I use GPRS shield from SeeedStudio with an arduino to post data to a website.
In order to put SIM900 into sleepmode , i tried the following as a part of a code:
//Code to upload data goes here
//Enabling sleep mode in SIM900
GPRS_Serial.println("AT+CSCLK=1"); //Enable Sleep mode, slowclock
//D3 pin of Atmega used to drive DTR pin of SIM900
//Pull DTR high to put it into sleep
delay(30000); // 30sec delay where the SIM will go to sleep
digitalWrite(3, LOW); //wake up SIM900
delay(100);// a minimim of 50msec is req
I had a wire going from DTR on J11 connector to Arduino D3 to toggle DTR pin. I am using Softserial interface.
After the execution a few times, i cannot get any reponse to any AT commands and looks like GPRS board is not responding to basic AT commands anymore. I dont get an OK from AT command anymore. I had the upload code working without putting SIM900 into sleep but not anymore since there is no response from GPRS shield for the AT commands.
Anyone tried to put SIM900 into sleep mode by using this approach ? I am concerned if i have damaged the serial interface of GPRS board. But I can see that the network registration is done from the flashing time of LEDs.
Any help is appreciated.