• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 53 subscribers
  • Views 545 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Random Resets with CC1111 USB Dongle

David Eisner
Intellectual 310 points

I'm having a strange problem with a program for the CC1111 USB dongle: My program randomly reboots, sometimes after a few tens of minutes, sometimes after many hours.  I'm relatively new to embedded systems, so I might be making a rookie mistake.

I'm working on a breadboard prototype -- the dongle is wired up to a digital temperature sensor and a digital accelerometer via an SPI bus.  I'm using IAR EW8051 8.10.3.

I had been communicating with my program using serialport-over-USB, and thought perhaps the PC was responsible.  So I've removed that from the equation -- I have the dongle connected to a USB cable plugged into a powerstrip surge protector with a USB port.  All feedback now happens through the LED.

At the beginning of main() I check the SLEEP register to see the reason for the last reset, and set an LED blink pattern accordingly:

 

int main( void )

{  

    uint8 reset_cause = (SLEEP & SLEEP_RST) >> 3;

    if (reset_cause == 0)

        led_pattern = POWER_RESET_PTRN;

    else if (reset_cause == 1)

        led_pattern = EXT_RESET_PTRN;

    else if (reset_cause == 2)

        led_pattern = WATCHDOG_RESET_PTRN;

    else 

        led_pattern = ERROR_PTRN;


 

I take input from the dongle button.  On the first press, I change the LED pattern to a "default pattern" that is different from the others.  Then I wait.  Eventually, it restarts and the LED pattern tells me that the last reset cause was an external reset.  I can also produce this by sticking a paper clip or wire in the ribbon cable connected to the debug connector (pin 7).

If the button is pressed a second time, the program begins a ten second countdown and then calls halMcuReset(), which uses the watchdog timer to reset the uC. Ten seconds later, I see the WATCHDOG_RESET_PTRN I expect.

One weird thing is that if I disconnect the dongle from the USB cable (so no power), wait, and reconnect it, the LED pattern shows the EXT_RESET_PTRN, and not the POWER_RESET_PTRN.  This is making it impossible to determine whether power is the problem. When the dongle was still connected to the PC, I do believe I saw the POWER_RESET_PTRN at least once.

Any idea what could be causing this?  Can I trust SLEEP.RST?  

Thanks!

-David

 

 

 

 

 

 

  • 0
    Intellectual 310 points

    To answer my own question, it looks like noise on the RESET pin is probably the culprit.  According to the datasheet, "The RESET_N pin is sensitive to noise and can cause unintended reset of the chip."  I assumed the USB dongle design took this into account, but perhaps not.

     

    What I found is that if the the debug ribbon cable is connected to the USB dongle debug port (whether or not the other end is connected to the SoC Debug Plug-in module), the uC will reset itself after some time (after tens of minutes up to tens of hours) .  However, if I disconnect the cable from the port, the system does not reset (or at least not after 5+ days in my last test).

     

    -David