170 lines
4.7 KiB
C++
170 lines
4.7 KiB
C++
// ws2812_lib.cpp
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//
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// main library file / contains class implementation
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//
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// Need to give credits to Charles Lohr (https://github.com/cnlohr due
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// to his work on his software for driving ws2812 led-strips using
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// the i2s interface of the ESP8266.
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//
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// This inspired me to create an ESP8266 library for the Arduino IDE
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// I've added temporal dithering & gamma-correction
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// for a 'more natural' light intensity profile.
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//
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// No pin-definitions/mapings are required/possible as the library used the I2S
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// output-pin. This pin in it's turn is shared with GPIO3 & RXD0
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//
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#include <Arduino.h>
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#include <stdint.h>
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#include "ws2812_i2s.h"
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#include "ws2812_defs.h"
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#include "ws2812_gamma.h"
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// include C-style header
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extern "C"
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{
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#include "ws2812_dma.h"
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};
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// class constructor
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WS2812::WS2812(void)
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{
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// empty for now
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}
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// class de-constructor
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WS2812::~WS2812(void)
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{
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// empty for now
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// TODO : should implement switching of DMA
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}
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// Init led-string / memory buffers etc.
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void WS2812::init(uint16_t _num_leds)
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{
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uint8_t i;
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uint16_t j;
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num_leds = _num_leds;
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// clear zero buffer
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for(j=0; j<NUM_I2S_ZERO_WORDS; j++)
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{
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i2s_zeros_buffer[j] = 0;
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}
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// do memory allocation for i2s buffer(s)
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for(i=0; i<WS2812_DITHER_NUM; i++)
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{
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i2s_pixels_buffer[i] = new uint32_t[NUM_I2S_PIXEL_WORDS];
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// TODO : handle memory allocation error better
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if (i2s_pixels_buffer[i] == 0)
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{
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Serial.println("WS2812_I2S : ERROR ALLOCATING MEMORY");
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return;
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}
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for(j=0; j<NUM_I2S_PIXEL_WORDS; j++)
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{
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i2s_pixels_buffer[i][j] = 0;
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}
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}
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// set-up DMA descriptors / 1 pair per dither-factor
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for(i=0; i<WS2812_DITHER_NUM; i++)
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{
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i2s_pixels_queue[i].owner = 1;
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i2s_pixels_queue[i].eof = 1;
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i2s_pixels_queue[i].sub_sof = 0;
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i2s_pixels_queue[i].datalen = NUM_I2S_PIXEL_BYTES; // Size in bytes
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i2s_pixels_queue[i].blocksize = NUM_I2S_PIXEL_BYTES; // Size in bytes
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i2s_pixels_queue[i].buf_ptr = (uint32_t)i2s_pixels_buffer[i];
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i2s_pixels_queue[i].unused = 0;
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i2s_pixels_queue[i].next_link_ptr = (uint32_t)&i2s_zeros_queue[i]; // always link to zeros-buffer
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i2s_zeros_queue[i].owner = 1;
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i2s_zeros_queue[i].eof = 1;
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i2s_zeros_queue[i].sub_sof = 0;
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i2s_zeros_queue[i].datalen = NUM_I2S_ZERO_BYTES; // Size in bytes)
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i2s_zeros_queue[i].blocksize = NUM_I2S_ZERO_BYTES; // Size in bytes
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i2s_zeros_queue[i].buf_ptr = (uint32_t)i2s_zeros_buffer;
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i2s_zeros_queue[i].unused = 0;
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if (i == (WS2812_DITHER_NUM-1)) // last DMA descriptor in linked list ?
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{
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// yes : link to first DMA descriptor
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i2s_zeros_queue[i].next_link_ptr = (uint32_t)&i2s_pixels_queue[0];
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}
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else
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{
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// no : link to next DMA descriptor
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i2s_zeros_queue[i].next_link_ptr = (uint32_t)&i2s_pixels_queue[i+1];
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}
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}
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// call C based helper function
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// I did not really succeed in putting the code from the helper
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// funtion directly into this constructor...has something to do
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// with C vs. C++
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// the i2c_writeReg_Mask macro (+ others) failed.. see ws2812_defs.h
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// may be I solve this later
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// parameter = first entry in DMA descriptor list, i.e the descriptor list
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ws2812_dma(i2s_pixels_queue);
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}
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// left this comment in tact....credit to Charles
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// All functions below this line are Public Domain 2015 Charles Lohr.
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// this code may be used by anyone in any way without restriction or limitation.
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// Send out WS2812 bits with coded pulses, one nibble, then the other.
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static const uint16_t bitpatterns[16] =
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{
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0b1000100010001000, 0b1000100010001110, 0b1000100011101000, 0b1000100011101110,
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0b1000111010001000, 0b1000111010001110, 0b1000111011101000, 0b1000111011101110,
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0b1110100010001000, 0b1110100010001110, 0b1110100011101000, 0b1110100011101110,
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0b1110111010001000, 0b1110111010001110, 0b1110111011101000, 0b1110111011101110,
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};
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// display the pixels
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void WS2812::show(Pixel_t *pixels)
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{
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uint8_t *buffer;
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uint8_t pixelbyte;
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uint8_t gammabyte;
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uint16_t i,b;
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uint16_t *i2s_ptr[WS2812_DITHER_NUM];
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buffer = (uint8_t *)pixels;
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// set-up pointers into the i2s-pixel-buffers
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for(i=0; i<WS2812_DITHER_NUM; i++)
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{
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i2s_ptr[i] = (uint16_t *)i2s_pixels_buffer[i];
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}
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// for every pixel in the input-array
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// - get the pixel value (either R,G, or B)
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// - for every dithered buffer
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// get the gamma-corrected output value
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// - and transform into i2s nibble
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for(b=0; b<NUM_RGB_BYTES; b++)
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{
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pixelbyte = *buffer++;
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for(i=0; i<WS2812_DITHER_NUM; i++)
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{
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gammabyte = gamma_dither[i][pixelbyte];
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*(i2s_ptr[i]++) = bitpatterns[ (gammabyte & 0x0f) ];
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*(i2s_ptr[i]++) = bitpatterns[ (gammabyte>>4) & 0x0f ];
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}
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}
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}
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// end of file
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