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TMS320F2808 SCI-A on Docking Station USB-EMU [R3]

Mike Shaw
Intellectual 460 points

Other Parts Discussed in Thread: CONTROLSUITE

Hi,

Apologies if this has been covered before, I cannot find anything in the Forums...

I have a Docking Station USB-EMU [R3] with an F2808 ControlCARD fitted.  

I've used ControlSUITE and taken the SCI-Echoback example from the F2807 Code Examples and ported it to the F2808 device.  I can successfully transmit a message from the F2808 to PC (RealTerm), however, when I try to send a message back from RealTerm to the F2808 I do not receive it.

I've been through the registers several times, checking the various settings and I cannot see anything wrong from the Software point of view.  I loaded the sci_loopback_interrupts Code Example and this works fine (I'm aware it's not communicating with the PC).

The FTDI chip is ok, I'e checked the configuration with FT_Prog.

I suspect the problem is in the USB - UART bridge and the signal isn't reaching the Processor.  After a bit of searching I found that R18 on the ControlCARD has to be 0ohm (which it is) and that J9 on the docking station has to be jumpered (which it is now).  I still cannot receive any data from RealTerm.

Tomorrow I will connect the scope to try and establish what is happening but I thought I would ask here in case there is an easy/quick solution that I've missed.

Or another alternative, does anyone have any working code for the F2808 that allows UART comms on the Docking Station?

Any assistance appreciated.

Mike.

  • 0
    TI__Guru 57255 points

    Hi Mike,

    Very close.  I think the below will help you.

    The Docking Station + F2808 cCARD combination gives you two UART connections options:

    1. Via J3 on the Docking Station (a path through U4+U5 on the 'F2808 controlCARD)
      1. unjumper J9 on the Docking Station
      2. make sure that R18 on the cCARD is populated
    2. Via the FTDI's USB-to-UART bridge -
      1. jumper J9 on the Docking Station
      2. disable the U4/U5 path by removing R18 on the cCARD

    Try it out and let us know if this resolves your issue.


    Thank you,
    Brett

  • 0 in reply to Brett Larimore
    Intellectual 460 points

    Hi Brett,

    Thankyou for the quick reply.

    So, that is remove R18 (see attachment) completely so there is a break in the track?  I traced this back in the ccard schematic and I believe R18 is connected to J3 RX, so I assume that this possibly floats when J3 is not in use and causes issues on the RX line from the USB bridge?

    I will do this first thing in the morning when back at work and report back, thankyou.

    Mike.

  • 0 in reply to Mike Shaw
    TI__Guru 57255 points

    Hi Mike,

    I am unsure exactly what you're asking above, but hopefully the below will clarify things some.

    If R18 is placed and J9 is also placed, U4 will drive a signal into GPIO28 (SCIRX) and will cause contention with the FTDI's driver which will also be driving.  For you this means that you have to disable one of the paths so that the other path can effectively drive the signal without contention.


    Thank you,
    Brett 

  • 0 in reply to Brett Larimore
    Intellectual 460 points

    Hi,

    Yes, what you have described is essentially what I mean.  

    I will post an update tomorrow when we've removed R18.

    Thanks again,

    Mike.

  • 0 in reply to Mike Shaw
    Intellectual 460 points

    Hi Brett,

    Just for feedback - this has worked ok.

    Thankyou for your help,

    Mike.