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Diffstat (limited to 'docs/library/machine.rst')
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diff --git a/docs/library/machine.rst b/docs/library/machine.rst index 26f99680a..c2a6b3900 100644 --- a/docs/library/machine.rst +++ b/docs/library/machine.rst @@ -137,6 +137,28 @@ Miscellaneous functions above. The timeout is the same for both cases and given by *timeout_us* (which is in microseconds). +.. function:: bitstream(pin, encoding, timing, data, /) + + Transmits *data* by bit-banging the specified *pin*. The *encoding* argument + specifies how the bits are encoded, and *timing* is an encoding-specific timing + specification. + + The supported encodings are: + + - ``0`` for "high low" pulse duration modulation. This will transmit 0 and + 1 bits as timed pulses, starting with the most significant bit. + The *timing* must be a four-tuple of nanoseconds in the format + ``(high_time_0, low_time_0, high_time_1, low_time_1)``. For example, + ``(400, 850, 800, 450)`` is the timing specification for WS2812 RGB LEDs + at 800kHz. + + The accuracy of the timing varies between ports. On Cortex M0 at 48MHz, it is + at best +/- 120ns, however on faster MCUs (ESP8266, ESP32, STM32, Pyboard), it + will be closer to +/-30ns. + + .. note:: For controlling WS2812 / NeoPixel strips, see the :mod:`neopixel` + module for a higher-level API. + .. function:: rng() Return a 24-bit software generated random number. |