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F2806x ISO controlCard serial comm

Gary H
Expert 1855 points

Is it not possible to use the J1 USB JTAG connector on the F28069 ISO ControlCard for serial communication? When connected to this connector I am able to use the JTAG and a comm port is created on my PC. When I write data from the control card via the TX_GPIO_29 pin, I do receive data on the PC comm port but it is garbage data. The baud rates and parity are OK on both sides. Just wondering if this is possible or do I have to use the HVKit JP1 connection as a comm connection.

I was able to get basically the same code to work on my 28027 version via the JP1 connector, but wondering why on the F28069 ISO control card the J1 comm does not seem to work. The blue light are blinking when I send data.

  • 0
    TI__Guru 57255 points

    Hi Gary,

    Yes, it is possible to use the F28069 ISO cCARD's serial communication section.  I have had it work before, just perhaps not with your exact setup.

    However, your question involves getting this controlCARD's ISO comport to work with the 'HVKit'.  My guess is that it should be possible here as well, but there are potential contention possibilities between which HVKit you are using and the controlCARD.  Usually this involves the RX path not the TX path though.

    Which 'HVKit' are you using?

    If you have one available, I might recommend trying your F28069ISO cCARD on the Experimenter Kit's Docking Station (and making sure that the Docking Station doesn't create GPIO28 contention).  This should be a simpler system, and may allow you to more easily debug what is going on.


    Thank you,
    Brett

  • 0 in reply to Brett Larimore
    Expert 1855 points
    You are correct about the HVKIT I am using. After looking at the schematic for the HVKIT it does tie the GPIO28 to the output of the opto isolator. I am using the HVKIT that has the yellow board. I cannot seem to find where the board version is, but his is the one that works with the InstaSpin. I will switch to using the HVKITs iso JTAG/com port to make sure my 28069 code is working. I know this port works because I use it often with another 28027 card. My main question is that the F28069 ISO control card FTDI chip's comm port will work. You have answered that for me. I will forge forward and once I figure it out I will report back.
  • 0 in reply to Gary H
    Expert 1855 points

    I figured out what I was doing wrong. I assumed when I switched to the 28069 driver files they would take into account that the 28069 runs at 90MHz, so when I used the SCI_BaudRate_115_2_kBaud define to set the baud rate it gave me the wrong baud because the 28069 SCI.h file stills assumes you have a 60MHz clock with the LSPCLK divided by 4. I also noticed that in the instaspin clk setup in hal.c they set the LSPCLK to divide by One, so I changed it to divide by 4.

    // set the low speed clock prescaler Gary_H changed from divide by 1 to divide by 4 for sci
    CLK_setLowSpdPreScaler(obj->clkHandle,CLK_LowSpdPreScaler_SysClkOut_by_4);

    I then changed the following in SCI.h

    SCI_BaudRate_115_2_kBaud = 23 //!< Denotes 115.2 kBaud Gary_H changed from 15 to 23

    The serial port then began working for the J1 FTDI ISO circuit as far as being able to transmit from the controlcard to the PC. I still could not transmit from the PC to the Controlcard because of the HVKIT contention on GPIO28. I did get both TX and RX working when I switched to the HVKIT's JP1 isolated port. I think if I add a simple 2K resistor in series with the U7 pin 7 ISO7220 chip I will break the contention on SPIO28 and be able to use either the controlcard ISO comm or the HVKIT ISO comm.

    I did place a 2K resistor in series with U7 pin 7 on the HVKIT (R1.1) and this did allow me to use the ControlCard J1 connector as the comm or I could use the HVKIT onboard JP1 connector as the comm. It is convenient to use the ControlCard Isoaloated JTAG as the comm because this allows me to change my code and view comm data as I run in debug mode. As mentioned below you do have to make sure the SW3 switch is in the correct position and also that the HVKIT JP1 circuit is disabled via J5. I inserted a photo of my 2K resistor mod. Its a little messy, but gets the job done.

  • 0 in reply to Gary H
    TI__Guru 57255 points

    Note that the ISO controlCARD has a switch to enable/disable its on-card FTDI UART RX path to go to GPIO28 of the MCU.  

    If I remember correctly, the HVMTRKITs do NOT have this type of switch for the UART RX path of its FTDI chip.