Code can't be uploaded to uno after attaching GSM SIM 900 shield to it.

Projects Networking, Protocols, and Devices
1

Hello everyone. I have purchased a GSM SIM 900 shield for my telecommunication project. The problem is: I tried to upload a code onto my Arduino UNO that asks user for a number send sms to the number.(The code is easy. You can find it in the arduino's File>exampe>GSM>SendSMS). Previously everything was fine, codes can be easily upoaded and executed from the board. But after connecting the GSM shield, code can't be uploaded anymore. Anytime I press the upload icon, it starts upoading but gets stuck at middle showing this error messages:

avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x00
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x00

Can anyone please explain what's happening and how to get rid of this problem? Thanks in advance. :slight_smile:

2

As a pure guess you have the SIM900 shield configured to use D0 & D1, which are the same pins used to upload your code to the Arduino?

Incidentally, the examples provided with the IDE are intended for use with the official Arduino GSM/GPRS shield, which utilises the Quectel M10 chip, not the SIM900.

See here