

.. note::

PPP is automatically started and stopped by |SM| when the PDN connection requested for PPP
is established and lost, respectively.
This happens even if PPP has previously been stopped or started with this command.
When a PPP start has been issued, the PPP connection is automatically activated and deactivated when the PDN connection requested for PPP is established and lost, respectively.
This will continue until a PPP stop is issued.

Syntax
~~~~~~
Expand Down Expand Up @@ -77,22 +76,12 @@ PPP with default PDN connection:

::

AT+CFUN=1

OK

// PPP is automatically started when the default PDN is activated.
#XPPP: 1,0,0

// Stop PPP.
AT#XPPP=0
// Start PPP.
AT#XPPP=1

OK

#XPPP: 0,0

// Start PPP.
AT#XPPP=1
AT+CFUN=1

OK

Expand All @@ -113,7 +102,7 @@ PPP with default PDN connection:

OK

#XPPP: 0,0
#XPPP: 0,0,0

PPP with non-default PDN connection:
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Expand All @@ -125,8 +114,7 @@ PPP with non-default PDN connection:

OK

// Start PPP with the created PDN connection. This must be before AT+CFUN=1 command or
// otherwise PPP will be started for the default PDN connection.
// Start PPP with the created PDN connection.
AT#XPPP=1,1

OK
Expand Down Expand Up @@ -172,8 +160,8 @@ If you are using CMUX, see :ref:`sm_as_linux_modem` for more information on sett

For the process described here, |SM|'s UARTs must be connected to the Linux host.

1. Get PPP running on |SM|.
To do this, start |SM| and issue an ``AT+CFUN=1`` command.
1. Start PPP with the ``AT#XPPP=1`` command.
#. Set modem to online mode with the ``AT+CFUN=1`` command.
#. Wait for ``#XPPP: 1,0,0``, which is sent when the network registration succeeds and PPP has started successfully with the default PDN connection.
#. Run the following command on the Linux host:

Expand All @@ -184,7 +172,7 @@ For the process described here, |SM|'s UARTs must be connected to the Linux host
Replace ``<PPP_UART_dev>`` by the device file assigned to the PPP UART and ``<baud_rate>`` by the baud rate of the UART that PPP is using (which is set in the :file:`overlay-ppp-without-cmux.overlay` file).
Typically, when ``uart1`` is assigned to be the PPP UART (in the devicetree overlay), the device file assigned to it is :file:`/dev/ttyACM2` for an nRF9160 DK, and :file:`/dev/ttyACM1` for the other nRF91 Series DKs.

#. After the PPP link negotiation has completed successfully, a new network interface will be available, typically ``ppp0``.
#. After the PPP link negotiation has completed successfully, |SM| will send ``#XPPP: 1,1,0`` notification over UART, and a new network interface will be available, typically ``ppp0``.
This network interface will allow sending and receiving IP traffic through the modem of the nRF91 Series SiP running |SM|.

.. note::
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6 changes: 6 additions & 0 deletions doc/migration_notes.rst
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Expand Up @@ -57,6 +57,12 @@ The following changes are mandatory to make your application work in the same wa
* Removed the ``AT#XPOLL`` command.
Use ``AT#XAPOLL`` instead.

* PPP connection must be requested using the ``AT#XPPP=1`` command to get it started when the modem is put into online mode using the ``AT+CFUN=1`` command.
The ``AT#XPPP=1`` command can be run before or after the ``AT+CFUN=1`` command.
So PPP connection is not started automatically anymore when the ``AT+CFUN=1`` command is run.
After the ``AT#XPPP=1`` command is run, the PPP connection is started when the ``AT+CFUN=1`` command is run and stopped when network is lost (for example, with ``AT+CFUN=4`` or ``AT+CFUN=0``).
When the ``AT#XPPP=0`` command is run, the PPP connection is stopped permanently.

DTR and RI GPIOs replace Power and Indicate pins
------------------------------------------------

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