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FDC1004QEVM: FDC1004

Güney Can
Prodigy 20 points
Part Number: FDC1004QEVM

Hello,

I have a question. If I read the register via i2c with Raspberry Pi 4, than I get the Information

        0   1   2   3   4   5   6   7   8   9   a   b   c   d   e   f                0123456789abcdef
00: 03 20 02 19 01 31 01 85 10 3c 5c 7c 0d 00 00 00               ? ???1???<\|?...
10: 00 40 40 40 40 XX XX XX XX XX XX XX XX XX XX XX      .@@@@XXXXXXXXXXX
20: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XXXXXXXXXXXXXXXX
30: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XXXXXXXXXXXXXXXX
40: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XXXXXXXXXXXXXXXX
50: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XXXXXXXXXXXXXXXX
60: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XXXXXXXXXXXXXXXX
70: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XXXXXXXXXXXXXXXX
80: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XXXXXXXXXXXXXXXX
90: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XXXXXXXXXXXXXXXX
a0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XXXXXXXXXXXXXXXX
b0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XXXXXXXXXXXXXXXX
c0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XXXXXXXXXXXXXXXX
d0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XXXXXXXXXXXXXXXX
e0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XXXXXXXXXXXXXXXX
f0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX 54 10 XXXXXXXXXXXXXXT?

for example in the address 0xff is written the device ID. But the device ID has 0x1004 . Where is the information 04? how can I get it? also for the value of channel 1 staying 03 (address 0x00) and 20 (in address 0x01). If I get the information via comport, than I get 3 bytes and not 2 bytes. If I compare, than is the first byte exact the same, but the second byte has a differently value. Can you explain me?

best regards 

Güney Can

  • 0
    TI__Mastermind 43730 points

    Hello Guney,

    We are not the experts in Raspberry Pi, so I don't have feedback on the data you see from the Pi.  I did take a logic analyzer shot of reading the device ID register(0xFF), which should be useful for your debugging.  I recommend getting a shot of your communication with the Pi and looking for differences.  If you have questions or would like me to also review your I2C capture, please post it here.    

  • 0 in reply to Eddie LaCost
    Prodigy 20 points

    Hello Eddie,

    thank you for your answer. It's possible that you misunderstood me. My question was, are the information over capacity in the channel1 to channel4 2 Bytes or 3 bytes? The reading via i2c was not a problem for me. I can change also the values if register is R/W. The problem what I have to understand, why the program "Sensing Solutions EVM GUI" gives me 3 bytes information over the capacity and i2c only 2 bytes. 

    best regards

    Güney Can

  • +1 in reply to Eddie LaCost
    Prodigy 20 points

    Ok I find out that the value information of channel are always 2 bytes. You must shift this information to 3 bytes. For example if you have 0x03 and 0x45 than is the complete information 0x034500. The last byte is always 0x00. And this value you must divider with 2^19. The result ist the capacity in pF.