Re: [gpsd-users] Support for PPS on 10Hz Devices

[Andrew Yong]

Hi Anthony,

On 16 Sep, 2013, at 4:23 am, Anthony Stirk <address@hidden> wrote:

I might be out of turn here but isn't the PPS output still 1Hz regardless of the NMEA output frequency ?

Yep, the PPS still comes in at 1Hz, but for some reason GPSD doesn't pick it up.

I recall seeing a patch to the code base to specifically support the Garmin 5Hz LVC. 

Perhaps GPSD is overwhelmed with the 10Hz output, or just is expecting 1Hz NMEA?

I did noticed when using the Adafruit module it seems to fire PPS on both the rising and falling, i.e I was getting 2 pulse per second. Switched it for a ublox which seems to work better (by better I mean 1 pulse per second).

I'm seeing the same behavior here. I've actually dropped a few emails to GlobalTop, which makes the GPS module. 

I can customize the PPS pulse duration; it's set to 100ms by default. Should I get that decreased or increased for better compatibility with GPSD's PPS detection?

Anthony M0UPU

On Tue, Sep 10, 2013 at 12:07 PM, Andrew Yong <address@hidden> wrote:

Hi chaps,

I have a 10Hz GPS module with 10Hz NMEA sentences, and PPS doesn't seem to be picked up. Has anyone tried this?

I only see workarounds for 5Hz GPS in the code.

My module is an Adafruit Ultimate GPS Breakout (GlobalTop module, MTK3339 chip), through a FT231x with PPS on DCD pin.

Cheers

Andrew Yong

Yours

Andrew Yong

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