I'm surprised an Adafruit shield wouldn't do that. Any well designed shield will use those pins rather than assuming I2C is on A4 and A5. That way, the I2C bus is broken out to a standard location, which allows shields that use I2C communication to work on all boards. This is why Arduino added the SDA and SCL pins in the R3 pinout. You will find a similar situation on the Mega and Leonardo, which also don't have I2C on A4 and A5. That was not possible on the original Uno because it has less IO.
The thing is that by not having I2C on A4 and A5 you are gaining another two IO pins on the Uno WiFi Rev2. I fully understand that these two boards are very different internallyĬorrect. This may have something to do with the WiFi chip and inertial chip being on the board. In this image, the green and red highlights indicate the working (green) and non-working (red) SDA and SCL pins on the WiFi Rev2 with the above mentioned display combination. If anyone knows of a pin-out diagram specific to the WiFi Rev2 or some other documentation that explains this difference, it would be appreciated. I fully understand that these two boards are very different internally, but thought the pin-outs were the same. I couldn't find a pinout diagram for the WiFo Rev2 and so far have not found any technical documentation referring to this difference. On the REV2 the combination does work if the alternate SDA and SCL pins are used (the ones near the AREF pin). It works fine if that display and backpack are installed on an UNO on those same pins. Specifically, on the WiFi Rev2, I installed an Adafruit LCD 16x2 display with Adafruit I2C backpack on pins A4 (SDA) and A5 (SCL) and spent substantial time trying to get it to work but it never did. Not all MKRs are designed to have wireless connectivity though, as the Arduino MKR Zero is better used as a great educational tool for learning about 32-bit application development.I have discovered that the pin-outs for SDA SCL appear to have some differences on these two boards. Do note that as of the time of this writing, that this MKR has services in Europe only. It comes with a free 2-year subscription, with up to 140 messages a day. The Arduino MKR FOX 1200 gives the MKR the capabilities to connect to a SigFox network with their low-power data sharing capabilities. The Arduino MKR GSM 1400 provides the popular SARAU201 GSM module to add this MKR global GSM connectivity.įor Lo-Ra WAN connectivity, the Arduino MKR WAN 1300 will be your board, with its added Murata CMWX1ZZABZ Lo-Ra module. The Arduino MKR1000 is meant to connect to Wi-Fi, specifically using its WINC1500 low-power 2.4 GHz IEEE 802.11 b/g/n Wi-Fi at 72 Mbps. With its design tailored to IoT development, the MKR series has a variety of ways to connect wirelessly. Wireless connectivity is the strong point of the MKR series. While they are not compatible with Arduino Uno Shields, you can plug in your MKR into the MKR2UNO, where it allows you to turn your Arduino Uno Shields into a MKR based one, so this is great for people that have existing Uno Shields (though note that not ALL Shields are compatible)!Īs of right now, there are a few MKR “Shields” where you can plug in your MKR, like the MKR Relay Proto Shield that gives you the ability to work with relays and also provides space to add other components to your project with its small prototyping area. They also include 7 analog input pins and 1 analog output pin. They come with a total of 22 digital I/O pins with 12 being PWM pins. The MKR series have the same number of I/Os across all their boards. There are hundreds of Shields that can be used on the Uno R3, ranging from a Relay Shield, a Motion Shield, and even unique Shields like Integreight’s 1Sheeld+ for iOS and Android.
The Uno R3 doesn’t come with wireless connectivity right out of the box, but you can add a Wi-Fi Shield to get this feature. It comes with 14 digital I/O pins (with 6 of them having PWM) and 6 analog input pins. We’ll start off with the easiest and most familiar board, the Uno R3.
This is where you’ll see the biggest differences between all the boards. View Arduino Board Connectivity Comparison Arduino MKR1000 WiFi (with headers) | ABX00011