TinyGSM Add support for SIMCOM 7020 LTE-M/NB IoT module

Per request in #277

May 08 '19 15:05 SRGDamia1

That would be great, thumb up!

Sep 20 '19 17:09 geologic

Has anyone tested this? The manufacturer claim to be somewhat compatible with SIM800C.

Oct 25 '19 10:10 jonnor

Has anyone tested this? The manufacturer claim to be somewhat compatible with SIM800C.

Well, not sure what manufacturer claims, but it is not. Some AT commands are different and the HTTP stack is also different. For example,

retrieve IMEI: SIM800 - AT+CGSN SIM7020 - AT+GSN

registration status: SIM800 - AT+CREG SIM7020 - AT+CGREG

register APN SIM800 - AT+CSTT="apn","user","pass" SIM7020 - AT+CSGACT=1,1,"apn"

Oct 25 '19 15:10 geologic

I've skimmed the documentation. I think the entire set of TCP commands is different.

Oct 25 '19 18:10 SRGDamia1

I was trying to implement this yesterday, the basic stuff works, but i am completely struggling with the http stuff (trying to test this in AT Command tester before actually coding and am unable to get a working http connection with it)

The base set of SIM800 commands seems to be working for it, apart from some small differences but i have not found a working alternative for the SAPBR stuff.

Current major issue: -> need to wait for DNS lookup AT+CDNSGIP="vsh.pp.ua" before starting a TCP connection AT+CIPSTART="TCP","vsh.pp.ua","80" and can't manage that with waitResponse somehow

if this works, the basic WebClient Example should run (connect to IP already works, but most ngnix hosts do not accept that and redirect to a 404 error)

Fork is here: https://github.com/captFuture/TinyGSM

Dec 13 '19 07:12 captFuture

SIM7020 seems to have a different HTTP stack, to make a HTTP POST request i use this sequence (not all AT commands are mandatory):

AT AT+CGSN AT+CSQ AT+CGREG? AT+COPS? AT*MCGDEFCONT="IP"," apn_here" AT+CHTTPCREATE="http://myserver.com" AT+CHTTPCON=0 AT+CHTTPSEND=0,1,"/data/mysensor.php",436f6e6e656374696f6e3a204b6565702d416c6976650d0a,"application/octet-stream",68656c6c6f20776f726c64 AT+CHTTPDISCON=0 AT+CHTTPDESTROY=0

The first HEX part of CHTTPSEND is the header and must be terminated with 0D0A (CRLF) The second HEX part is the data you want to send.

The response for that command is sent in 2 parts, like this:

+CHTTPNMIH:0,0,800,Date: Tue, 10 Apr 2018 07:24:25 GMT Server: Apache/2.0.58 (Win32) PHP/5.2.11 Last-Modified: Fri, 16 May 2014 01:01:31 GMT ETag: "282e-45-f4410fef" Accept-Ranges: bytes Content-Length: 69 Content-Type: text/html

+CHTTPNMIC:0,0,69,138,3c736372697074206c616e67756167653d6a6176617363726970743e6c6f636174696f6e2e687265663d27657370636d732f696e6465782e706870273c2f7363726970743e

If you manage to make it work let me know.

Dec 18 '19 09:12 geologic

support for sim7020 seems to be only for gprs it seems....no nb-iot support