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[example] Add Feather M4 neopixel example
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/* | ||
* Copyright (c) 2016-2017, Niklas Hauser | ||
* Copyright (c) 2023, Thomas Rush | ||
* | ||
* This file is part of the modm project. | ||
* | ||
* This Source Code Form is subject to the terms of the Mozilla Public | ||
* License, v. 2.0. If a copy of the MPL was not distributed with this | ||
* file, You can obtain one at http://mozilla.org/MPL/2.0/. | ||
*/ | ||
// ---------------------------------------------------------------------------- | ||
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#include <modm/board.hpp> | ||
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using namespace Board; | ||
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/* | ||
* Output a color (GRB) to the Neopixel | ||
* | ||
* 'Neopixel' is Adafruit's name for what is essentially a WS2812 RGB LED. | ||
* The timing, which runs at 800kHz, is basically a long high pulse followed | ||
* by a short low pulse for a '1' bit, or a short high pulse followed by a | ||
* long low pulse for a '0' bit. The idle state of the signal is low. The | ||
* data is 24 bits long (three 8-bit color values sent out in green-red-blue | ||
* order, MSB first). | ||
* | ||
* The long and short pulse times chosen here are nominally 875ns and 375ns, | ||
* respectively, totalling 1.25us per bit. Using modm::delay_ns() with these | ||
* values means that the actual times will be slightly longer because of the | ||
* setup times for each bit, but the cycle time can be longer (within limits) | ||
* without affecting the operation. (See | ||
* https://cpldcpu.wordpress.com/2014/01/14/light_ws2812-library-v2-0-part-i-understanding-the-ws2812/ | ||
* for more information about the signal timing for these devices.) | ||
* | ||
* This function is not intended to be the best solution as a driver for the | ||
* WS2812, just an example of a simple application of the modm library. | ||
*/ | ||
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void | ||
setPixel(uint32_t data) | ||
{ | ||
constexpr uint32_t neoPeriod = 1250; | ||
constexpr uint32_t neoOneHi = 875; | ||
constexpr uint32_t neoZeroHi = 375; | ||
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uint32_t bitMask = (1UL << 23); | ||
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{ | ||
modm::atomic::Lock lock; | ||
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do | ||
{ | ||
uint32_t hiTime = data & bitMask ? neoOneHi : neoZeroHi; | ||
Neopixel::toggle(); // toggle high | ||
modm::delay_ns(hiTime); | ||
Neopixel::toggle(); // toggle low | ||
modm::delay_ns(neoPeriod - hiTime); | ||
bitMask >>= 1; | ||
} | ||
while (bitMask); | ||
} | ||
} | ||
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int | ||
main() | ||
{ | ||
initialize(); | ||
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// Use the logging streams to print some messages. | ||
// Change MODM_LOG_LEVEL above to enable or disable these messages | ||
MODM_LOG_DEBUG << "debug" << modm::endl; | ||
MODM_LOG_INFO << "info" << modm::endl; | ||
MODM_LOG_WARNING << "warning" << modm::endl; | ||
MODM_LOG_ERROR << "error" << modm::endl; | ||
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uint32_t counter(0); | ||
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const char *log_str[] = { "green ", "red ", "blue ", "loop: " }; | ||
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while (true) | ||
{ | ||
// color values are reduced to decrease the brightness of the LED | ||
// (full intensity can be uncomfortable for the eyes!) | ||
for (uint32_t i = 0, color = 0x110000; i < 4; i++, color >>= 8) { | ||
modm::delay(1s); | ||
setPixel(color); | ||
MODM_LOG_INFO << log_str[i]; | ||
} | ||
MODM_LOG_INFO << counter++ << modm::endl; | ||
} | ||
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return 0; | ||
} | ||
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<library> | ||
<extends>modm:feather-m4</extends> | ||
<options> | ||
<option name="modm:build:build.path">../../../build/feather_m4/neopixel</option> | ||
</options> | ||
<modules> | ||
<module>modm:build:scons</module> | ||
<module>modm:architecture:delay</module> | ||
</modules> | ||
</library> |