TMS320F280025C: Impedance of GPIO before power on

Chun-Lin Chen

Part Number: TMS320F280025C

Hi Gurus:

I want to know the impedance before GPIO when no power apply on MCU.

I have application need to connect two C2000 device together, and one use GPIO32 which also can be as boot mode select pin.

To prevent undefined boot behavier, I need to know the state/impedance or is it open-drain or something.

The only thing I know is during power on, all GPIO is high impedance state, but no information about before power on state.

Thanks, best reguards

over 2 years ago

0 WW over 2 years ago

Intellectual 565 points

Hi. Use an external pull-up or pull-down resistor on the GPIO32/boot mode select pin. This will ensure the pin is in a known state before and during power-on.

0 Chun-Lin Chen over 2 years ago in reply to WW

Prodigy 207 points

Hi, thanks for the reply, but the situation is the pull-up resistor is not working because the MUC pin pulldown the voltage fron I2C bus.

Is there any other solution to workarounf this issue?

+1 Vince over 2 years ago in reply to Chun-Lin Chen

TI__Mastermind 19795 points

Hi Chun Lin,

Thanks for your question. As WW mentioned, the only correct way to ensure boot pin behavior before and during power up is with a pull up or pull down resistor. There is no other safe way to ensure this.

I apologize if this is not what you are looking for but that is the only way this can be ensured.

Regards,

Vince

C2000™︎ microcontrollers

C2000 microcontrollers forum

TMS320F280025C: Impedance of GPIO before power on