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FDC2114: use of multiple FDC22114 on the single I2C of microcontroller

Vikas kumar Verma94
Prodigy 140 points
Part Number: FDC2114
Other Parts Discussed in Thread: FDC2214, LDC1314

Hi !

Is it possible to use multiple FDC22114 on the single I2C of micro controller for 50 Nos of capacitive touch in following configuration,

1. In 1:1 channel and touch key configuration where on one channel is representing one key, like in this case FDC22114 is having four touch channels, therefore we can have maximum four keys in 1:1 proposition 

2. In Matrix touch channel configuration, ie let us say 8X8 matrix which will use required only two numbers of FDC2214 on each side row and column, therefore total 4 FDC2214 will be required for 64 keys.   

Note: ( as there are only two hardware address per FDC2214 that is 0X2A and 0X2B, and I think we cannot change them dynamically by switching Address pin IO high/low to address in multiplexed format)

Please advice ! 

Thanks and Best Regards,

VK 

  • 0
    TI__Genius 13335 points

    Hello Vikas,
    We would recommend to use an I2C multiplexer for communication to the different FDC devices. We have test before the ability to dynamically change the I2C address pin and it does seem to work, but this is not documented in the datasheet so it is not a feature that is guaranteed.

    For the matrix question, we have in the past use a single LDC1314 and multiplexed its inputs in a 4x4 matrix to achieve 16 buttons. You can take a look at the reference design which has the details: www.ti.com/.../TIDA-00509

    Regards,
    Luke