The LED on pin 13 always being on doesn't necessarily indicate any problem at all. You may just have uploaded a sketch to your board that turns the LED on.Please provide a detailed description of the problem you're having.
Stop doing whatever is making it reset.Could bd the sketch - writing off thed end of an array usually causes it to reset.The board resets when you open serial monitor (or most other serial consoles) - if this is a problem, put a 10uF cap between reset and ground after uploading sketch; you must remove it to upload new code.Excessive load on power can cause resets.
Will I connect - of cap to gnd and + of cap to reset?
It is not problem with that. I try to test mpu6050 and led on pin 13 is always on. This test example is from electronoobs page. In code there isn't command that turn led 13 on.
Pin13 is also the SCK pin, so when SPI is in use, it will flicker when SPI is actively transferring data, and stay on (or off depending on the SPI mode used) when not transferring data.
Ok. Thanks I forget this. I used nrf24 on atmega328 as arduino on beadboard and on arduino uno, on uno led 13 doesn't blink on atmaga328 blink, and radio communication doesn't work. Do you know why?