Google's latest additions to the Nexus family, the Nexus 4 and 10, have introduced a host of changes to Android, both in terms of software and hardware. These changes include the physical NFC controller used in the devices, as well as the default NFC stack used in AOSP (Android Open Source Project - essentially 'stock' Android). A consequence of these changes is that both of these new devices will not support the use of the incredibly popular Mifare Classic class of NFC tags.
In a review conducted by Anandtech, it was found that the Nexus 4 makes use of the Broadcom BCM20793 NFC controller. All previous NFC-enabled Nexus devices (Nexus S, Galaxy Nexus, Nexus Q and Nexus 7), as well as the vast majority of non-Nexus Android phones, have made use of NXP's PN544 controller.
In addition to this hardware change, Google's Android 4.2 changelog for developers mentions the addition of a new NFC stack with wider physical NFC controller support, jointly developed with Broadcom.
The above changes mean that Google's latest Nexus devices will not be able to read or write to Mifare Classic NFC tags. Mifare Classic tags make use of proprietary protocols developed by NXP; they are not NFC Forum compliant. As a result, phones with non-NXP NFC controllers are unable to communicate with the tags.
This incompatibility might cause trouble for some users, as Mifare Classic tags remain incredibly popular, mainly due to their low price. For example, Samsung's TecTiles tags are rebranded Mifare Classic tags, as are the majority of generic tags available online. Many schools, universities and businesses issue Mifare Classic cards for building access, ticketing and business cards.
However, it should be noted that NFC Forum Type 1-4 tags are also readily available for online purchase. Tags of this type will function with the Nexus 4 and 10, as well as future Nexus devices. Tags of this type include Topaz, Mifare Ultralight C, Mifare S50 and the UPM Ntag. Nexus owners seeking to make use of blank NFC tags for automation should endeavour to look for the above tag types.
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