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TMS320F28035: GPIO34 and GPIO37 Boot Pin Internal Pulls

Stuart Baker
Genius 10540 points
Part Number: TMS320F28035

Is there internal pullup or pulldown on GPIO34 and/or GPIO37 (TDO) on reset (at the time that these boot pins are sampled)?  Are external pulls required?

In the Datasheet, based on what I read in section 4.2, it would seem that both pins would have internal pullups.  However, based on Table 4.1, it would seem that GPIO37 (TDO), at least, has no internal pullup or pulldown.

Thanks,

Stuart

  • 0
    TI__Guru* 95315 points
    Whether or not to have an external PU is up to the application. The internal PUs are weak, as the datasheet numbers show. If an application chooses an external PU to augment the internal PU, the value of the external resistor must be chosen in a way that the MCU (or external circuitry) is able to drive a low-level on that pin comfortably. In the latter case, the VIH/VIL levels should not be violated.

    I am double-checking with the Design team, but according to the spec, it does appear TDO pin has an internal PU.
  • 0 in reply to Hareesh Janakiraman
    TI__Guru* 95315 points
    I confirmed that TDO does have an internal PU.