I was using A7 module to transmit data to thingspeak and it was working fine. But for some reason, it stopped working and I have been trying to debug it for days now. It isn't accepting normal AT commands also. When I type AT in the serial window, I get no response.
My connections are -
Rx---->0 of Arduino Mega
TX---->1 of Arduino Mega
GND common
and I am powering GSM module by USB cable. The serial monitor is at Both NL & CR and at a baud rate of 9600. Please Help
Why would you connect something to the RX and TX pins, removing your ability to debug your program? You have 3 other ports that you could connect the device to. Use one of the other ones.
Post a schematic. You only mentioned 2 of the 4 required connections.
PaulS:
Why would you connect something to the RX and TX pins, removing your ability to debug your program? You have 3 other ports that you could connect the device to. Use one of the other ones.
Post a schematic. You only mentioned 2 of the 4 required connections.
Even if I use the other three RX and TX port it doesn't give me back a reply. The other connection is a common ground. I am just debugging it so I have uploaded a blank code and using serial monitor , I am sending AT command. What are the remaining two connections ?
Which breakout board are you using for the A7 ? The basic module has this voltage specification taken from "A6/A7/A6C User Manual":
Working voltage : 3.3V-4.2V;
Power voltage: >3.4V;
Standby currents below 3ma, A7 increase 2m;
Support quad-band GSM/GPRS,include 850,900,1800,1900MHZ;
GPRS Class 10;
Sensitivity: <-105;
Supports voice calls
Supports SMS messages
GPIO-level 2.8V;
The device could have simply failed.
It could also be that due to some external factor such as a SIM card credit running out, Thingspeak account problem etc., you noticed a problem which you are now investigating, and there is an error with your test method. Having said that, there is not much that you can do wrong if you are connecting to the correct serial interface on the A7 of which there are 3, vou've understood the common ground issue, you have the right baud rate and have understood that you cross over TX and RX when talking to a serial device.