Linux/PROCESSOR-SDK-AM335X: PWM sync to system time or clock

hardik gohil

Prodigy 180 points

Part Number: PROCESSOR-SDK-AM335X

Tool/software: Linux

Hello,

I am using ECAP0 to generate pwm pulse from AM335x.

how can I synchronize pwm pulses with system time or system clock.

Now the PWM pulses are generated independently.

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Hi,

There is a sync input to eHRPWM0 module from an external pin, named ehrpwm0_synci. This is daisy-chain propagated through the ePWM and eCAP modules. See section 15.1.2.1 of the AM335x TRM Rev. P.

0 Hardik gohil over 8 years ago in reply to Biser Gatchev-XID

Prodigy 100 points

Hello,

so you mean I need to provide the external input ? what should be external input I should provide ?

Is there any way internally to mange the synchronization ?

0 Biser Gatchev-XID over 8 years ago in reply to Hardik gohil

TI__Guru**** 393215 points

Please read my previous post more carefully.

0 Hardik gohil over 8 years ago in reply to Biser Gatchev-XID

Prodigy 100 points

I read but I couldn't understand.

Can you please elaborate ?

Thanks in Advance

0 Biser Gatchev-XID over 8 years ago in reply to Hardik gohil

TI__Guru**** 393215 points

What exactly didn't you understand?

0 Hardik gohil over 8 years ago in reply to Biser Gatchev-XID

Prodigy 100 points

what external input I need to give to ehrpwm0_synci so that CPU system time is sync with PWM output generation ?

0 Biser Gatchev-XID over 8 years ago in reply to Hardik gohil

TI__Guru**** 393215 points

The best solution would be to use an external clock oscillator to provide both system clock and ehrpwm0_synci signal.

0 Hardik gohil over 8 years ago in reply to Biser Gatchev-XID

Prodigy 100 points

this looks bit complex since I need to provide external oscillator to cpu.

My CPU is getting sync to GPS.

how can I use GPS output to PWM sync input ?

0 Biser Gatchev-XID over 8 years ago in reply to Hardik gohil

TI__Guru**** 393215 points

What is the GPS output?

0 Hardik gohil over 8 years ago in reply to Biser Gatchev-XID

Prodigy 100 points

IRIG-B which is 100 Pulse per second.

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Linux/PROCESSOR-SDK-AM335X: PWM sync to system time or clock