FDC2212: Why not to write the register 0x1E (DRIVE_CURRENT_CH0)

Dengkuan Sun

Part Number: FDC2212

Tool/software:

Hi Experter

I am using FDC2212 to design my system. Now, I met an issue about writing the register 0x1E (DRIVE_CURRENT_CH0). When I tried to write the value (0x8C40) into this register and read it, the read value is 0x8800. Also, I wrote other registers and read them, they are corrected. Can you explain this?

Thanks

5 months ago

0 Eddie LaCost 5 months ago

TI__Mastermind 44665 points

Hi Dengkuan,

The maximum value for the useable bits in this register is 0xF800. It looks like the reserved bits are being zeroed out, which would result in 0x8800 for your configuration. This should have no difference in the functionality of the device. See the register map below.

0 Dengkuan Sun 5 months ago in reply to Eddie LaCost

Prodigy 240 points

Thanks for your response

I tried to write F000 into this register. But, I read it and got the F780. Can you help to explain this?

In addition, I attached my all configuration.

Thanks

0 Dengkuan Sun 5 months ago in reply to Dengkuan Sun

Prodigy 240 points

Oh, seemly, I understand this problem. Does that mean that the reserved bits cannot keep "0" so that I cannot read the configured value? However, the bit 15:11 can keep my configured value. Therefore, that is enough that I only check whether the bits 15:11 are corrected. Is that right?

Thanks

0 Eddie LaCost 5 months ago in reply to Dengkuan Sun

TI__Mastermind 44665 points

Dengkuan,

Yes, that is correct. Bits 15:11 are the only bits that will affect the chip. You only need to check these bits.

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FDC2212: Why not to write the register 0x1E (DRIVE_CURRENT_CH0)