PPS signal measure, GPS GTPA013

[gambox]

Hi, I have some problem with the PPS signal of the GTPA013. I power on the device and I put in the PPS output Oscilloscope tip but I can see nothing. I expected to see a square wave o pulse witdh with 50ms of duration. Is necessary to configure PPS output with at command?

[adafruit_support_mike]

You shouldn't need to configure the PPS output.

Where do you have your probe's ground strap connected?

[tastewar]

Does it need a fix before it can provide the PPS output?

[gambox]

You shouldn't need to configure the PPS output.

Where do you have your probe's ground strap connected?

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I put the probe's strap in GND of power supply and the meter point in the output PPS's signal pin.

[adafruit_support_mike]

I'm a bit leery of breakboard connections, so check the signal at the solder joint on the PPS pin. It's also a good idea to make the GND connection as close to the signal you're measuring as possible.

The module does need to get a fix from three satellites before it starts generating PPS, so you might be seeing some latency there. Check the NMEA output to see how many sattelites the module is reporting.

[geogeo]

According to the manual it seems that 3D fix is needed (>=4 satellites) before generating PPS.

Could you clarify this :-) ?

Thanks in advance!

[adafruit_support_mike]

I'd go with what the manual says. IIRC, I wrote some simple test code with an interrupt handler watching the PPS pin and NMEA sentences coming in through the Serial Monitor. I had the impression that the PPS started when the system reported the third satellite, but that may have been incorrect.

If the number of satellites is critical to your application, go ahead and run your own tests. Nothing beats freshly collected data.