• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Subscribers 81 subscribers
  • Views 3809 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

C2000 USB Docking Station: EMU0 & EMU1

Brian Walsh
Intellectual 460 points
Other Parts Discussed in Thread: CONTROLSUITE

Hello everyone,

I am planning to develop a PCB with a F28335 microcontroller. To be able to program it, i would like to use a USB-JTAG-circuit on the board.

Examining the "USB Docking Station R3" schematic, I realized, that the pins EMU0 & EMU1 are just connected to the additional JTAG socket. Do I not need them for programming the µC ?

I also found the XDS100v2 schematic, which is more complex than the Docking Station circuit. I don't think, that I need the option to program a lot of different controllers (CPLD), as I just want to program the installed F28335. Increased speed would be a nice thing though. I guess it's not possible to take the v1 and just change the FT2232D to the FT2232H for higher speeds !?

What would be your suggestion ?

Thank you in advance.

  • 0
    Guru 192875 points

    Hi,

    Brian Walsh said:
    Examining the "USB Docking Station R3" schematic, I realized, that the pins EMU0 & EMU1 are just connected to the additional JTAG socket. Do I not need them for programming the µC ?

    These pins are not required for programming the uC.

    Brian Walsh said:
    Increased speed would be a nice thing though. I guess it's not possible to take the v1 and just change the FT2232D to the FT2232H for higher speeds !?

    Nah.. simplyfollow the BOM.

    Regards,

    Gautam

  • 0 in reply to Gautam Iyer
    Intellectual 460 points
    Thank you for the reply.

    Maybe I should go with the v2, because of the higher programming speeds.

    Is there any reason I should use the "VBUS"-voltage (USB +5V) instead of any locally available +5 V ?

    I think about excluding the voltage follower circuit and directly connect the "VTARG" to the +3,3V of the F28335 VDDIO (the only target). I am just not sure about the "PWRGOOD" line to the CPLD, because there is no documentation about it's precise functionality. Should I tie this to VCC ?

    ~Brian
  • 0 in reply to Brian Walsh
    TI__Guru 57255 points

    Hi Brian,

    As you mention, the xds100v2 is faster than the xds100v1.  If speed is you biggest concern, then I would recommend just placing a JTAG header (and using something like the xds200).

    As long as you tie the grounds together, using a local +5V should be adequate. 

    This group is not too familiar with the specifics of the various emulator schematics.  I might recommend posting your most recent questions to the code composer forum.  I believe the functionality of the voltage follower, etc is to ensure that the JTAG pins going to the C2000 device are Hi-Z until power is good (I'm not 100% sure though).


    Thank you,
    Brett

  • 0 in reply to Brett Larimore
    Intellectual 460 points

    Thank you for the reply and the CCS forum hint.

    Brett Larimore said:
    I believe the functionality of the voltage follower, etc is to ensure that the JTAG pins going to the C2000 device are Hi-Z until power is good (I'm not 100% sure though).

    This would make sense regarding the PWRGOOD signal.

    If I use the XDS100v2 design for an onboard programmer, the target is permanently connected and PWRGOOD would also be constantly high. That's why I would still tend to tie the CPLD Pin 16 (PWRGOOD) to VCC (TI's schematic below).

     

    Has anyone used this reference design for an onboard programmer ?

    ~Brian

  • 0 in reply to Brian Walsh
    TI__Guru 57255 points

    Brian,

    What you have mentioned makes sense to me.  Double-checking on the Code Composer forum might be prudent though.

    ===

    I might recommend taking a look at the F28M36x controlCARD's schematics (especially page 8 & 9).  Here a minor variant based on the xds100v2 was used.  It's probably not quite as robust on the emulation-side of things, but has been working well for our evaluation tool:
    \controlSUITE\development_kits\~controlCARDs\TMDSCNCD28M36_v1_2\R1_1\
    (note that A:R6 in that schematic should actually be 12K)

    The emulation logic here is very similar to what you could do on the F28335. 

    Note that EMU0 and EMU1 are mostly used for trace, but also may be useful for setting the device in wait-in-reset mode.  They may or may not be useful for you.
    If you don't use them (and don't want the circuitry for them into your design) you should pull the C2000 pins weakly high.  Note that SCI boot mode can also hold the device in reset.
    http://processors.wiki.ti.com/index.php/JTAG_Connectors#Q:_What_are_the_EMU0.2F1_pins_used_for.3F)

    The emulation logic on the controlCARD features isolation between the emulator and C2000 chip.  This is to enable debugging while the chip is actively controlling a power systems.

    If isolation is used, some kind of switch on TRSTn is absolutely necessary - as it allows you to switch between using the emulator and being able to boot-from-flash,SCI,etc.


    Thank you,
    Brett