Beaglebone Black auto restart when use PWM2A as background light of AT070TN83

chancen guo

Hi all,

Now I connect LCD 7 AT070TN83 with my BB Black, ehPWM2A as background light.

Unfortunately, system always restart if I connect the ehPWM2A port as PWM background light. If i disconnect the PWM port and restart by hand, everything is OK!

What's reason? What should I do? Thanks!

over 11 years ago

0 Biser Gatchev-XID over 11 years ago

TI__Guru**** 393215 points

Hi Chancen,

Where do you get +5V for the LED backlight from? If it's from the BBB then it's possible that you are overloading the +5V supply.

0 chancen guo over 11 years ago in reply to Biser Gatchev-XID

Intellectual 330 points

Hi Biser,

Thanks for your reply, I use the expansion connector of BBB VDD_5V or SYS_5V, both have the same problem.

If it's overloading +5V, which port can I get 5V output?

0 Biser Gatchev-XID over 11 years ago in reply to chancen guo

TI__Guru**** 393215 points

Are you providing power to the BBB from an external adapter or through USB?

0 chancen guo over 11 years ago in reply to Biser Gatchev-XID

Intellectual 330 points

No, I used 5V 3A DC supply, the maxium current of the LCD won't be over 1000mA.

0 Biser Gatchev-XID over 11 years ago in reply to chancen guo

TI__Guru**** 393215 points

Probably there is a glitch in the 5V rail when the LCD backlight starts. Have you tried to supply 5V to the LCD from a separate source?

0 chancen guo over 11 years ago in reply to Biser Gatchev-XID

Intellectual 330 points

Hi Biser,

I have tried a separate 5V source,unfortunately, the problem is always there.

What should I do?

0 Biser Gatchev-XID over 11 years ago in reply to chancen guo

TI__Guru**** 393215 points

Have you checked your supply voltages, reset line with an oscilloscope, to try and establish where the problem comes from?

0 Biser Gatchev-XID over 11 years ago in reply to Biser Gatchev-XID

TI__Guru**** 393215 points

Please check the PWRONRSTn and WARMRSTn signals when the problem occurs.

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Beaglebone Black auto restart when use PWM2A as background light of AT070TN83