Using UART on the Nova with a Raspberry Pi


#1

As anyone got the UART interface on the Nova working with a Raspberry Pi?

Can I just use the TX/RX pins on the Pi, or do I need to use RS-323?


#2

Hi just to clarify, you’d like to wire from the serial pins on the Pi to the serial pads on the Nova? One thing to note is that the logic level on the Nova’s pads needs to be 1.8V


#3

Thanks for the reply.
Yep, I know now I need a level shifter. The Ublox System integration manual has a good example off how to do this.

Ultimately, my question is, can I use use the AUX UART interface on the Nova instead of the USB interface to give my Pi access to the Internet


#4

Yes, this should be possible as long as a level shifter is in place. However, note the interfacing method will be different, since the SDK is built to work with the USB interface, so moving to the serial interface would require additional code (which I haven’t tried). If I was going to do what you’re doing, I’d be shifting to AT commands. However, it looks like you’re already looking at uBlox documentation, so you seem like you’re on the right path.


#5

it is a bit late, but here is the level shifter I used to get it working. From uBlox documentation

BTW: Chis, I’ve learnt a lot from your Kicad Tutorials… thanks!


#6

Awesome, great to hear!

I reworked the Nova schematic to work on my Beaglephone Pocket project, you can see the schematic of what i did here:

This was also the source of my mistakes on the 1.0, so be careful with pinout!


#7

Thanks great info and reference!.
At first, i used the same level shifting method you used… which worked. But i changed to the SN74AVC2T24546 as it takes up a lot less room.

this is what I have so far…still a big work in progress… got all working on a large board, now I am shrinking it all down for a Raspberry Pi Zero.

The USB (PCB) connector at the bottom will be removed once i finalize it.


#8

Yes, that part is muuuch smaller. But also about 10x the price of two tiny transistors with four tiny resistors. Cost vs space tradeoff, I suppose :slight_smile:


#9

That’s a cool looking design btw. Direct plug into USB? Also what is IC1?


#10

IC1 is a GPS Module from Antenova
The USB is only for testing as it is a bit fiddly, ill replace it with a micro USB connector later on.

I also have an Atmega328 on the under side.

At lot of the male pin headers will be removed once i finish testing.