I2C on XA1110: Firmware and Datasheet Versions

We had a bit of a scare on a project where we are laying out a board that uses the XA1110. We were working with the link on digikey for part XA1110_1104308. The datasheet there is rev1, according to which the I2C is diabled. A newer version (rev5) of the datasheet on the sierra site does not say I2C is disabled, so we assume as long as we source up-to-date hardware, we can be sure I2C will work. Is the part sold on digikey up-to-date with functioning I2C or do we need to source elsewhere? We do not want to have to re-flash each unit with new firmware to enable the feature.


So the hardware for the XA1110 is the same across the board it is just the software configuration that it comes in that changes across the SKU’s, so just make sure you order the right one. I think the one you are after will be as follows:

1104306 XA1110,GENERIC,GNSS,AXN5.1.6,GNSS=AB,UART+I2C; 9600 BAUD

4308 is UART+SPI.



Hello Matt,

Could you please provide some guidance where you found this information? I am in the same situation as kawasumilui and I would like to be sure to order the right one.

On DigiKey, you can find XA1110_1104308 or XA1110_1103891.

I didn’t find any reference to SKU or ID marking in the official docs to such suffixes. How to distinguish the one which is I2C+UART then?

From your original message, it sounds it is a matter of software. Does it means XA1110-1104308 is also I2C capable, BUT you need first to connect with the component to a PC using UART (through UART<->USB cable for example) to switch SPI to I2C in the config of it? what about XA1110-1103891?



I am a Sierra employee and hence have access to the catalog. All of our SKU’s start 110 (I guess until we get past 9999), the deifinition is only shared with partners and you really need to ask them. The Digikey site does not have enough detail to give the full description so you need to go to one of our more specialised disti’s (Digikey is great for getting hold of product globally really quickly) for this fuller description, its not something we do on the forums. I did it as a one off.



Hi Matt,

Thanks for this prompt answer!

To be transparent i asked digikey as I am looking for short quantities (~20 units for a first batch) with fast availabilities… but they didn’t answer up to now, so I was wondering who could have this kind of information.

Farnell element 14 (who is identified as premier partner in your distributor list when selected EMEA gnss solution) sounds not distributing it at all.

It is a pity that this part of information is not accessible through an application note for example, it will ease hobbyist life for sure :wink:


If I can share my experience, there is some sku# explained right here on the sierra site.
https://source.sierrawireless.com/resources/airprime/software/firmware-xa1110-dev-kit/#sthash.suKvo9wc.dpbs. you can also download the preferred firmware right there

in my experience, re-flashing the the unit is actually much easier than it at first seemed. Make sure you have access the the RX and TX pins on the sierra, connect a usb serial 232 adapter to those pins on a PC, and use SW GNSS Tool to reflash the firmware. (This is a bit from memory). So for 20 units, which is similar to what I needed fast, i’d just go with the re-flash route. For large production quantities is when you’d need to talk to sierra directly or their specialized distributors.

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@chiptronik31, @kawasumilui

The catalog is not the clearest document because you can easily misinterpret what it says as there are so many settings the different units we have can be set to (on the surface it might seem simple). So unfortunately an apps note would not really help, sorry.

As has bee said though there are bits and pieces detailing them for some of the products.



Thanks a lot @kawasumilui!

Basically if I capture it well, I just need to buy the same ref as you XA1110_1104308, and reflash it to make it work.
Did you use a true RS232 port or a virtual com port through a more classical usb to uart one?

as I have already a usb uart transceiver on my design, it sounds I just have to add jumper to redirect temporally the ports to gnss instead of the main microcontroller.

Any further guidance to confirm that one will be highly appreciated!

Thanks again to have shared your experience, it is really helpful!


I could imagine there are good reasons behind it… But indeed a note to explain where to start such as the experience explained by kawasumilui might help.

Or perhaps just a comment to inform that i2c support requests either specific sku sourcing or firmware flash…

Anyway at least there is this post now, which is always better than being “alone in the dark” :wink:


It seems that the firmware is no longer there. If I search source.sierrawireless.com for XA1110 firmware I end up on a page that lists the CP210x USB drivers and a couple of ‘download agents’.