Quectel EG915N-EU - USB modem Port

I am using the EG915N-EU module connected to the STM32 via the USB interface. After starting the USB port, specifically the USB Modem port, the device sends the following messages:

C_SDK_1.010.064 , Mar 16 2022 16:04:23M_CAT1GSM_L1_SDK_1.010.064 , Mar 16 2022 16:04:23 ?Ô|@ RLët5ússages due to: EXT is: 24820Qd9c0, sz: 3072
rts value=0 not set success
_modem_router_internal: msg from 0, len 8, ATP index 7, modem state 0
master_sim=0, bindsim=2274,atp_index=7,from=0,len=8
is_in_raw_data_mode,150,atp_index=7,in cmd mode
(a·Rb«(utlAtParse:11697, 0, 0, 86, head=0x7ed19bfa tail=0x7ed19bed echo=0x7ed19bf2 term=0x7ed19c9d, 0x7ed19bed, 4119bfa tail=0x7ed19bed echo=0x7ed19bf2, 0x7ed19bed, 41·Rd«(utlAtParse: 11706, head=0x7ed19bfa tail=0x7ed19bed echo=0x7ed19bf2 term=0x7ed19c9d, 0x7ed19bee, 54rse: 11719, head=0x7ed19bfa tail=0x7ed19bed echo=0x7ed19bf2, 0x7ed19bee, 5451, Q=0x7ed1965c, head=0x7ed19bfa tail=0x7ed19bfa echo=0x7ed19bfa term=0x7ed19c9d, 0x7ed19bf9, D+QGPSLOC=0?Pv«(+QGPSLOC=3, num_param=1

5.3785E,0.97,177.6,3,0.000,0.661,0.357,070423,06atRespStrEx,3165,reqHandle=60325,atHandle=60325atRespStr: atHandle 0xeba5, sAtpIndex 7
] to sAtpIndex 7 doneTP: 7nssages due to: EXT is: 299967allow sleep
uec_temp_read,128,current CP g_temp=2623343
s,626,regstatus=1, need_attach=1
ent_rat,781,gSysMainMode=17,gSysMode=17,current_rat=3, need_attach=1
,L en=0
check qsclk bit 3
rocess,1845,u/qsclk can not execute
¸R/Š._quec_malloc,29,[quec_sio.c, 1268] p_new: 0x7edcd9c0, sz: 3072
=0 not set success
ter_internal: msg from 0, len 7, ATP index 7, modem state 0
=0, bindsim=2dex=7,from=0,len=7
data_mode,150,atp_index=7,in cmd mode

Parse:11697, 0, 0, 7ed198d4 tail=0x7ed198cd echo=0x7ed198cd term=0x7ed19c9d, 0x7ed198cd, 410x7ed198cd echo=0x7ed198cd, 0x7ed198cd, 41Parse: 11706, head=0x7ed198d4 tail=0x7ed198cd echo=0x7ed198cd term=0x7ed19c9d, 0x7ed198ce, 54 head=0x7ed198d4 tail=0x7ed198cd echo=0x7ed198cd, 0x7ed198ce, 54tParse:11933, 1, 0, 71965c, head=0x7ed198d4 tail=0x7ed198d4 echo=0x7ed198d4 term=0x7ed19c9d, 0x7ed198d3, Dcç..quec_regstatus_asr2quec,501,asr_status=1
tatus,626,regstatus=1, need_attach=0
current_rat,781,gSysMainMode=17,gSysMode=17,current_rat=3, need_attach=0
nssages due to: EXT is: 30264Qd9c0, sz: 3072
rts value=0 not set success
_modem_router_internal: msg from 0, len 3, ATP index 7, modem state 0
master_sim=0, bindsim=2274,atp_index=7,from=0,len=3
is_in_raw_data_mode,150,atp_index=7,in cmd mode
4autlAtParse:11697, 0, 0, 3ad=0x7ed19bdc tail=0x7ed19bd9 echo=0x7ed19bd9 term=0x7ed19c9d, 0x7ed19bd9, 41 tail=0x7ed19bd9 echo=0x7ed19bd9, 0x7ed19bd9, 41utlAtParse: 11706, head=0x7ed19bdc tail=0x7ed19bd9 echo=0x7ed19bd9 term=0x7ed19c9d, 0x7ed19bda, 5411719, head=0x7ed19bdc tail=0x7ed19bd9 echo=0x7ed19bd9, 0x7ed19bda, 544utlAtParse:11933, 1, 0, 3Qd9c0, sz: 3072
rts value=0 not set success
_modem_router_internal: msg from 0, len 4, ATP index 7, modem state 0
master_sim=0, bindsim=2274,atp_index=7,from=0,len=4
is_in_raw_data_mode,150,atp_index=7,in cmd mode
4a4utlAtParse:11697, 0, 0, 4ead=0x7ed19be0 tail=0x7ed19bd9 echo=0x7ed19bdc term=0x7ed19c9d, 0x7ed19bd9, 410 tail=0x7ed19bd9 echo=0x7ed19bdc, 0x7ed19bd9, 414utlAtParse: 11706, head=0x7ed19be0 tail=0x7ed19bd9 echo=0x7ed19bdc term=0x7ed19c9d, 0x7ed19bda, 54 11719, head=0x7ed19be0 tail=0x7ed19bd9 echo=0x7ed19bdc, 0x7ed19bda, 54X4utlAtParse:11933, 1, 0, 4Q=0x7ed1965c, head=0x7ed19be0 tail=0x7ed19be0 echo=0x7ed19be0 term=0x7ed19c9d, 0x7ed19bdf, DSQ?0/X4quec_regstatus_asr2quec,501,asr_status=1
et_regstatus,626,regstatus=1, need_attach=0
ec_get_current_rat,781,gSysMainMode=17,gSysMode=17,current_rat=3, need_attach=0
csq] info_temp->rssi=42,rsrp=-95
=60750ATPMode 1, bEnable 1+CSQ: 23,99
+CSQ: 23,99
] to sAtpIndex 7 done: on ATP: 7Id=2,lastChnlId=2d=38irstChnlId=9,lastChnlId=13lastChnlId=49nssages due to: EXT is: 41223Qd9c0, sz: 3072

What do they testify to?
How can I use the EG915N-EU chip to exchange data between the server and the STM32? Is there any documentation describing the data exchanged on the USB Modem port?

Hi Michal_Stec,

Have you already made it succuess to send and accept AT between STM32 and EG915N?

I will send the usb interface descriptors for EG915N.
It will be better if you connect the EG915N with an Ubuntu PC, and use the command to get the usb descriptors.

cat /sys/kernel/debug/usb/devices

lsusb -v

Yes, the transmission of AT commands via USB works flawlessly. Now I would like to use the EG915N module to receive data on STM using 4G data transmission. In that case, should I send data packets directly through Interface No. 1? Should I do any additional configuration via Interface No 0? If so, what exactly needs to be configured?

Here are the USB descriptors that I read from the device after setting up the USB interface in STM32 (as you can see they are slightly different from what the datasheet you sent me shows):


The interface 0 and 1 are for network transmision.
There is some hal libraries for cdc_ether and rndis_host in the STM32.

Quectel modem also support the rndis mode.

You need set the modem:


longtengmcu/USB-HOST-driver-4G-rndis-device: STM32F429 USB HOST driver 4G rndis device, Realization of high speed Ethernet data communication。 (github.com)