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SCI communication problem with F28335

Other Parts Discussed in Thread: MAX232

HI

I am trying to communicate to a PC using SCI of F28335.I am currently using max232 IC as the RS-232 cable was not available for now.

We ran the echoback program given in control suite for F28069 with the same IC circuit by changing the SCIHBAUD to 0x01(earlier 0x0000) and SCILbaud to 0x03 (earlier 0x0103).It was succesfully done.we could see on the hyperterminal the sent and the recieve character.

But running echoback program for F28335 is'nt echoing back the value we are enetring. We changed the SCIHBAUD to SciaRegs.SCIHBAUD    =0x01 (earlier 0x0001) and SCILBAUD to 0xE7(earlier 0x00E7).I am looking for baud rate 9600.

I can enter the character but DSP does not echoback the same.

What am I missing?

thanks

Sneha

  • Hi Sneha,

    Did you check whether the baud rate set is 9600 on DSO? Transmit some data in while loop and check the baud rate of the data transmitted.

    Regards,

    Gautam

  • Hi Gautam

    Thanks for your prompt reply.

    But I am still confused.Checking baud rate on DSO?I am checking the output between Tx pin and ground.But I get nothing on DSO.And while running the program loopcount doesn't increments. it stops at line 160 as shwn in the screenshot.

    Kindly guide me.

    Thanks

    Sneha

  • Exactly, because its waiting at the receive interrupt. You need to remove all the receive routines and just have a sci transmit routine that polls data in a while loop, only then you'll be able to observe the data on dso.

    Regards,

    Gautam

  • HI Gautam

    Checked the same.I am attaching the code which i changed for the same.The baud rate is (1/104) micro-secs = 9615.

    Please suggest what changes have to be included in order to have this program running.

    1665.sci.txt
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    // TI File $Revision: /main/2 $
    // Checkin $Date: July 30, 2009 18:45:31 $
    //###########################################################################
    //
    // FILE: Example_2833xSci_Echoback.c
    //
    // TITLE: DSP2833x Device SCI Echoback.
    //
    // ASSUMPTIONS:
    //
    // This program requires the DSP2833x header files.
    // As supplied, this project is configured for "boot to SARAM" operation.
    //
    // Connect the SCI-A port to a PC via a transciever and cable.
    // The PC application 'hypterterminal' can be used to view the data
    // from the SCI and to send information to the SCI. Characters recieved
    // by the SCI port are sent back to the host.
    //
    // As supplied, this project is configured for "boot to SARAM"
    XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

    Thanks

    Sneha

  • Sneha Thakur said:

    Checked the same.I am attaching the code which i changed for the same.The baud rate is (1/104) micro-secs = 9615.

    Please suggest what changes have to be included in order to have this program running.

    Before doing this, I would like you to check the same with the other controller. Same transmission in a while loop... preferably same data and then compare the waveforms. The baudrate should match for the communication to happen.

    Regards,

    Gautam

  • Oki gautam I will check it for F28069 and reply in a while.

    But What if want to implement the echoback program for one controller.Its not running with  F28335.

    on the hyperterminal it asks to input the character, but after that  nothing happens.

    thanks

    Sneha

  • Hi Gautam

    I checked the waveforms for F28069 control stick.It's programmed for 9600 baud rate with LSPCLK = 20 MHz.

    The baud rate and waveforms are similar for both f28335 and f28069

    Please find attached the waveform and the program.

    7230.sci28069.txt
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    // TI File $Revision: /main/2 $
    // Checkin $Date: January 4, 2011 10:03:22 $
    //###########################################################################
    //
    // FILE: Example_2806xSci_Echoback.c
    //
    // TITLE: F2806x Device SCI Echoback.
    //
    // ASSUMPTIONS:
    //
    // This program requires the F2806x header files.
    // As supplied, this project is configured for "boot to SARAM" operation.
    //
    // Connect the SCI-A port to a PC via a transciever and cable.
    // The PC application 'hypterterminal' can be used to view the data
    // from the SCI and to send information to the SCI. Characters recieved
    // by the SCI port are sent back to the host.
    //
    // As supplied, this project is configured for "boot to SARAM"
    XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

    Please let me know how to move ahead with communication between these two controllers?

    How to change the LSPCLK value?

    How to establish echoback program with F28335 as asked in my previous post.

    Thanks

    Sneha

  • Sneha Thakur said:
    Please let me know how to move ahead with communication between these two controllers?

    Now that the  baud rates are matching... ! We're good to go ahead. You can use the same transmission code on one end and receive interrupt on the other side. Transmission controller will not require any debugging, instead you can debug the receiver and check the SCI global variables for the received data. Don't send data continuously in a while loop... instead send one at a time in short every reset should send one data that you should be able to observe on debug window.

    Regards,

    Gautam

  • Hi Gautam

    Thanks for the reply.

    Will get back to you soon.let me first make an attempt .

    Thanks

    Sneha

  • Hi 

    I am not able to communicate with F28335 using SCI.I am running the SCI_Echoback program from control suite fo r F28335.But its not working.

    The same program worked successfully for F28069 control stick.

    I am attaching the screenshot of hyperterminal screen and the watch window.the loopcount does not increments and stucks at the line waiting for recieve interrupt.

    The baud rate is 9600 set as 0001,00E7 for SCIHBAUD,SCILBAUD for LSPCLK 37.5 MHz.

    Kindly help

    Thank

    Sneha

  • Hi Sneha,

    I hope you're connecting the RX, TX and GND pins too.

    Regards,

    Gautam

  • Hi gautam

    I wasn't connecting the ground pin.

    With F28069 I just connected Tx and Rx pins to FT232RL IC circuits Rx and Tx pins and it worked successfully.

    But It is not working for F28335.I tried by connecteing the ground pins together too,but the same resukt.

    Please suggest.

    Thanks

    Sneha

  • Hi Gautam

    The problem is resolved,without connecting the ground pins.

    I changes the GPIO pins.Earlier I was checking on GPIO 28 and 29 SCIA and itdidnot run.

    By chnaging it to SCIB i.e. GPIO18 and 19 It worked.

    Thanks for all your support.

    Kindly help me with communication between two controllers as posted in the other forum.

    http://e2e.ti.com/support/microcontrollers/c2000/f/171/p/378316/1332928.aspx#1332928

    Thanks

    Sneha

  • That's Great, Sneha! but....

    Sneha Thakur said:
    The problem is resolved,without connecting the ground pins.

    Ground pin is a must when you go for custom boards where power supplies might be different. For now as the power supply is same for both you're able to observe the communication.

    Goodluck & Regards,

    Gautam

  • Oh thanks Guatam.

    I will keep that in mind.And does it concludes that GPIO28 Rx pin is not working. As I couldn't establish communication with that?

    Thanks

    Sneha

  • Sneha Thakur said:
    And does it concludes that GPIO28 Rx pin is not working. As I couldn't establish communication with that?

    Actually it should work, I guess some miss-configuration else it should've worked!

    Regards,

    Gautam

  • Thanks Gautam