[lwip-users] PPPoS with Telit LE910 Modem

[gzayzay]

Hello,

I have been trying to get LwIP + PPP working with the Telit LE910 modem. I am somehow not able to get a connection over PPP.

First, I have been able to send AT Commands to the modem successfully and it is responding to all AT Commands.  When I try to setup a data connection by sending ATD*99***1#, I get the following response:

CONNECT 100000000
~ÿ}#À!}!} } }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"ÜÓ~~ÿ}#À!}!}!} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"}5Z~~ÿ}#À!}!}"} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"_È~~ÿ}#À!}!}#} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"A~~ÿ}#À!}!}$} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"Úä~~ÿ}#À!}!}%} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"}3m~~ÿ}#À!}!}&} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"Yÿ~~ÿ}#À!}!}'} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"v~~ÿ}#À!}!}(} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"?~~ÿ}#À!}!})} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"}94~~ÿ}#À!}!}*} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"S¦~~ÿ}#À!}!}+} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"/~~ÿ}#À!}!},} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"?~~ÿ}#À!}!}-} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"}?}#~~ÿ}#À!}!}.} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"U~~ÿ}#À!}!}/} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"}8~~ÿ}#À!}!}0} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"Ä}/~~ÿ}#À!}!}1} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"}-~~ÿ}#À!}!}2} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"G}4~~ÿ}#À!}!}3} }8}"}&} } } } }#}$À#}%}&=}<Å}'}"}(}"?~
NO CARRIER 
<br>

The following is what I printed of the above message in hex format. 
0d 0a 43 4f 4e 4e 45 43 54 20 31 30 30 30 30 30 30 30 30 0d 0a 7e ff 7d 23 c0 21 7d 21 7d 21 7d 20 7d 39 7d 22 7d 26 7d 20 7d 20 7d 20 7d 20 7d 23 7d 25 c2 23 7d 25 7d 25 7d 26 45 36 dc 8c 7d 27 7d 22 7d 28 7d 22 cb a0 7e 7e ff 7d 23 c0 21 7d 21 7d 22 7d 20 7d 39 7d 22 7d 26 7d 20 7d 20 7d 20 7d 20 7d 23 7d 25 c2 23 7d 25 7d 25 7d 26 45 36 dc 8c 7d 27 7d 22 7d 28 7d 22 7d 27 4d 7e 7e ff 7d 23 c0 21 7d 21 7d 23 7d 20 7d 39 7d 22 7d 26 7d 20 7d 20 7d 20 7d 20 7d 23 7d 25 c2 23 7d 25 7d 25 7d 26 45 36 dc 8c 7d 27 7d 22 7d 28 7d 22 43 7d 36 7e 7e ff 7d 23 c0 21 7d 21 7d 24 7d 20 7d 39 7d 22 7d 26 7d 20 7d 20 7d 20

7e ff 7d 23 c0 21 7d 21 7d 32 7d 20 7d 39 7d 22 7d 26 7d 20 7d 20 7d 20 7d 20 7d 23 7d 25 c2 23 7d 25 7d 25 7d 26 45 36 dc 8c 7d 27 7d 22 7d 28 7d 22 7d 32 d1 7e 7e ff 7d 23 c0 21 7d 21 7d 33 7d 20 7d 39 7d 22 7d 26 7d 20 7d 20 7d 20 7d 20 7d 23 7d 25 c2 23 7d 25 7d 25 7d 26 45 36 dc 8c 7d 27 7d 22 7d 28 7d 22 56 8a 7e

0d 0a 4e 4f 20 43 41 52 52 49 45 52 0d 0a

The modem doesn't seem to be responding the messages sent from LWIP ppp stack. The sio_read() and sio_write() functions are called and after a while, I see timeout messages. I have attached a file containing some logs information. 

pppLogs.txt

I am running FreeRTOS and a snippet of the code is as follows shown below. When the callback function is called, the error code is  PPPERR_PROTOCOL (-8)

// 4. Initialize the Lightweight IP Library (TCP/IP & PPP)             
                uint32_t waitCnt = 0;
                tcpip_init(tcpip_init_done, (void *)&lwipThreadStarted);
                
                while ((lwipThreadStarted == 0) && (waitCnt < LTE_TASK_LWIP_MAX_DELAY))
                {
                    vTaskDelay(10 / portTICK_PERIOD_MS);
                    waitCnt++;
                }
                                
                if ( waitCnt >= LTE_TASK_LWIP_MAX_DELAY)
                { // If we ever enter, reset the sensor. LWIP thread did not start
                    debug_printLine("LTE COMMS: FAILED TO START lwIP THREAD");
                    hwSystem_Reset();
                }
                
                // i+nitialize PPP. This needs to be done only once after boot up, to initialize global variables, etc.
                pppInit();
                pppSetAuth(PPPAUTHTYPE_CHAP, pAuthUN, pAuthPwd);
               
                // 5. Spawn the DNP3 Task
                taskCreate(DNP_TASK, NULL);
                
                // Allow other task to run before we enter data mode
                vTaskDelay(1500 / portTICK_PERIOD_MS);
                
                // 6. Now we can put the modem in data mode
                if ( (sensorDB.pConfigParam->cfgAPNUsername != NULL) && (sensorDB.pConfigParam->cfgAPNPassword != NULL) )
                {
                    pAuthUN     = (char *)sensorDB.pConfigParam->cfgAPNUsername;
                    pAuthPwd    = (char *)sensorDB.pConfigParam->cfgAPNPassword;
                }
                
                pppSetAuth(PPPAUTHTYPE_CHAP, pAuthUN, pAuthPwd);
               
                lStatus = lteEnterDataMode(lteModemType); // Send ATD*99***1#
                
                if ( lStatus == CPS_STATUS_OK )
                { // The modem is now set to communicate if needed
                    // 7. Open a PPP over Serial Connection   
                    lteCfgInfo.pppIsOpen = PPP_UNKNOWN;
                         
                    lteCfgInfo.pppSessionDes = pppOverSerialOpen(INTERFACE_CELL, ppp_linkStatusCB, (void *)<eCfgInfo.pppIsOpen);
                    waitCnt = 0;
                    
                    if (lteCfgInfo.pppSessionDes >= 0 )
                    {
                        debug_printLine("LTE COMMS: PPP SERIAL INITIATED");
                        
                        while ((lteCfgInfo.pppIsOpen == PPP_UNKNOWN) && (waitCnt < LTE_TASK_LWIP_MAX_DELAY))
                        {
                            vTaskDelay(500 / portTICK_PERIOD_MS);
                            waitCnt++;
                        }
                    }
           }

Could anyone kindly help point me in the right direction as to what I may be doing wrong?

Thanks,

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