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Ignoring state of EN1/EN2 BQ24250

Allen Stuart
Prodigy 240 points
Other Parts Discussed in Thread: BQ24250

Hello, 

I have a micro-controller attached to the EN1/EN2 pins to indicate charge state of the USB port.  For some reason the EN1/EN2 states are not being acknowledged by the device.  I have checked the connection and I have checked the states but the BQ24250 insists they are both logic 0...

Any ideas why it appears to be ignoring them?

Thanks

Allen

  • 0
    TI__Mastermind 25800 points
    Hello Allen,

    Have you tried tying the pins to a specific rail? Tested the voltage level on the EN1 and EN2 lines?

    And when you checked the states, are you saying you read the values of Register #3?

    Do you have an input source or battery attached when you are reading the states?


    Thanks,
    Joel H
  • 0 in reply to Joel Hernandez II
    Prodigy 240 points
    Hi Joel,
    Thank you for the reply. I have tied the pins to the supply rail and measured both EN2 and EN1 in this configuration and directly from the microcontroller. In both cases they are set to '1' '1' (and measured to be such) but the BQ24250 insists that it is '0' '0', using the BQ24250EVM program I read the value in the register, I have a battery attached.

    Thanks
    Allen
  • 0 in reply to Allen Stuart
    TI__Mastermind 25800 points

    Hello Allen,

    That register does not accurately report the state of EN1/2 as intended. Our datasheet needs to be corrected.

    However, that does not mean that the device will function differently. This only affects the register state. 

    Setting the En1/2 pins will still follow the Truth Table presented in Table 1 of the datasheet. You just won't be able to read it. 

    Hope this helps,

    Joel H

  • 0 in reply to Joel Hernandez II
    Prodigy 240 points

    Hi Joel,

    This explains so many of the issues I have been seeing.  Also I notice that the software claims a DCP to be EN1/2 as '0' but the truth table is EN2 = '0' and EN1 = '1' and '0' is a CDP.

    I assume then that as long as the EN1 and EN2 pins are controlled in the correct manner to represent SDP/CDP/DCP the device should charge accordingly.

    Kind regards

    Allen

  • 0 in reply to Allen Stuart
    TI__Mastermind 25800 points

    Hey Allen,

    I'm glad it helps. It's a small glitch in the part.

    But you are correct in assuming. The device will still charge correctly. 

    Regards,

    Joel H