I have an I2C device that I would like to interface with Android. It seems that the easiest way would be to use a microcontroller compatible with Accessory Development Kit. But these kits and their microcontrollers are huge in size and I am looking for a solution which will work with a micro-USB and will fit in a form factor of 1 x 0.5 x 0.5 inch.

FT311 seems to be another option but it looks like an overkill for my application.

Is there any other option that I can use. I was hoping for something small like TI's MSP430 to work with Android.

  • \$\begingroup\$ Appears to be a shopping question. Those are off-topic. \$\endgroup\$ – Brian Carlton Nov 20 '12 at 19:00
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    \$\begingroup\$ How is the FT311D overkill? You're going to be hard pressed to find a smaller, easier to use, or cheaper chip that has USB host functionality (as the Android interface requires) \$\endgroup\$ – Jim Paris Nov 20 '12 at 19:10

If you're looking for an off the shelf development board that is going to fit in an area of 1" x 0.5", it's not gonna to happen. Even the smallest MSP board I could find is 1.9" x 1.9", doesn't have USB or I2C functionality, and doesn't even have a power supply:

MSP Header board

If that form factor is a hard requirement, then the board will need to be custom. The ADK is open source. So just take the schematic files and do the layout yourself to fit within your desired form factor.

  • \$\begingroup\$ Thanks for the help.I was planning to do the layout myself in the long run. But I wanted to start off with the smallest uC that would be of use to me. Maybe the question should have been, which is the smallest uC that can to USB->I2C with Android \$\endgroup\$ – user16259 Nov 20 '12 at 20:56
  • \$\begingroup\$ @user16259 The ATMega32U4 has both USB and I2C with only 44 pins. In QFN package it's only 7mm a side. Since it's the same family it should be code compatible with the ADK. Although you have 1/8 the amount of memory to work with. \$\endgroup\$ – embedded.kyle Nov 20 '12 at 21:31
  • \$\begingroup\$ Notice that the bulk of the area of this board is given over to breaking out pins, the vast majority of which will not be used. As such it's not really a meaningful answer - there are plenty of development boards out there which are smaller, and it's unclear that the chip on this board even has the necessary USB functionality. \$\endgroup\$ – Chris Stratton Dec 21 '12 at 15:29
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    \$\begingroup\$ @embedded.kyle - careful, the 32U4 has a USB DEVICE interface, while the ADK has a USB host interface provided by an additional chip. Some Android devices can be USB hosts and thus talk to a device, but not using the ADK protocol which requires an external host. \$\endgroup\$ – Chris Stratton Dec 21 '12 at 15:32
  • \$\begingroup\$ @ChrisStratton You are completely correct in your statement. The OP makes no assertions as to the type of USB functionality needed and I merely attempted to state that the 32U4 was code compatible. Thank you for clarifying. \$\endgroup\$ – embedded.kyle Dec 21 '12 at 15:55

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