Few days ago I purchased this GSM/GPRS shield (http://www.geeetech.com/wiki/index.php/Arduino_GPRS_Shield). Shield works fine, i was able to send SMS and make voice calls, but the problem is network connection, on some random locations shield will not connect to a network (Croatia, T-Mobile).
Now I'm thinking to update firmware, and I found nice tutorial here GeekOnfire.com is for sale | HugeDomains but as said, to update firmware one of the requirement is: "Any FT232 device or an Arduino with FT232 chip (new UNO and Mega will NOT work because they use Atmega8U2/Atmega16U2)".
I own Arduino Uno R3 so that one will not work but I also own USBtoSerial FT232 Adapter (bit.ly/10LcSeh).
How to connect that USBToSerial FT232 module with the shield and update the SIM900 firmware? This could be a noob question but I don't want to burn my shield or something...
You just need to connect the RX from the FTDI interface to Sim900 TX, TX from the FTDI to the SIM900 RX and the grounds between them .
If you wire it wrong you wont be able to start the process
SOLVED!!
Update successful!
OK, just like Hugo told, connecting TX with RX, RX with TX and GND with GND on the shield. I also had to lower the baudrate to 115200, set the jumpers, powered the shield and I didnt keep pressing ON/OFF button, I just hold it for a few seconds and it started updating the firmware.
I can also confirm that now shield is connected to a network so that problem is also solved.
My gsm board has revision:1137B12SIM900M64_ST. As it seems, it's the latest release. Anyway, since I have no better idea, I desided to refresh firmware. But I am getting "error during baud rate change". I tried all possible baud rates; gsm shield was set to 115200.
I had the same issue where no baudrate would work with the update following this tutorial:
It turns out that they had one instruction wrong. Instead of rapidly pushing the power button, you must HOLD IT until you get the "Flash loader downloaded in ram" message. After I held the powerkey button instead or just pressing it multiple times, the upload process worked flawlessly. (I think when they said "KEEP pressing the power button", they meant to hold it, not to repeatedly press it.)
It's too bad that the tutorial doesn't have contact information pinned to it. Otherwise I would contact them to update the tutorial and make this more clear. For now I will just leave this plug here.
Hope this helps.
I'm struggling with this too. I have a FTDI USB to Serial adapter, and i'm pretty sure the thing works ok.
I have Rx to Tx and Tx to Rx, power is ok . tried all different baud modes, nothings works, the simcom updater
stays at 'please power up the target'; There's no way to get it past this. I tried to hold the power button in every
possible way (even for 5 minutes) , no luck The Tx light on the FTDI board keeps flashing as soon as i hit 'start' in simcom.
Obviously the module doesn't reset in a good way so that the flash loader can't be send, that's what i think;;
I'm out of answers to myself anymore, i think i should get an arduino mega or duemilanove but i can't get one
pretty fast over here
The Tx light on the FTDI board keeps flashing as soon as i hit 'start' in simcom.