88 lines
3.2 KiB
C
88 lines
3.2 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2016 Scott Shawcroft for Adafruit Industries
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "mphalport.h"
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#include "shared-bindings/neopixel_write/__init__.h"
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#include "asf/common2/services/delay/delay.h"
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#include "asf/sam0/drivers/port/port.h"
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void common_hal_neopixel_write(const digitalio_digitalinout_obj_t* digitalinout, uint8_t *pixels, uint32_t numBytes) {
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// This is adapted directly from the Adafruit NeoPixel library SAMD21G18A code:
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// https://github.com/adafruit/Adafruit_NeoPixel/blob/master/Adafruit_NeoPixel.cpp
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uint8_t *ptr, *end, p, bitMask;
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uint32_t pinMask;
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PortGroup* port;
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// Turn off interrupts of any kind during timing-sensitive code.
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mp_hal_disable_all_interrupts();
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// Make sure the NVM cache is consistently timed.
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NVMCTRL->CTRLB.bit.READMODE = NVMCTRL_CTRLB_READMODE_DETERMINISTIC_Val;
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uint32_t pin = digitalinout->pin->pin;
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port = port_get_group_from_gpio_pin(pin);
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pinMask = (1UL << (pin % 32)); // From port_pin_set_output_level ASF code.
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ptr = pixels;
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end = ptr + numBytes;
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p = *ptr++;
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bitMask = 0x80;
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volatile uint32_t *set = &(port->OUTSET.reg),
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*clr = &(port->OUTCLR.reg);
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for(;;) {
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*set = pinMask;
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asm("nop; nop;");
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if(p & bitMask) {
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asm("nop; nop; nop; nop; nop; nop; nop;");
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*clr = pinMask;
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} else {
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*clr = pinMask;
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asm("nop; nop;");
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}
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if((bitMask >>= 1) != 0) {
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asm("nop; nop; nop; nop; nop;");
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} else {
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if(ptr >= end) break;
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p = *ptr++;
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bitMask = 0x80;
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}
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}
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// Speed up! (But inconsistent timing.)
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NVMCTRL->CTRLB.bit.READMODE = NVMCTRL_CTRLB_READMODE_NO_MISS_PENALTY_Val;
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// Turn on interrupts after timing-sensitive code.
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mp_hal_enable_all_interrupts();
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// 50us delay to let pixels latch to the data that was just sent.
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// This could be optimized to only occur before pixel writes when necessary,
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// like in the Arduino library.
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delay_us(50);
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}
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