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AM3356: USB1_DRVVBUS signal it is not going HIGH always it is staying LOW

ptm
Intellectual 270 points
Part Number: AM3356
Other Parts Discussed in Thread: TPS2546

Hi,

In one of my design I am using TPS2546  USB controller and it is interfaced to AM3356 . We configured USB1 as  host but when we connect the thumb drive it is not detecting. 

below is the configuration we are using 

USB1_ID is NC, USB1_DRVVBUS is connected to TPS2546 enable pin , and  USB1_VBUS is connected to TPS2546 output and to the pin1 of USB A connector.

the software used is same as beagle bone EVM.

when we probed the USB1_DRVVBUS signal it is not going HIGH always it is showing LOW.

when we did read-back of register related to USB1 it is showing correctly (configured for HOST).

When we connect USB1_ID to LOW then also we are seeing  USB1_DRVVBUS always LOW.

Can anybody tell me what will be the issues ?

  • 0
    TI__Guru**** 393215 points
    Hi,

    Please check your schematics. Refer to processors.wiki.ti.com/.../AM335x_Schematic_Checklist If possible post the USB portion of the schematics. Also check the pinmux settings for USB1_DRVVBUS. Please post the Linux version you use and the log file.
  • 0 in reply to Biser Gatchev-XID
    Intellectual 270 points

    Hi,

    Here i am attaching the portion of the schematic related to USB controller.

    Figure 1 is the initial configuration we used in the design : In this configuration we are not able to detect the thumb drive. Later we modified the schematic.

    Figure 2 is the modified schematic. After modification we are able to detect the thumb drive and we did few measurements to understand why circuit in the Figure 1 is not working.

    When we measured the output of the TPS2546 with respect to USB1_DRVVBS signal i.e enable signal of the TPS2546 we observed that 5V is appearing at the TPS2546 output (USB1_PWR)  after 200ms.

    But As per TPS2546 datasheet Propagation delay is 0.25ns (TYP).

    Can anybody tell me why my First circuit (Figure 1) is not working  correctly ? and also in the case of Modified circuit (Figure 2) from where  200 ms delay  i s getting added / introduced ?

  • 0 in reply to ptm
    TI__Guru**** 169071 points

    Hi,

    I don't see any difference between the two figures, other than the 2nd has a note saying USB1_VBUS is connected to SYS_5V directly. I can explain why the modified circuit works, but I don't know where the 200ms delay comes from, maybe the TSP2546 team has some idea.

    For the AM335x USB controller to work in host mode, after turning USB1_DRVVBUS pin high, USB1_VBUS pin should sense >4.4V within 100ms; otherwise, USB1_DRVVBUS will be turned low, and the USB controller will not transition to host mode. If there is 200ms delay on the output of TPS2546, the USB controller will not be able to detect any usb device on your first circuit.

  • 0 in reply to Bin Liu
    Intellectual 270 points
    Hi,

    Thank you for quick reply,
    can you please connect this to TPS2546 team.
  • 0 in reply to ptm
    TI__Guru**** 169071 points
    Let me move this thread to the TPS2546 team.
  • 0 in reply to Bin Liu
    TI__Mastermind 32891 points
    I'm from the TPS2546 team.

    Can you please tell me the pin settings for CTL1, CTL2, CTL3, and ILIM?

    I also need to know what your target current output and any of the BC 1.2 or other power management modes you wish to suppor.

    This will help me support your questions.
  • 0 in reply to Chuck Branch
    Intellectual 270 points
    Hi,

    By default i am setting CTL1 = 0, CTL2 = 1, CTL3 = 1, ILIM = 0 and Target current is 1.5 A, any of the BC1.2
  • 0 in reply to ptm
    Intellectual 270 points

    Hi,

    Any update, what will be the issues with TPS2546?

  • 0 in reply to ptm
    TI__Mastermind 32891 points
    The mode you have configured 0110 is DCP_AUTO mode for the TPS2546. This mode is utilized for a charge only mode when the host is in low power mode.

    If you intend the port to have active data, then I suggest you configure it as a SDP or CDP. 1110 or 1111 are good choices.

    If you can provide me a little more detail on you desired system behavior, I can help out more.
  • 0 in reply to Chuck Branch
    TI__Mastermind 32891 points
    I haven't heard back on this thread for nearly 2 weeks, so I am going to mark this as resolved until I hear back on the status.