[SOLVED] SIM900A responding with ERROR

[Mrunal Ahirrao]

Hi,
I am working with SIM900A GSM module. I was testing it by sending ""AT\r\n" but it is responding by string ERROR. I am using PIC18F452. The same code was working well with SIM300 but SIM900A is responding with ERROR. And when used with PC it is working correctly it is giving correct OK response on PC but not with MCU. I have tried extracting large data also from SIM300 with success but SIM900A seems some what different, but AT commands are same at least basic. Any help would be appreciated.

 

[prakashvenugopal]

Hi,

For SIM900, the delay have to be increased.

Regards,
V. Prakash

 

[Mrunal Ahirrao]

Hi,

Can't use normal software delay as it will cause overrun errors. So need to make delay using internal timer it seems, isn't it?

 

[pic.programmer]

Hi

What is the baudrate you are using for SIM900A ?

If MCU code uses 9200 bps baudrate then connect SIM900A to PC and issue AT+IPR=9600\r once so that baudrate is set properly.

 

[Mrunal Ahirrao]

Hi

What is the baudrate you are using for SIM900A ?

If MCU code uses 9200 bps baudrate then connect SIM900A to PC and issue AT+IPR=9600\r once so that baudrate is set properly.

Hi,

I am using 9600 baud.

 

[Mrunal Ahirrao]

SIM900 is slow in responding than SIM300, so I used delays as V.Prakash suggested. Thank you prakash.