AM335x Set GPIO pin high before SPL

pavan krishna

Other Parts Discussed in Thread: AM3359

Dear All,

I am using TiSDK-8 OS, Is it possible to set GPIO pin as OUTPUT HIGH before SPL or anywhere with in a ~1 second after powering up the beagle bone black.

Currently we are setting at "am33xx_spl_board_init(void)" function which is taking 1.7 seconds to make it as HIGH. But we have set less than a second.

Awaiting for your replies,

Thank you!!

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Hi,

The only possibilites are to use a GPIO that defaults to high at reset release time, or place an external pullup resistor on the line.

0 pavan krishna over 9 years ago in reply to Biser Gatchev-XID

Expert 1010 points

Thank for your reply,

Can you please help me in finding the GPIO pin?

0 pavan krishna over 9 years ago in reply to pavan krishna

Expert 1010 points

After verifying the datasheet of am3359 reference manual found that few gpio pins which have BALL RESET STATE as HIGH and BALL RESET REL. STATE as HIGH and they are GPIO3_7,GPIO3_8,GPIO2_2 and few ...., So to verify that when we reset the board these pins status will held high?

0 Biser Gatchev-XID over 9 years ago in reply to pavan krishna

TI__Guru**** 393215 points

Yes.

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

TI__Guru**** 393215 points

You should also note that these pins will only have a weak internal pull-up turned on by default. They will not be driven high until software configures the output enable. So your use case assumes the signal does not have leakage paths to ground that will pull the weak pull-up below VIH min.

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AM335x Set GPIO pin high before SPL