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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2016 Scott Shawcroft for Adafruit Industries
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "mphalport.h"
#include "shared-bindings/neopixel_write/__init__.h"
#include "asf/common2/services/delay/delay.h"
void common_hal_neopixel_write(const nativeio_digitalinout_obj_t* digitalinout, uint8_t *pixels, uint32_t numBytes) {
// This is adapted directly from the Adafruit NeoPixel library SAMD21G18A code:
// https://github.com/adafruit/Adafruit_NeoPixel/blob/master/Adafruit_NeoPixel.cpp
uint8_t *ptr, *end, p, bitMask;
uint32_t pinMask;
PortGroup* port;
// Turn off interrupts of any kind during timing-sensitive code.
mp_hal_disable_all_interrupts();
// Make sure the NVM cache is consistently timed.
NVMCTRL->CTRLB.bit.READMODE = NVMCTRL_CTRLB_READMODE_DETERMINISTIC_Val;
uint32_t pin = digitalinout->pin->pin;
port = port_get_group_from_gpio_pin(pin);
pinMask = (1UL << (pin % 32)); // From port_pin_set_output_level ASF code.
ptr = pixels;
end = ptr + numBytes;
p = *ptr++;
bitMask = 0x80;
volatile uint32_t *set = &(port->OUTSET.reg),
*clr = &(port->OUTCLR.reg);
for(;;) {
*set = pinMask;
asm("nop; nop;");
if(p & bitMask) {
asm("nop; nop; nop; nop; nop; nop; nop;");
*clr = pinMask;
} else {
*clr = pinMask;
asm("nop; nop;");
}
if((bitMask >>= 1) != 0) {
asm("nop; nop; nop; nop; nop;");
} else {
if(ptr >= end) break;
p = *ptr++;
bitMask = 0x80;
}
}
// Speed up! (But inconsistent timing.)
NVMCTRL->CTRLB.bit.READMODE = NVMCTRL_CTRLB_READMODE_NO_MISS_PENALTY_Val;
// Turn on interrupts after timing-sensitive code.
mp_hal_enable_all_interrupts();
// 50us delay to let pixels latch to the data that was just sent.
// This could be optimized to only occur before pixel writes when necessary,
// like in the Arduino library.
delay_us(50);
}
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