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EK-TM4C1294XL: TM4C1294NCPDT

Byron Blue
Prodigy 110 points
Part Number: EK-TM4C1294XL

I'm trying to simply send a string to the serial port on another computer.

If I send:

UARTprintf( "%s", "ccccc");

I get 5 "NNNNN" on the other screen.

If I sent:

UARTprintf( "%s", "aaaaa");

I get 5 "OOOOO" on the other screen.

The port is set to:

UARTConfigSetExpClk( UART0_BASE, g_ui32SysClock, 4800,
( UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE |
UART_CONFIG_PAR_NONE));

Something basic is set wrong?

Thank you for any help,

Byron

As a note: I've tried using RealTerm to monitor the output. Same result...

  • 0
    TI__Guru**** 191886 points

    Hi,

      Can you confirm that your terminal window is configured with the same parameters? You are configuring for 4800 baud rate, 8 bit, one stop bit and no parity. BTW, 4800 is extremely slow. I'm not sure about your application. i have seen customers using this slow baudrate for a very long time. 

  • 0 in reply to Charles Tsai
    Prodigy 110 points

    I'm  running RealTerm at this time set to the identical parameters. This unit is to simulate GPS data (NMEA0183) for a sonar system - 4800 baud by the standard. GPS data from an external GPS works fine - the data being sent by the Launchpad is not proper. I've tried various methods of sending the data with  no improvement. I've reduced the data sent by my example above to simple strings for troubleshooting. I'm somewhat baffled at this point. Thank you for your help.

  • 0 in reply to Byron Blue
    TI__Guru**** 191886 points

    Hi,

      Can you do some experiments?

      - Can you increase the baudrate higher like 115200? Does it still fail?

      - Can you run the TivaWare uart_echo example and modify it for 4800? Does it show the same issue? The example can be found at C:\ti\TivaWare_C_Series-2.2.0.295\examples\boards\ek-tm4c1294xl\uart_echo.

  • 0 in reply to Charles Tsai
    Prodigy 110 points

    Thanks Charles

    I have to restart this laptop before trying - RAM is only 12GB so life becomes a burden. I will attempt these experiments. Loading and running uart_echo may be a bit of a challenge as I haven't tried running the examples in a number of years. I will get back to here after I have come back to life....

    Byron

  • 0 in reply to Charles Tsai
    Prodigy 110 points

    I've switched the baudrate to 115200. Same result.

    The code easily sends hex data to our processor as commands (e.g. - unsigned char TrxBuffer[ 5][ SIZE_OF_TRANSMIT] =
    {
    {
    0x00, 0x00, 0x00, 0x00, MODE, OMNI_MODE, TEST_ENABLE_HDR, 0x00, POSITIVE_RING_PATTERN_HDR, 0x00, NEGATIVE_RING_PATTERN_HDR, 0x00,
    SHADING_CONTROL_HDR, SHADING_OFF, RECEIVE_TILT, ZERO_TILT,...

    I've used this for a few years now without issue.

    But does not want to send ASCII text (e.g. - char rmcArray [320][ 100] =
    {
    "$GPRMC,152452.530,A,4508.675,N,07505.073,W,007.8,025.2,191023,000.0,W*67",...

    The problem appears to be handling ASCII characters. Is there a configuration point I've missed?

    I'm still trying to load the uart_echo project.

    Thank you lad,

    Byron

  • 0 in reply to Byron Blue
    Prodigy 110 points

    I have found the issue!

    Apparently the data leaving the TI board is the wrong polarity? I added a single transistor to invert the signal.

    I'm now wondering why the transmission of hex data for years has worked fine...

    Thank you again Charles. I was at my wits end ;)

    Byron