Hello,
I needed to work with GSM so I bought a SIM908c module. Also I bought a breakout board to connect with Arduino Mega. I am using the gsmlib library for this module.
My connections are as follows:
3.5V 1A power input + 100uF bypass capacitor => VBAT
3.5V 1A power input + 4.7uF bypass capacitor => VRTC
Power Adapter ground => GND
Arduino Mega pin 53 => PWRKEY
Arduino serial TX1 pin 18 => TXD
Arduino serial RX1 pin 19 => RXD
Power Adapter ground => DTR
Now I am using the library example of AT command named GSM_GPRSLibrary_AT. After uploading the sketch and observing the serial monitor the following responses show up:
GSM Shield testing.
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:ELSE
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:ELSE
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:ELSE
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:AUTO BAUD RATE
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:NO BR
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:NO BR
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:NO BR
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:NO BR
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:NO BR
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:NO BR
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:NO BR
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:NO BR
Trying to force the baud-rate to 9600
1200
ATT: OK
RIC: AT+IPR=9600
AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
2400
ATT: OK
RIC: AT+IPR=9600
AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
4800
ATT: OK
RIC: AT+IPR=9600
AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
9600
ATT: OK
RIC: AT+IPR=9600
AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
19200
ATT: OK
RIC: AT+IPR=9600
AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
38400
ATT: OK
RIC: AT+IPR=9600
AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
57600
ATT: OK
RIC: AT+IPR=9600
AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
115200
ATT: OK
RIC: AT+IPR=9600
AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ERROR: SIM900 doesn't answer. Check power and serial pins in GSM.cpp
status=IDLE
This kind of responses appears even if I don't give any power to VBAT and VRTC. I am definitely did something wrong but I can't figure it out. Please kindly help.
I needed to work with GSM so I bought a SIM908c module. Also I bought a breakout board to connect with Arduino Mega. I am using the gsmlib library for this module.
My connections are as follows:
3.5V 1A power input + 100uF bypass capacitor => VBAT
3.5V 1A power input + 4.7uF bypass capacitor => VRTC
Power Adapter ground => GND
Arduino Mega pin 53 => PWRKEY
Arduino serial TX1 pin 18 => TXD
Arduino serial RX1 pin 19 => RXD
Power Adapter ground => DTR
Now I am using the library example of AT command named GSM_GPRSLibrary_AT. After uploading the sketch and observing the serial monitor the following responses show up:
GSM Shield testing.
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:ELSE
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:ELSE
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:ELSE
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:AUTO BAUD RATE
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:NO BR
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:NO BR
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:NO BR
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:NO BR
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:NO BR
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:NO BR
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:NO BR
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
DB:NO BR
Trying to force the baud-rate to 9600
1200
ATT: OK
RIC: AT+IPR=9600
AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
2400
ATT: OK
RIC: AT+IPR=9600
AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
4800
ATT: OK
RIC: AT+IPR=9600
AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
9600
ATT: OK
RIC: AT+IPR=9600
AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
19200
ATT: OK
RIC: AT+IPR=9600
AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
38400
ATT: OK
RIC: AT+IPR=9600
AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
57600
ATT: OK
RIC: AT+IPR=9600
AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
115200
ATT: OK
RIC: AT+IPR=9600
AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ATT: OK
RIC: AT
ERROR: SIM900 doesn't answer. Check power and serial pins in GSM.cpp
status=IDLE
This kind of responses appears even if I don't give any power to VBAT and VRTC. I am definitely did something wrong but I can't figure it out. Please kindly help.