FAQ 3G poweron

Ques) LED D2 on the cape is not glowing after powering up the Beaglebone black plus cape setup?

Ans)1) Ensure setup was powered up initially using a DC adapter (5V, 2.5A min) only.

2) Ensure the power jumper (#12 on leaflet) is present.

Ques) Can the BBB plus Cape setup be powered up using USB cable too?

Ans) USB cable alone cannot provide sufficient power(only500mA max) to drive the Beaglebone Black and Cape together, so it is possible that BBB will not boot properly and the Modem may not even power up.

Use a DC power adapter of 2.5A,5V rating at barrel jack to properly boot Beaglebone black with our cape.

Connect USB cable for SSH login purposes only.

Ques) Modem is not visible in the list of devices after issuing “lsusb” command on the Debian wheezy shell?

Ans) Beaglebone Black USB host port has a bug when used with external USB hubs.

1) After powering up the BBB plus cape setup, ensure modem was turned on by either using the switch S1 or controlling GPIO 45.

2) Then a USB cable has to be connected between USB host port on BBB and mini-USB device port on the cape. Now issuing a “lsusb” command should show Modem (21f5:2012) among list of devices.

3) Also ensure that GPIO45 and GPIO60 are set high in output mode after BBB boots up.

Note : If you face issues detecting Modem after following above steps, then alternately connect USB cable between BBB and Cape before power up and attach a USB device(pendrive etc) to the extra USB host port available on the cape. Then, Power up the BBB plus cape setup and after proper bootup, turn on the Modem.

Ques) Modem is visible in list of devices shown by “lsusb” but no “ttyUSB” ports are created?

Ans) 1) Make sure you are logged in as root.

2)Ensure the Debian Wheezy or the OS used has drivers installed for the modem. Pre-compiled Images with drivers included are available on Yantrr Wiki page.

3) Alternately, issue the following command to initialize drivers for the Modem ports.

	sudo modprobe usbserial vendor=0x21f5 product=0x2012

Note : This will create generic ports for the Modem, but it is advised to include drivers in the kernel.

Ques) How to issue AT commands to the modem?

Ans) Both ttyUSB0 and ttyUSB2 take the AT commands, but ttyUSB0 port is also a Data communications port so for all intended purposes of issuing AT commands use ttyUSB2 port(PCUI port).

Ques) What are some common useful AT commands to ensure 3G modem is working?

Ans) Some common AT commnds :

1) AT = Output “OK” if modem is on.

2) AT+CPIN? = Outputs the status whether sim card is detected or not.

3) AT+CREG? = To check if sim card is registered or not.

4) AT+COPS? = Operator selection.

5) AT+CSQ = Outputs Signal strength.

For more information and full set of information use : WCDMA AT Commands Manual

Ques) What is the function of each LED? What do they denote and how do they function under different conditions?

Ans) D2 is power Led of Cape, which denotes the 5V power being provided to Cape and for the Modem.

D7 is 3.3V power LED from the Beaglebone Black. This denotes 3.3V power for GPS module and other ICs on Cape.

D5 is 1 PPS Fix led for the GPS module. It will blink at the rate of 1Hz, when GPS module has got its fix.

D4 is Netlight/Signal Led for the 2G/3G Modem. It has different behaviours depending on the state of Modem. For 3G modems, it is an optional feature. Ask for this feature while ordering.

D3 is Status LED for the GPRS Modem. It gives the indication whether the GPRS Modem is on or not. It glows continuously when the Modem is Turned ON and stays off when the Modem is turned OFF.

Ques) What are the functions of the different Switches?

Ans) S1 is ON/OFF push button switch for the Modem.

S2 is Hard Reset push Button switch for the Modem.

S3 is Reset push button switch for the GPS module.

S4 is 2 position DIP switch for specifying address for the EEPROM IC of cape on I2C2 bus of Beaglebone Black.