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Tips and questions relating to the GPS modules from SFE
By theridane

I've been having issues with the Locosys 20031 GPS module. When powering up (attaching the 3V3 line to the module), the LED flashes briefly and within seconds the module gets a fix and starts transmitting updates. Average draw is 30 mA.

When I try powering it up with the TX pin grounded (or connected to an MCU), the draw is closer to 50 mA, and the LED stays on. The module is sinking close to 20 mA through the TX-GND line. It stays in this state indefinitely.

When I start the module up with just the 3V3 and GND lines plugged and THEN attach the TX-GND line, the module immediately pushes valid serial data into it. The issue manifests itself only when the module is being powered on.

Could it be because the LM2576T-3.3 produces noisy power?