am3359 using ecap to capture synchronized input

Desmond Correia97

Other Parts Discussed in Thread: AM3359

Hi,

I am trying to figure out if I can use the ECAP on the AM3359 to capture serial input synchronously on the rising edge of a clock (1.3kHz clock). This is a custom protocol.

It is a serial protocol that send data to the AM3359, the data is sent from the external device on the rising edge of a clock. I want to sample the data line from the external device using the ecap every time a rising edge occurs on the clock.

I have been reading through the ECAP and from what I understand it has a synchronous input mode.

Do you think this is possible using the ECAP?

Regards

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Hi,

What software are you using?

0 Desmond Correia97 over 9 years ago in reply to Biser Gatchev-XID

Prodigy 190 points

I am using Linux. I am not sure if ecap is supported in linux for input capture if not I will write a driver.

After reading through the technical documentation I am little confused as to weather I could sync the capture input using an external clock.

To be technical the clock that I generate for the external device is actually generated by the am3359 using a PWM

0 Biser Gatchev-XID over 9 years ago in reply to Desmond Correia97

TI__Guru**** 393215 points

Currently the eCAP Linux driver supports only PWM mode (processors.wiki.ti.com/.../Linux_Core_PWM_User's_Guide). I'm not sure I understand correctly your use case: do you mean that you have both an external clock and data lines input to the AM335x?

0 Desmond Correia97 over 9 years ago in reply to Biser Gatchev-XID

Prodigy 190 points

Hi Biser,

I need to capture a custom serial protocol I am reverse engineering some hardware. I was originally going to generate a clock using PWM and then capture the input of the data line using input capture capabilities.

After studying the protocol some more I can use SPI to capture the bits. This protocol is not really SPI. I how ever have already successfully worked out the protocol using a scope.

The AM3359 will generate a clock using SPI and sample the data on the rising edge of the clock.
I am having some trouble setting up the SPI correctly though. I will start a new thread with this problem

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am3359 using ecap to capture synchronized input