Tamagotchi Friends Teardown

There’s a new Tamagotchi in town, so of course I had to get one (or two or three) and take it apart. The Tamagotchi Friends is the latest Tamagotchi version, which was released two days ago (December 16, 2013). It has similar functionality to previous Tamagotchis, but it also has NFC! The NFC functionality can be used to make Tamagotchis visit and give gifts, and can also be used to “SMS” other Tamagotchis. The Tamagotchi Friends does not have IR or use figures like previous Tamagotchis.

Introducing the latest Tamagotchi!

Overall, the look and feel of the Tamagotchi Friends is very similar to the TamaTown Tama-Go (which I have done most of my hacking on), the screen resolution and many of the screens are the same. There are a few differences though. There’s new characters, enhanced ‘social’ stats related to the NFC functionality, the ability to collect items and different foods and items. Also, in keeping with recent Tama parenting trends, there is no longer a way to discipline your Tamagotchi. That said, all the changes are superficial, and the vast majority of the Tamagotchi Friends and Tama-Go functionality is identical. This makes me strongly suspect the Tamagotchi Friends uses much of the same code as the Tama-Go, with some different images, and NFC functionality added.

Separated at birth?

Opening it up, the LCD looks very similar to the one used on the Tama-Go (likely the same exact part).

The PCB is quite different though. It is generally very sparse, and has a small number of components. The large IC is likely the EEPROM which is used to save the Tamagotchi state. On the left is the NFC antenna, which is attached using the red and black wires. What’s interesting is that the Tamagotchi Friends doesn’t seem to use any dedicated NFC component (at least which is visible). This means that the Tamagotchi microcontroller probably implements NFC directly.

PCB and NFC antenna

Taking off the LCD, the microcontroller blob is also interesting, in that it is much smaller than the blob on the Tama-Go. This makes me suspect there could be a different MCU. There’s also a strange feature at the left, where the epoxy appears to cover pads similar to the LCD pads.

This leads me to three theories:

1) It uses the same MCU as the Tama-Go, but it is laid out better, so it can fit under less epoxy
2) It uses a similar MCU to the Tama-Go, but a more modern version which is smaller
3) It uses a different MCU (with the sub theory that there could be multiple dies under the epoxy)

My guess is 1 or 2 (leaning towards 1, as I haven’t heard of any updated GP microcontrollers coming out). But who knows? I’ll be trying to get the chip decapped, as well as playing with the NFC to see if I can figure out more!