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Products => Arduino Due => Topic started by: gennarocuccovillo on Mar 04, 2013, 11:19 am

Title: Arduino DUE Clock Frequency and PLL configuration
Post by: gennarocuccovillo on Mar 04, 2013, 11:19 am
Hello everybody.
I have a little "simple" question for all the guests:
I noted that to get up and get down a general digital line on ARDUINO DUE need a time of about 2.5 microsecs, using the digitlaWrite() function. So my questions is: Are we sure that the clock frequency of the board is 86 MHz? Which is the proof?
In addiction I need to know if there are any possibilities to access directly to the PLL register of the microcontroller to set the clock frequency at the maximum rate.
Thank to all in advance
Title: Re: Arduino DUE Clock Frequency and PLL configuration
Post by: stimmer on Mar 04, 2013, 11:57 am
It's 84MHz. For evidence of this I've attached the output of GNU Radio on RTLSDR with an aerial right next to the Due - you can clearly see a strong signal at 84MHz.

For faster digitalWrite(), search the forum for digitalWriteDirect - here's one thread: http://arduino.cc/forum/index.php/topic,133884.0.html
Title: Re: Arduino DUE Clock Frequency and PLL configuration
Post by: gennarocuccovillo on Mar 04, 2013, 02:23 pm
thank you very much
I just tried to blink the led line directly via set and clear the PIOB (line 27).
Resul: get up and get down in 35 Mhz