TMS320F28P650DK: GPIO Impedance Control

Mike Allette

Tool/software:

Hi,

I see that the impedance of he GPIO pins are 70 Ohms. How do you usually route the traces for these pins? Do you control the impedance of the traces for these signals? Do you add series resistance to these signals?

over 1 year ago

0 Joseph Casuga over 1 year ago

TI__Mastermind 40330 points

Hi Mike,

The GPIO pins have a max drive current of 2mA. For a 3.3V rail on VDDIO, ensure that the resistive load connected to the GPIO should not be lower than 1.65k in order not to exceed the current load especially for steady state output. As for routing, match traces with 50 to 100 ohm impedance in order to have good signal integrity for fast switching signals like EPWM or any communication channel that uses these GPIOs.

Regards,

Joseph

0 Mike Allette over 1 year ago in reply to Joseph Casuga

Intellectual 355 points

Hi Joseph,

What is the actual drive output impedance of the GPIO driver of the MCU?

0 Joseph Casuga over 1 year ago in reply to Mike Allette

TI__Mastermind 40330 points

Hi Mike,

Nominal drive output impedance of GPIO is 70ohms.

Regards,

Joseph

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TMS320F28P650DK: GPIO Impedance Control