EK-TM4C1294XL and PB1 (TARGET_VBUS)

Peter Ivanov

Hi,

can I harm the MCU by configuring PB1 as output? VBUS's 5V is directly connected to this pin. I think accidentally configured to output. Now the simple blinky example is not working.

Thanks,

Peter

over 11 years ago

0 Amit Ashara over 11 years ago

TI__Guru**** 244440 points

Hello Peter,

If driven a 0V, then you may have caused excessive current sink into the device.

Regards

Amit

0 Peter Ivanov over 11 years ago in reply to Amit Ashara

Prodigy 100 points

Thanks for answer. I expected this one. Is it necessary connect VBUS to the MCU directly? Can a 10K resistor protect the IC?

0 Amit Ashara over 11 years ago in reply to Peter Ivanov

TI__Guru**** 244440 points

Hello Peter,

The VBUS pin draws some current from the VBUS pin. having a large resistance would cause voltage drop ending up in VBUS being detection threshold.

Typically if the USB function is not to be used then on the EK-TM4C129

Are you able to connect to the TM4C129 via the debugger and load program?

Regards

Amit

0 Peter Ivanov over 11 years ago in reply to Amit Ashara

Prodigy 100 points

Hi Amit,

I can connect and download a program, but some of the GPIOs seems to be broken. LEDs D1 and D2 cannot be switched on ("blinky" example tried to use D1). However D3 and D4 are OK.

I have been developing USB host, so I need VBUS. As a workaround I'm injecting VBUS externally to the device and usb_host_msc and usb_host_keyboard examples work this way.

Best regards,

Peter

0 Amit Ashara over 11 years ago in reply to Peter Ivanov

TI__Guru**** 244440 points

Hello Peter,

You might have other components not working also. It would be good to replace components as you find them not functional. Sometimes we don't know when they would be needed

Regards

Amit

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EK-TM4C1294XL and PB1 (TARGET_VBUS)