AM3351: AM335x Rise and Fall Time Limitation

Hello Ray Vincent

Thank you for the query.

Please refer to the datasheet for the electrical timing.

Can you please also help me understand the pin/signal you are interfacing.

Regards,

Sreenivasa

Hello Ray Vincent

Thank you for the query.

Please refer to the datasheet for the electrical timing.

Can you please also help me understand the pin/signal you are looking to interface.

Regards,

Sreenivasa

Hi Sreenivasa,

Good Day. I’m trying to interface Pin T1 and T2 as Encoder Input.

Best Regards,

Ray Vincent

Hello Ray Vincent

Greetings to you.

Thank you for the inputs.

Are you looking to count the pulses or capture time related information between pulses?

Mine has about a 1-2 ms rise/fall time: Based on this input i assume you are looking to count.

Regards,

Sreenivasa

Hi Sreenivasa,

Good Day. I’m trying to generate an interrupt every time someone rotates the encoder one step further. But sometimes I get about 10 interrupts and sometimes only one. I would expect that the Peripheral only generates 1 interrupt.

Best Regards,

Ray Vincent

Hello Ray Vincent

Thank you for the inputs.

I consulted our device expert (Paul Eaves) and below is the assessment provided 

Based on the results, it sounds like there is more noise in the system than hysteresis on the input buffer and the slow changing signal allows noise to generate glitches inside the device as the signal slowly crosses the switching threshold of the input buffer.

The recommendation is to insert a discrete buffer with large hysteresis in the signal path to provide AM335x with a fast rise/fall signal. A signal with less than 10ns rise/fall would be preferred.

Regards,

Sreenivasa

Hi Sreenivasa,

Good Day.  It would be great if we can find a software Solution to this Problem. Is there any Debouncing register active when the Pin is configured in Eqep Mode?

Best Regards,

Ray Vincent

Hello Ray Vincent

Thank you for the note.

I talked to the experts and recommended the above solution.

I am not aware of a workaround that you are looking for.

Regards,

Sreenivasa