[lwip-users] Re Help PPP-LWIP

[Andreas Stenius]

> I want to test the ppp part of the lwip stack on ucos-ii with
> Mitsubishi's
> M16C MCU? Can anyone help me what I should do first to test the
> ppp stack? I
> have the port of lwip for ucos-ii and the ppp stack for lwip? I
> have a serial
> modem, which functions should I call to send the packets which I have got
> from the uart?
> Thanks
> Erhan
>


Hi Erhan,

You need to implement the three ppp serial functions that the PPP stack is
using for sending and receiving it's data. The interface-part is taken care
of by the stack, so it's pretty straight forward.

Open up your GPRS connection ( I assume that its a GPRS connection you're
trying to use ) with the AT command "AT+CGDATA" and wait for the "CONNECT"
response string indicating that you can now start send data over your GPRS
connection. You may have to do some settings before connecting, depending on
your modem and network operator. ( See GSM 07.07 for related AT-commands ).
The manual for your modem should also have info on this. An alternative to
AT+CGDATA is the call string "ATD*99#", which is the 'modem compatibility'
function to request a GPRS connection.

When the modem is in data mode, you can start up the PPP stack, and it will
add a new 'pp'-interface for you. When that is done, the stack is ready to
open connections over your GPRS connection.

A side note on GPRS ( as it works with my operator in sweden ): I can
connect to remote addresses, but they can't connect to me ( don't get a
public IP-address, unless paid for ), since I'm behind firewalls, NAT and I
don't know all they've put in there.

Hope this helps.

Regards,
Andreas

( hope it gets through this time.. )