Problem setting capability container via IIC

[christiang_v_bø]

I'm using the NT3H2111 for a project. I can write and read data to/from the tag via IIC, without any problems.

I need to write some data, that an Adroid app will consider to be valid NDEF data. I cannot get that to work. Through tests and reading I have come to the conclusion, that the capability container has to contain correct values for the app to approve data as valid NDEF, so I'm trying to write data to the capability container.

The problem here is, that the IIC address is located in the same 16 bytes block (block 0) as the capability container, and no matter what I do, if I write to this block, the tag is no longer responding to any IIC commands.

The IIC address of the tag is 0x55 and I write 0x55 to byte 0 of block 0, which is the location of the IIC address in the tag. But I now have pile of non responding tags...

Does anyone have experince with or a solution for this problem?

[christiang_v_bø · Accepted solution]

I figured it out. The IIC address to write to the tag is not 0x55. It is a 7-bit address, but since bit 0 is the write/read indicator, the 7 bits are shifted one to the left, so the resulting address is 0xAA. When I write this to byte 0 of block 0, it works. So I can now change the capability container contents without any problems.