SIM300 spontaneous reset

[carel101]

sim300 reset module

Hi there

I am trying to us the SIM300 module for GPRS communications.
I can turn on the module, send and receive SMS without a hitch. (This has been working very well for some time now)

But when I send AT+CGDCONT, the module resets. Sometimes it will survive the AT+CGDCONT command, only to reset the moment I send AT+CSTT.

I have tried to make 100% that this is not a power supply issue, by connecting a bunch of low ESR caps and a laboratory power supply in parallel with VBATT, and the voltage is about 4.2V. Ripple on the supply never seems to go above 200 or 300mV.

Is power supply issues the ONLY thing that can cause this behaviour?

Then, does anyone know of a nice tutorial explaining the necessary AT-command steps to communicate with an SMTP server.

Any help greatly appreciated

kind regards
Carel

 

[prd]

sim300 noise reset

Hi Carel,

I'm also faced with similar problem.
Sometime my module reset when I send

at+cipstart="TCP","xxx.xxx.xxx.xxx","yy"

or

at+cipsend=zz

I note that this problem occur after my office turn of air condition for 3 hours.
I read module temperature by at+cmte? and found that this problem occur when module temperature rise above 35

Are there anyone have solution to this problem ?

prd

 

[carel101]

turn on sim300

I have since found that it IS my power supply giving the problems. The supply needs of the SIM300 during GPRS is much different than normal mode. Your suipply MUST be able to supply 2A spikes for several milliseconds (I think 2 or 3ms).

I think when the temperature rises ,your power supply does not work as well anymore, and that is why the SIM300 starts to reset..

kind regards
Carel

 

[gravi]

sim300 reset

Hi
pay special attention to the supply power when you are designing your applications and make sure that the input voltage will never drops below 3.4V even in a transmit burst during which the current consumption may rise up to 2A. If the power voltage drops below 3.4V, the module may be switched off. Your supply track should be with sufficeint Width and thickness to carry 2A during transmit burst and searching for signal.

With Regards,
Ravi

 

[prd]

sim300 reset

Hi All,

In my case, my mcu use internal oscillator, which is very temperature sensitive. After the temp changed, the frequency of the oscillator changed, which result in baud rate changed.

prd