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Ignat99 edited this page Nov 2, 2014 · 30 revisions

GPIO (General Purpose Input Output)

The python software cycles through digital GPIO pins made ​​with a maximum frequency of ~ 27 kHz. In each of the stable states ("1" and "0") is output may for about 18-20 microseconds. Get a shorter duration pulses using used paper software is impossible.

GPIO pin switching time from one state to another (in other words the length of the transition process) - it is about 50 ns. I must say, quite good results, however, and compete in speed with the FPGA GPIO Raspberry Pi can not.

GPIO pins, which operate in the mode of serial interfaces, can achieve high speeds, since the serial interface at high speed processor hardware generates clock frequencies and signals according to the rules of a serial interface. For example, using O GPCLK0 possible to obtain a pulse frequency of 100 MHz and above.

The C software cycles through digital GPIO pins have minimum pulse duration - 100 ns, the switching frequency - 5 MHz! Compared with Python'om C yielded approximately 185-fold the speed boost.

See also

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