I ordered two mt3329's one is sending out ascii from boot up and connects directly to minigps and gets good lock from inside the house.
The other one....on the same power supply never gets a lock and spits out what looks to be binary but I cannot figure out what exactly it is and it wont connect to minigps.
Is there some procedure I should follow to test the unit that is acting weird? Thanks
Here is what the weird unit is sending out
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Replies
Another user reported that the MediaTek uses the 3D fix output as an input at power up. It sets something but I've forgotten what. Maybe a search...
The way the adapter boards are wired seem to be in the less-stable mode. If it is as you describe, it is better to use the 3D output as a pull up rather than a pull down. (Which would reverse the sense of the LED vs the documentation.)
I think that you will find that when the unit is sending garbage, it is also failing to lock on to satellites, and the LED is blinking slower than normal. Instead of about 0.5 to 0.75 seconds on then 0.5 to 0.75 seconds off, it will be closer to 1 second on then 1 second off. (1/2 Hz)
The unit is also more sensitive to this odd mode if Vcc is a bit low. DIYDrones adapters seem to sag down to 3.1 V or so and have issues. (Do a search here.) Make sure the power supply is capable of keeping the Vcc pin 3.3 to 3.5V, and if you can, reverse the sense of the LED so that the unit powers up with the 3D fix pin low.