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RM48L952: RM48L952 USB Device OTG

Tammy Noergaard
Genius 3665 points
Part Number: RM48L952


Hello,

We are using the Hercules Board RM48L952ZWT with the uCOSII OS and V4 USB device stack. We want to configure the RM48 USB for On-the-Go (OTG). In the USB section of the user guide there is a mention of it, but is there any example of how to set the RM48 registers for enabling OTG? Thank you.

  • 0
    TI__Guru**** 198766 points

    Hello,

    Hercules RM4x devices don't support USB OTG.

  • 0 in reply to QJ Wang
    TI__Mastermind 49120 points

    Hello,

    It is true that the USB IP on RM4x does not support OTG functionality. There is a way to get both host and device functions for the same US port though.

    There are two USB host ports and one device port on the part. The second USB host port is multiplexed with the device port. You can use this functionality to switch the port function in software. We don't have an example for this, however.

  • 0 in reply to Sunil Oak
    Genius 3665 points

    HI Thank you, Which port is the multiplexed port exactly when I look at the board? The andorid tablet vendor said the the port would have to behave like  the OTG standard (ID pulled to ground)., Does the device port behave like an OTG port where the ID pin is pulled to Ground?   Please see attached Rm48 manual. Why is OTG mentioned on page 1487 "Table 29-40. Device Status Register (DEVSTAT) Bit Field Descriptions" ? if it is not supported in the USB chapter for the RM48 (SPNU503B–November 2012–Revised August 2013)?  Thank you again.

  • 0 in reply to Tammy Noergaard
    TI__Guru**** 198766 points

    An OTG device can operate either as a host or peripheral. The cable orientation determines the initial roles: host or device. Grounded ID pin is the default A-Device (initial host), but floating ID pin is the default B-Device (initial peripheral). Those features are not supported by USB host module and USB device module on this MCU. BTW, The USB modules on this device do not include an integrated USB transceiver.

  • 0
    Genius 3665 points

    Thank you QJ and Sunil. I as discussing with team alternate routes than USB with RM48. Can the USB ports be cut/jumped by HW engineers to ports that can be configured as UART and then connecting to the other tablet board which has a RS232 port also (we just use the RS232 to USB dongle then to connect them)?

  • 0 in reply to Tammy Noergaard
    TI__Guru**** 198766 points

    Hi Tammy,

    You can develop a adaptor to convert USB to UART using FTDI FT232. BTW, RM48 has two built-in SCI ports.

  • 0 in reply to QJ Wang
    Genius 3665 points

    Hi QJ Thankyou. Let me clarify my question. The TI Tiva board, for example, allows connecting the microUSB port to serial UARTs and used as serial ports like an RS232 even though it is a USB port. Is this possible on the Hercules board? i.e., can any USB port on the Hercules board be configured as an SCI serial port rather than USB?  Thank you.

  • 0 in reply to Tammy Noergaard
    TI__Guru**** 198766 points

    Hi Tammy,

    As TI Tiva board, RM48x HDK also contains a built-in xds100v2 emulator. The mini USB port on RM48 HDK supports JTAG and UART too.

    On RM48 HDK, LINSCI_TX and LINSCI_RX are routed to FTI FT2232, then to MiniUSB port.