I have a question about the clock of SAMB11. I have the SAMB11 Xplained board and works fine with the Atmel examples, like the blinking example.
I have also designed a circuit board with a separate SAMB11 chip and when I program this chip with the same example software, there' s a problem with timing.
When I program a delay of 200 ms and use the program at the Xplained board, the output is toggled every 200 ms. But with the same program on my own circuit board it is about 240 ms. The time is not constant and varies with addition of extra software.
I have measured the frequency of the crystal on my board and it is exactly 26 MHz with a spectrum analyzer, so that's not the problem.
I used the reference diagram of the SAMB11 datasheet for the design. The only difference is that I don' t use a RTC clock, because I don' t need this for my application. Also the baudrate of the UART differs from the XPlained board, so it seems it is working at the internal RC oscillator?
Does someone recognize this, what is wrong?