SIM 300 connection problem on reset

[pthakkar27]

Hi

I am interfacing SIM300 with my silab microcontroller. I am facing the following issue:

1. If my controller is working and I reset my SIM300 module, I am not able to get response from SIM300. I have to physically disconnect my rs-232 cable and then plug it to make it work. However if my sim300 module is working and I reset my controller card it works fine.

2. If I start my sim300 module without SIM and then insert SIM, it is not able to register to the network. AT+CSMINS? return 0 (no sim inserted).
I need to reset the module to make it work. Does SIM300 support hot swapping of SIM card?
Can anyone help me as in why this is happening.

 

[Golden Electronics]

As per my idea Sim300 not support hot swapping of SIM card

- - - Updated - - -

Controller reset with few microsecond which SIM300 reset require few second so u require some delay to communicate with SIM300

 

[pthakkar27]

Hi Thanks for the response.

In my code I send "AT" and then wait for "OK" response from SIM300. This keeps on happening untill I receive "OK". Before sending "AT" again I have put a delay of around 3 secs. Now when I reset my SIM300 module, and send "AT" I receive some garbage values. SIM300 is not auto bauding as I have set the baudrate to 19200. This keeps on happening and when I disconnect the RS-232 cable and put it back I start receiving the correct response.

 

[Golden Electronics]

What default Baud Rate ? I thing it may 9600 & it require to store in sim cont.. even power off so when it power on then it may work at 19200.
After u remove cable & connect it again during that it may be some auto detection routine work & u get reply .................