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Serial Communications to Hercules Launchpad from Linux

Daniel Chan1
Prodigy 20 points

Hi there,

I am using the Hercules Launchpad and I am able to communicate to the chip by means of serial comms. This is done on a Windows Operating System.

I would like to do  the same thing but this time is to send and receive data by means of serial communications from Linuux (Redhat). I have tried but I am not successful.

Can TI advice me on how to proceed on this.

Thanks.

Regards,

Daniel Chan

  • 0
    TI__Guru 68920 points

    Daniel,

    I don't think we can help too much with this problem but the problem should amount to having your linux box recognize the FTDI virtual com port.  Which probably means having the right driver packages installed.  I'd suggest maybe googling for FTDI drivers and linux.   Problem w. this type of support question on linux is that there are so many ways to install and configure your linux box.

    There are some helpful tips here http://processors.wiki.ti.com/index.php/Checking_Linux_Dependencies_for_CCS but I don't see RedHat just Fedora.  Still maybe that's close enough.
    There is also a dependency check script there to check for missing libraries.  Have you tried running this script?

     

  • 0 in reply to Anthony F. Seely
    Prodigy 20 points

    Hi Anthony,

    Thanks for the reply.

    I have manage to communicate to the Hercules Launchpad to Linux by hooking up the SCI pins to my PC serial port instead of using the native USB connection (which internally have to pass through the FTDI chip). Using this method, installation of the FTDI drivers will not be needed even in Linux.

    Unfortunately I have a slight problem. My set up is as follows:

    • Windows environment,  
    • Microcontroller is program to send a byte over. ( In this case 0x22h)
    • Hyper terminal is used to see the data sent.
    • electrically
      • SCI1_Rx (J1,3) hook Transmit data ( DB9, Pin 3 )
      • SCI1_Tx (J1,4) hook Receive data (DB9, Pin2)
      • GND (J3,2) hook to Ground ( DB9, pin5) 

    • Results
    • USB returns the correct result, which is 0x22h
    • The COM port where the SCI is hook onto returns 0xAEh constantly.    (Wrong value)

    I have tested the same configuration on Linux too. The ttyS0 port returns me 0xAEh instead of 0x22h. I have double check my COM port setting for both the USB and the SCI ones. all are having identical baud rates, parity etc.

    Thus I am wondering if TI can shed some light to me in this problem.

    Thanks for the help rendered.

    Regards

    Daniel Chan

      

  • 0 in reply to Daniel Chan1
    TI__Guru 68920 points

    Daniel

    If you connect the SCI to a DB9 connector you need to do this through an RS-232 line driver ie. http://www.ti.com/general/docs/lit/getliterature.tsp?genericPartNumber=trs232e&fileType=pdf

    I don't know what level your PC is driving to but it might be something like +/-5V.   These voltages are too high to connect directly to the Hercules device which has 3.3V LVCMOS IO.  You might have even damaged the Hercules device with this connection if you made it without a line driver so please be aware of this.

    The USB virtual serial port doesn't need a line driver because the USB chip also has 3.3V IO and it can interface directly to Hercules.  This is why that port is working.