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BQ25890H: Is DSEL pin connected to USB PHY for OTG?

Simon Paterson
Prodigy 40 points
Part Number: BQ25890H

I'm confused about the role of the DSEL pin. I do not have experience with USB multiplexing, so I don't fully understand the nomenclature.

Should it be connected to the ID pin on the USB header for OTG applications?

If not, should I tie the ID pin on the USB header to GND?

  • 0
    TI__Expert 8230 points
    Hello Simon,

    The DSEL pin is typically used to control a 1:2 multiplexer; the DSEL pin is tied to the control pin (typically a GPIO) of the mux. During the adapter plug-in, the D+/D- lines are first connected to the charger so it can perform the USB detection to set the input current limit. Depending on the result of the detection, if it detects a USB host such as SDP, it toggles to switch the mux and connect the D+/D- lines to the data lines so communication can be established with the host.

    The OTG pin is a different pin that is used to enable/disable OTG boost mode. This pin is typically connected to a GPIO on the host or pulled high to always have OTG mode enabled on the 890H.

    The ID pin is used to identify which device is the host and which is the peripheral. Typically the device you want to act as the host will have the ID pin grounded, while the peripheral with an ID pin floating is the peripheral. Since the 890H will be providing power to the peripheral, the ID pin on the charger's side can be grounded.