TMS320F2812: GPIO states during start-up

Linda Zhang84708

Part Number: TMS320F2812

Hello Champs,

As described in F281x datasheet figure 5-9:

“GPIO Pins as Input （State Depends on Internal PU/PD)", does that mean at this stage the GPIO states are only determined by internal PU/PD？

If GPIO has been externally pulled up or pulled down, can this also decide the GPIO state at this stage?

Would you please kindly help? Thanks!

Best Regards,

Linda

over 6 years ago

0 Cody Watkins over 6 years ago

TI__Mastermind 42195 points

Linda,

at startup all GPIOs are configured as inputs. Almost all pins have an internal pullup(PU). These are not configurable on this device.

The following pins have no internal PU/pulldown(PD): GPIOE0, GPIOE1, GPIOF0, GPIOF1, GPIOF2, GPIOF3, GPIOF12, GPIOG4, and GPIOG5.
The following pins have an internal pulldown: XMP/MC, TESTSEL, and TRST.
All other pins have a PU.

For more information on this please see the datasheet.

The PUs and PDs are weak on this device. Adding an external PU or PD will overpower the internal PU/PD.

0 Linda Zhang84708 over 6 years ago in reply to Cody Watkins

TI__Expert 6890 points

Hello Cody,

Thank you for your reply.

So that is to say, even if using external pull-up or pull-down, all GPIOs output states at startup are still undetermined, is it right?

Would you please kindly help? Thanks!

Best Regards,

Linda

0 Cody Watkins over 6 years ago in reply to Linda Zhang84708

TI__Mastermind 42195 points

Linda Zhang84708 said:
even if using external pull-up or pull-down, all GPIOs output states at startup are still undetermined, is it right?

No, the GPIO will be an input and that input will be pulled up or pulled down by the external pull resistor.

Regatds,
Cody

0 Linda Zhang84708 over 6 years ago in reply to Cody Watkins

TI__Expert 6890 points

Hello Cody,

Thank you for your kind help.

Best Regards,

Linda

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TMS320F2812: GPIO states during start-up