TSC2007: How to switch pullup resistor

Bill Shih

Prodigy 50 points

Part Number: TSC2007

Hi TI

We are developing Android A11 with kernel 4.19

How could I switch PENIRQ pull-up resistor?

I tried several times but failed, with i2c clk 100kHz and 400kHz.

I think our i2c is normal because it could receive xy data from chip.

This is how I run the command for switch PENIRQ pull-up resistor:
err = i2c_smbus_write_byte(ts->client, 0xb1);

but kept return fail(-107).

Is there any sample code or reference for it?

Thank you

over 2 years ago

0 Tom Hendrick over 2 years ago

TI__Guru**** 168635 points

Hi Bill,

Your command seems right assuming you have the correct address for the TSC2007. The PENIRG pull-up is described in the Electrical Characteristics table on page three and the first paragraph of page 19 under the Touch Detect heading. Unfortunately I do not have any specific code to share with you that implements the pull-up swap option.

0 Bill Shih over 2 years ago in reply to Tom Hendrick

Prodigy 50 points

Hi Tom

From the Table 3, page 25 in TSC2007 datasheet, the Setup command has no ACK.

Does that mean TSC2007 wouldn't send ACK back, and thus I got failed return from the i2c_smbus_write_byte function?

Thanks

0 Tom Hendrick over 2 years ago in reply to Bill Shih

TI__Guru**** 168635 points

Hi Bill,

Correct, the setup command does not send an 'ACK', so I believe that does explain the failed return in your function.

0 Bill Shih over 2 years ago in reply to Tom Hendrick

Prodigy 50 points

Hi Tom,

If it is that way, then is there any way to know the PENIRQ pull-up resistor has been switched?

Thanks

0 Tom Hendrick over 2 years ago in reply to Bill Shih

TI__Guru**** 168635 points

Hi Bill,

From the analog perspective, you should see a small difference in the X/Y driver waveforms - faster response with the 90k option, slower with the 50k. I am not aware of any way to verify the setup command via software.

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TSC2007: How to switch pullup resistor