Does QDEC support a Incrementwheel with Dual Optical Sensor and Comparator circuit?

[Roene]

Hi there

I am stuck. My incremental wheel with photocell and comparator circuit does not work if the QDEC hangs on it. But seperately it works fine.

When I hang it to the nordic QDEC the signals from Phase A and B seems to be connected in a way. But it should be a normal quadrature signal. They must be shifted and switch directly from 0 V to 3 V. Not with this kind like stairs and at the same time.

Thats the schematic:

I'm using a TCUT1600X01 Dual Channel Transmissive Optical Sensor with Phototransistor Outputs and an LMC 6482.

With SDK v15.0.0 and the settings done.

Does anybody has an idea what's wrong?

Thank you!

[Håkon Alseth]

Hi,

 

Are you by any chance powering the nRF with VDD_NRF != 3V, and have enabled pull-resistors on the NRF input GPIOs?

If that is the case, I'd recommend that you try with a series-resistor on both inputs (15k, since you already use this value).

 

Best regards,

Håkon

[Roene]

Hi Håkon

Thank you for your answer. Yes I'm powering the nRF with VDD_NRF == 3V. I also tried with 15k resistors on both inputs. The result is the same. The signals switchs not phase shifted and have this stairs.

I think it could be something with the internal circuit of the nRF?

[Håkon Alseth]

The only thing I can think of is if the IOs are already used by another peripheral. Which GPIOs are connected to the signals QDEC_PHASE_A and QDEC_PHASE_B ?

 

Cheers,

Håkon

[Roene]

QDEC_PHASE_A is on P0.09 and QDEC_PHASE_B on P0.10

Greetings

[Håkon Alseth]

Those are the NFC pins by-default, and in order to use these as normal GPIOs, you need to add the define "CONFIG_NFCT_PINS_AS_GPIOS" to your project and recompile/flash the device.

Could you do this and see if it behaves as indented afterwards?

 

Cheers,

Håkon

[Roene]

Thank you very much Håkon! It was exactly this. Now everything is working fine.

Thank you. Have a nice day!

cheers,

Roene