CC2652RB: Sensor Controller Studio: Quadrature Encoder example / ideas

Bevan Weiss

Part Number: CC2652RB

Hi,

The datasheet lists one of the uses for the sensor controller as being "Quadrature decoder for polling rotation sensors". However when I look at the available configuration options for the GPIO event detection, it only allows a single edge to be selected. So it seems that it would be either quite complicated, or quite restricted in regards to implementing a quadrature decoder.

Is there an example project for reference on the quadrature decoding (to provide a position indication)?

I've looked through the included examples, and nothing appears to come very close. The Hall Effect sensor project is really only a stall monitor.

What would have been ideal is if it were possible to have the Sensor Controller get triggered based on either a rising or falling edge from either Channel A or Channel B. Then it would be a simple case of testing the inputs against previous input state, to determine if rotating CW / CCW.

Regards,

Bevan Weiss

over 2 years ago

0 Clément over 2 years ago

TI__Guru* 94028 points

Hi Bevan,

Have you reviewed this specif SimpleLink Academy lab? https://dev.ti.com/tirex/content/simplelink_academy_cc13x2_26x2sdk_5_20_01_00/modules/sensor_controller/sc_02_ulpsense/sc_02_ulpsense.html

Best regards,

0 Bevan Weiss over 2 years ago

Prodigy 55 points

Yes, I have reviewed that specific item. It does not apply to a quadrature encoder.

0 Clément over 2 years ago in reply to Bevan Weiss

TI__Guru* 94028 points

Hi Bevan,

I haven't point you to the right lab. Please see this one: https://dev.ti.com/tirex/content/simplelink_academy_cc13x2_26x2sdk_5_20_01_00/modules/sensor_controller/sc_03_custom_routines/sc_03_custom_routines.html

Regards,

0 Bevan Weiss over 2 years ago

Prodigy 55 points

The new link does indeed exactly relate to a quadrature encoder. But it appears to be implementing this in a poll-mode, i.e. the code is forever looping and comparing the current input state vs the previous input state.. for a low power implementation this doesn't seem like it would be good.

I would have expected something to be possible as an edge triggered system, or am I missing something from the custom routine example linked?

I see that the example gets us down to 28 instructions for one cycle of the loop... but it just keeps running the loop. What I would have liked to see is where on a change of state, the Sensor Controller is triggered, does the update, and can then go to sleep until the next change of state..

0 Clément over 2 years ago in reply to Bevan Weiss

TI__Guru* 94028 points

Hi,

You are right, this is example provided for educational purposes. To be integrated to an actual product, you will be required to trigger the measurements only when required. The "right moment to take some measurement" depends on your design, on your requirements, your use case, etc.

Best regards,

Bluetooth®︎

Bluetooth forum

CC2652RB: Sensor Controller Studio: Quadrature Encoder example / ideas