J

jimevison

Member
I plan on using this puck with a Skyview. The EFIS wants a 38,400 Baud rate yet the default rate on the 18X 5Hz is 19,200. Garmin has a configuration program which will change the Baud rate on the puck connected to a Serial port. Com ports are not so common and I don't have access to one. Does anyone know if the Skyview has the ability to change Baud rate of a GPS on the serial port. It appears to me that the chipset in the Garmin 18x 5Hz is the same as that in the Dynon SV-GPS-250 given their like specifications.

Jim
 
jimevison said:
Does anyone know if the Skyview has the ability to change Baud rate of a GPS on the serial port.

Jim
Click to expand...

Jim,

I use the Dynon SV-GPS-250 and it just works so I have no first-hand experience changing the GPS baudrate in my Dynon Skyview. However, I'm quite certain what you're asking is provided for in the Skyview firmware.

Note that you won't "change Baud rate of a GPS on the serial port". The baudrate being changed is the Skyview's serial port used to communicate with the GPS, not the baudrate of the GPS. I assume the latter is what you're asking as the former is not really feasible.

The Skyview Installation Guide addresses this on page 4-14 (in my Rev. F copy). You can download that document from Dynon's web site; let me know if you need a link to it.
 
Joe said:
Jim,

I use the Dynon SV-GPS-250 and it just works so I have no first-hand experience changing the GPS baudrate in my Dynon Skyview. However, I'm quite certain what you're asking is provided for in the Skyview firmware.

Note that you won't "change Baud rate of a GPS on the serial port". The baudrate being changed is the Skyview's serial port used to communicate with the GPS, not the baudrate of the GPS. I assume the latter is what you're asking as the former is not really feasible.

The Skyview Installation Guide addresses this on page 4-14 (in my Rev. F copy). You can download that document from Dynon's web site; let me know if you need a link to it.
Click to expand...

You're right, I can match the Skyview Baud rate to that of the 18X 5Hz but it would not be optimized. Ideally I'd like to have them communicate at the fastest available speed of 38,400. The GPS has a fast update rate of 5Hz and I'd like to take full advantage of its capability.

Jim
 
Just because it has a 5hz update rate does not necessarily mean that it spits out all of the required NMEA sentences at 5hz.

My Aera is a 5hz GPS and it only updates NMEA every 2 seconds....

Hook it up to a computer and log the stream to be sure.

The higher baud rate may not help you any if the NMEA update is slow.
 
Jim,
I don't have an answer to your question about the Skyview. However, I did have to re-configure my GPS-18's baud rate and was eventually successful using Garmin's interface. I happened to have an old computer with a serial port at the time. I don't know what I would do now. I really miss good old RS232 ports. I hope the EFIS manufacturers take note of this and provide a means to do this.

Are you sure 19.2K baud isn't fast enough? Assuming 10 bits per character (including start, stop and parity), you would get 1920 characters per second. At a 5 Hz refresh rate you would have bandwidth for approximately 384 characters per refresh. I don't know how many characters are needed for a refresh, but I wouldn't think you would need anywhere near 384.

Anyway, just a thought in case you can't find a way to re-config the -18.
 
I programmed my GPS 18X by using a USB/RS232 cable. Plug the USB end in the PC and patch the GPS to the RS232 end. It's easy enough to quickly put together a patch cable so you can connect the Tx, Rx and ground wires from the GPS to the RS232 end of the USB cable. You then need to find a 5VDC power source for the GPS. I had an old USB cable and just cut off the end connector to expose the pigtail and used the USB port on the PC to provide the power.

You can then download the Garmin software to read and change the config file. A 30 minute job.
 
apatti said:
Are you sure 19.2K baud isn't fast enough? Assuming 10 bits per character (including start, stop and parity), you would get 1920 characters per second. At a 5 Hz refresh rate you would have bandwidth for approximately 384 characters per refresh. I don't know how many characters are needed for a refresh, but I wouldn't think you would need anywhere near 384.
Click to expand...

My Aera with the NMEA Advanced setting set to "Normal" spits out 854 bytes per update every 2 seconds. On "Fast" the amount of data is smaller and it updates every 1 second. The Dynon systems require a sentence that is left out when on "Fast" so I use "Normal".
 
Brantel said:
My Aera with the NMEA Advanced setting set to "Normal" spits out 854 bytes per update every 2 seconds. On "Fast" the amount of data is smaller and it updates every 1 second. The Dynon systems require a sentence that is left out when on "Fast" so I use "Normal".
Click to expand...

If this is the case, then 38.4K isn't fast enough either for a true 5Hz refresh rate. You would need 4270 bytes (5 X 854). So, the minimum would be 42.7K baud. What is the next standard rate? 56K?
 
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