RPI HAT what interface for GNSS

[Miha90]

I need help! I am developing an open source GNSS HAT for the RPI4. I want to use the UBlox NEO 8. What interface should I be using in order for it to work nicely with OpenCPN? UART/USB/SPI/DDC are available from the data sheet.

[rgleason]

I would review the OpenCPN documentation for setting up Linux and RPI if I were you.
https://opencpn.org/wiki/dokuwiki/do...ps_setup#linux


https://opencpn.org/wiki/dokuwiki/do...spberrypi_rpi2


I have not set up RPI yet, so cannot be more specific. Others will help I am sure.

[Dsanduril]

For direct implementation with OpenCPN the easiest path is NMEA 0183, this is supported natively and directly by OpenCPN - no other decoding software widget would be required. O recognizes serial ports on the host directly - this is built-in functionality. On the NEO 8 NMEA is available on both the UART and USB interfaces:

UART
9600 baud, 8 bits, no parity bit, 1 stop bit.
Configured to transmit both NMEA and UBX protocols, but only the following NMEA (and no UBX) messages have been activated at start-up: GGA, GLL, GSA, GSV, RMC, VTG, TXT

USB
Configured to transmit both NMEA and UBX protocols, but only the following NMEA (and no UBX) messages have been activated at start-up: GGA, GLL, GSA, GSV, RMC, VTG, TXT
USB power mode: bus-powered

On Linux OpenCPN should be able to access either port with built-in drivers, not much difference and not much configuration required, so whichever is easier to implement in the hat.

If, for some reason, you want to use SPI/DDC you could use the OpenPlotter installation to add some I2C support or write your own code, but that is a more difficult path for the stated purpose of integration with O (but there may be other reasons depending on alternate uses for your project).

[rgleason]

Dsanduril
Thanks, added it to the RPI Install page
https://opencpn.org/wiki/dokuwiki/do..._hat_gps_setup


Hope it is ok.