A while ago I bought this board http://www.seeedstudio.com/depot/LoNet-808-Mini-GSMGPRS-GPS-Breakout-p-2493.html and I am now trying to use it connected to a usb port on my laptop through a usb serial adapter.
- BAT to a 3.8V power supply
- RX and TX to my TTL pins
- VIO to the +5v from the adapter
- GND to a ground common to my power supply and my ttl adapter
All seems good, yet when I press the power button on the board, it powers on (green led lights up), stays on for a couple of seconds (green led stays up while red led blinks) and then shuts down (both leds shut).
During the process, I get nothing on the serial interface.
I feel like I’m missing something important here but I have no idea why. I’d appreciate any lead, even the obvious ones as I’m a complete beginner.
edit : resized picture
edit2 : Nevermind : my voltmeter is actually pretty inaccurate.