Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

SIM900 DCD line deasserted after CLOSED

Status
Not open for further replies.

rgl

Newbie level 1
Joined
Jul 6, 2011
Messages
1
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,291
Hi @all,

i have set up a transparent TCP/IP connection with the SIM900.
All data received (binary) is forwarded to a serial port.

When the TCP/IP connection is closed (by foreign host or mobile provider or whatever) the SIM900 sends CLOSED and DCD is deasserted. Unfortunately the CLOSED response starts before the DCD line is deasserted and therefore part of the CLOSED is send to the serial port as well.

Is there some way to circumvent this behaviour (without parsing the data stream)?
Is perhaps the new AT+CIPTXISS command related to this? If not what is this command doing?
Is the behaviour perhaps changed in later FW revisions (currently using 1137B07SIM900M64_ST)? By the way is it possible to find out if there are newer versions and what has been changed (i couldn't find anything on the sim.com website)?

Best regards,
rgl
 

Hi RGL

Here is he latest build relevant to your current version, the release notes and the latest AT command reference manual. I cant be sure that this will fix your specific problem, but its worth a try.
 

Attachments

  • 1137B09SIM900M64_ST.rar
    6 MB · Views: 34
  • NDA_SIM900M64_ST Firmware Release Note.pdf
    88.1 KB · Views: 55
  • SIM900_AT Command Manual_V1.04.pdf
    2 MB · Views: 55

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top