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UART not working whrn cc debugger is removed in CC2541

Raghavadeep Reddy
Prodigy 70 points
Other Parts Discussed in Thread: CC2541

Hi,

 I am using CC 2541. I want to send temperature data sensed by cc 2541 sensor tag on UART pins.I got uart sample code in  "CC2541_43_44_45_Peripherals_Software_Examples"  zip file which I downloaded from this page  http://e2e.ti.com/support/wireless_connectivity/f/155/t/278173.aspx.

I tried uart_poll.c after modifying it.I modified it so that I can use P1_4(port 1-pin4),P1_5 for Rx and Tx.I have done this  because I took UART output from P1 connector provided on the backside of battery slot on sensor tag(kindly refer schematics for P1 connector pin details).

Now the problem is that I am getting output data on uart tx pin provided if I connect cc debugger to sensor tag.If I remove it ,data from sensor tag stops which I am observing on GTK Term terminaal on linux machine.

Why should I connect CC debugger to get data from CC 2541?

  • 0
    TI__Expert 6505 points

    Can you let us know of your Pin selector & register settings? Namely, PERCFG, P0SEL, PortPRI, etc? Also Is flow Control enabled or disabled?

    Regards,

    Arun

  • 0 in reply to Arun Menon
    Prodigy 70 points

    Hi Arun,

    Firstly thanks a lot for replying.

    I am using connector P1 provided on the back side of sensor tag battery slot.

    Kindly refer the schematics of sensor tag in http://www.ti.com/lit/df/swrr126/swrr126.pdf.

    In this doc u can find P1 connector having Rx and Tx pins connected to P1_4(port1 pin 4) and P1_5.

    So I configured UART0 in alt 2.My register values are as follows:

    PERCFG=0x01;

    P1SEL |=0x3c -here  P1SEL has 0xF4 which is ORed with 0x3c;(so after doing this P1_4 and P1_5 is configured for peripheral function)

    P2SEL=0x00;

    U0CSR=0x86;

    hardware flow control disabled in U0UCR;

    It seems all these values are correct and I am getting output from UART Tx pin.But the problem is why I am getting output only when CC Debugger is connected.If I remove debugger immediately UART output stops.

    I read in this forum only that one guy had similar problem and someone replied that it might be due to ground issues.

    I am clueless regarding this issue.

    Thanks.

  • 0 in reply to Raghavadeep Reddy
    TI__Expert 6505 points

    Hi,

    You have to use P1SEL as 0x30 as Rx and Tx lines are on P1_4 P1_5.Even U0CSR has to 0x80.

    Since FLow control is disabled, please ground the CTS pin too.

    Regards,

    Arun 

  • 0 in reply to Arun Menon
    Intellectual 685 points

    Hi Arun ,

    Same sensortag I am using for UART , Normally I got output ( No problem with Receiving and Transmitting) but when it comes to Hardware flow control enabled I am not seeing any data on Serial Terminal ( Putty ).

    Below are my port configurations

    PERCFG = 0x01;
    P1SEL = 0x3C;
    P1 = 0x3C;
    P1DIR = 0x3C; 
    P2SEL = 0x20;

    Baud rate = 9600

  • 0 in reply to Kadari Rajamallaiah
    Intellectual 685 points
    Continuing for Previous post ........

    I connected sensortag RTS pin(P1_3) -> Serial cable CTS
    sensortag CTS pin (P1_4) -> Serial cable RTS