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MSP430 USB design guide

paddu
Intellectual 915 points
Other Parts Discussed in Thread: TPD4E004, MSP430F5529

Hi,

 

Our customer is using MSP430F55xx and I would like know if 

there is any document or reference design for MSP430F55xx USB circuit.

like recommendation for ESD protection etc.

 

Regards.

Paddu

  • 0
    Intellectual 915 points

     

    Hi,

     

    Previously there was a document called "Starting a USB Design with MSP430"

    and there was a TI's recommendation for certain basic circuitry for USB interface

    as shown below, is this valid for recent MSP430F55xx devices?

     

    Please let me know there is any other things to be considered.

     

    Regards..

    paddu

  • 0 in reply to paddu
    Genius 4680 points

    > is this valid for recent MSP430F55xx devices?

    It's fine.

    In addition, attach 220nF capacitor to Vusb pin.

    The TVS diode array, TPD4E004, is fine when the USB power domain on the MSP430 is supplied by on-chip 3V3 regulator, sourced by VBUS pin. Usually, you'll configure the chip like so.

    But if the USB power domain is supplied by other power source like a battery over Vusb pin, TPD4E004 disturbs disconnection detection at VBUS pin. The TPD4E004 high-side diode, across D+ and VBUS, supplies voltage to VBUS pin over D+ pull-up resistor. For this configuration, TVS diode array with just low-side diodes is better.

    ON Semi NUP4060AXV6
    http://www.onsemi.com/pub_link/Collateral/NUP4060AXV6-D.PDF
    ESDAULC6-3BP6
    http://www.st.com/stonline/products/literature/ds/13704/esdaulc6-3bf2.pdf

    Tsuneo

  • 0 in reply to Tsuneo Chinzei
    Guru 17650 points

    Hi,

    you can have a look at the design files of the MSP-EXP430F5529 Experimenter Board too (MSP-EXP430F5529 Experimenter Board PCB Design Files).

    The board can be powered by various power sources, so it's as a perfect reference for your custom designs.

    Rgds
    aBUGSworstnightmare 

  • 0 in reply to Joerg Quinten
    Intellectual 915 points

     

    Thank you all for the useful information.

     

    In our case we will use external LDO(sourced either from battery/VBUS when present) for DVCC

    and the USB power domain on the MSP430 is supplied by on-chip 3V3 regulator.

     

    With your suggestion, I refered the circuit from the EXP and rewrote as below,

    if possible could you please let me know if there is something missing. 

    Regards.

    Paddu.

  • 0 in reply to paddu
    Genius 4680 points

    Fine.
    As you don't mount bootloader push switch, R24 1M ohm resistor is redundant, though it does no harm. :-)

    Tsuneo

  • 0 in reply to Tsuneo Chinzei
    Intellectual 915 points

    Hi Tsuneo,

     

    Thank you very much for the confirmation.

    If possible could you please let me know if you there is any PCB Layout guideline or any

     

    layout examples for USB design.

    I know there is gerber files for EXP board, but the board is quite complicated with many additional features

    and it would be helpful if there is some basic information about USB Hardware Design like USB signal routing,USB traces etc

     

     

    Regards.

    Paddu.

  • 0 in reply to paddu
    Genius 4680 points

    Cypress distributes this appnote for board layout of High-speed (480Mbps) device.

    High-speed USB PCB Layout Recommendations
    http://www.cypress.com/?docID=25406

    As the USB engine on MSP430 is Full-speed (FS: 12Mbps), above recommendations are too much.
    But a couple of points are still fine for FS.
    - Layout D+/D- trace closely in parallel.
    - Isolate connector shield from GND plane
    - "USB Peninsula" on above appnote

    Tsuneo

  • 0 in reply to Tsuneo Chinzei
    Intellectual 840 points

    Hello Gentlemen,

    I had one further question please.  How would one automatically detect if a USB cable has been interfaced to the MSP430F5529?

    Thanks,

    Ali.

     

  • 0 in reply to Ali Movahedi
    Genius 4680 points

    > How would one automatically detect if a USB cable has been interfaced to the MSP430F5529?

    Plug in / plug off of USB connector is detected by the voltage change at VBUS (5V supply) pin of the USB connector. The chip mounts a comparator to detect this voltage change.

    See this section of the User's Guide
    http://www.ti.com/litv/pdf/slau208h

    29.2.2 USB Power System
    - VBONIFG, USBBGVBV

    On the examples in MSP430_USB_Developers_Package_3_0_0_0,
    - VBONIFG flag raises USB interrupt
    - The USB ISR, iUsbInterruptHandler() is called with USBVECINT_PWR_VBUSOn
    - The callback, USB_handleVbusOnEvent() (usbEventHandling.c), is called

    Tsuneo

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