219 lines
9.1 KiB
C++
219 lines
9.1 KiB
C++
#ifndef LEDDEVICEWS2812B_H_
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#define LEDDEVICEWS2812B_H_
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#pragma once
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// Set tabs to 4 spaces.
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// =================================================================================================
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//
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// __ __ _________________ ______ ____________ ____________________.__
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// / \ / \/ _____/\_____ \ / __ \/_ \_____ \ \______ \______ \__|
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// \ \/\/ /\_____ \ / ____/ > < | |/ ____/ | _/| ___/ |
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// \ / / \/ \/ -- \| / \ | | \| | | |
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// \__/\ / /_______ /\_______ \______ /|___\_______ \ |____|_ /|____| |__|
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// \/ \/ \/ \/ \/ \/
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//
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// WS2812 NeoPixel driver
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// Based on code by Richard G. Hirst and others
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// Adapted for the WS2812 by 626Pilot, April/May 2014
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// See: https://github.com/626Pilot/RaspberryPi-NeoPixel-WS2812
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// Version: https://github.com/626Pilot/RaspberryPi-NeoPixel-WS2812/blob/1d43407d9e6eba19bff24330bc09a27963b55751/ws2812-RPi.c
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// Huge ASCII art section labels are from http://patorjk.com/software/taag/
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//
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// LED driver adaptation by Kammerjaeger ()
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// mostly code removed that was not needed
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//
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// License: GPL
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//
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// You are using this at your OWN RISK. I believe this software is reasonably safe to use (aside
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// from the intrinsic risk to those who are photosensitive - see below), although I can't be certain
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// that it won't trash your hardware or cause property damage.
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//
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// Speaking of risk, WS2812 pixels are bright enough to cause eye pain and (for all I know) possibly
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// retina damage when run at full strength. It's a good idea to set the brightness at 0.2 or so for
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// direct viewing (whether you're looking directly at the pixels or not), or to put some diffuse
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// material between you and the LEDs.
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//
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// PHOTOSENSITIVITY WARNING:
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// Patterns of light and darkness (stationary or moving), flashing lights, patterns and backgrounds
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// on screens, and the like, may cause epilleptic seizures in some people. This is a danger EVEN IF
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// THE PERSON (WHICH MAY BE *YOU*) HAS NEVER KNOWINGLY HAD A PHOTOSENSITIVE EPISODE BEFORE. It's up
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// to you to learn the warning signs, but symptoms may include dizziness, nausea, vision changes,
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// convlusions, disorientation, involuntary movements, and eye twitching. (This list is not
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// necessarily exhaustive.)
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//
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// NEOPIXEL BEST PRACTICES: https://learn.adafruit.com/adafruit-neopixel-uberguide/best-practices
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//
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// Connections:
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// Positive to Raspberry Pi's 3.3v, for better separation connect only ground and data directly
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// (5v can be used then without a problem, at least it worked for me, Kammerjaeger)
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// Negative to Raspberry Pi's ground
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// Data to GPIO18 (Pin 12) (through a resistor, which you should know from the Best
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// Practices guide!)
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//
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// Buy WS2812-based stuff from: http://adafruit.com
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//
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// To activate: use led device "ws2812s" in the hyperion configuration
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// (it needs to be root so it can map the peripherals' registers)
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//
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// =================================================================================================
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// This is for the WS2812 LEDs. It won't work with the older WS2811s, although it could be modified
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// for that without too much trouble. Preliminary driver used Frank Buss' servo driver, but I moved
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// to Richard Hirst's memory mapping/access model because his code already works with DMA, and has
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// what I think is a slightly cleaner way of accessing the registers: register[name] rather than
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// *(register + name).
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// At the time of writing, there's a lot of confusing "PWM DMA" code revolving around simulating
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// an FM signal. Usually this is done without properly initializing certain registers, which is
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// OK for their purpose, but I needed to be able to transfer actual coherent data and have it wind
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// up in a proper state once it was transferred. This has proven to be a somewhat painful task.
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// The PWM controller likes to ignore the RPTL1 bit when the data is in a regular, repeating
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// pattern. I'M NOT MAKING IT UP! It really does that. It's bizarre. There are lots of other
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// strange irregularities as well, which had to be figured out through trial and error. It doesn't
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// help that the BCM2835 ARM Peripherals manual contains outright errors and omissions!
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// Many examples of this kind of code have magic numbers in them. If you don't know, a magic number
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// is one that either lacks an obvious structure (e.g. 0x2020C000) or purpose. Please don't use
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// that stuff in any code you release! All magic numbers found in reference code have been changed
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// to DEFINEs. That way, instead of seeing some inscrutable number, you see (e.g.) PWM_CTL.
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// References - BCM2835 ARM Peripherals:
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// http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf
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//
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// Raspberry Pi low-level peripherals:
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// http://elinux.org/RPi_Low-level_peripherals
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//
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// Richard Hirst's nice, clean code:
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// https://github.com/richardghirst/PiBits/blob/master/PiFmDma/PiFmDma.c
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//
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// PWM clock register:
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// http://www.raspberrypi.org/forums/viewtopic.php?t=8467&p=124620
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//
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// Simple (because it's in assembly) PWM+DMA setup:
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// https://github.com/mikedurso/rpi-projects/blob/master/asm-nyancat/rpi-nyancat.s
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//
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// Adafruit's NeoPixel driver:
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// https://github.com/adafruit/Adafruit_NeoPixel/blob/master/Adafruit_NeoPixel.cpp
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// Hyperion includes
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#include <leddevice/LedDevice.h>
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//#define BENCHMARK
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#define WS2812_ASM_OPTI
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// The page map contains pointers to memory that we will allocate below. It uses two pointers
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// per address. This is because the software (this program) deals only in virtual addresses,
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// whereas the DMA controller can only access RAM via physical address. (If that's not confusing
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// enough, it writes to peripherals by their bus addresses.)
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struct page_map_t
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{
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uint8_t *virtaddr;
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uint32_t physaddr;
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};
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// Control Block (CB) - this tells the DMA controller what to do.
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struct dma_cb_t
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{
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unsigned info; // Transfer Information (TI)
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unsigned src; // Source address (physical)
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unsigned dst; // Destination address (bus)
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unsigned length; // Length in bytes (not words!)
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unsigned stride; // We don't care about this
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unsigned next; // Pointer to next control block
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unsigned pad[2]; // These are "reserved" (unused)
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};
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///
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/// Implementation of the LedDevice interface for writing to Ws2801 led device.
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///
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class LedDeviceWS2812b : public LedDevice
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{
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public:
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///
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/// Constructs the LedDevice for a string containing leds of the type WS2812
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LedDeviceWS2812b();
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~LedDeviceWS2812b();
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///
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/// Writes the led color values to the led-device
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///
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/// @param ledValues The color-value per led
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/// @return Zero on succes else negative
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///
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virtual int write(const std::vector<ColorRgb> &ledValues);
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/// Switch the leds off
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virtual int switchOff();
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private:
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/// the number of leds (needed when switching off)
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size_t mLedCount;
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page_map_t *page_map; // This will hold the page map, which we'll allocate
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uint8_t *virtbase; // Pointer to some virtual memory that will be allocated
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volatile unsigned int *pwm_reg; // PWM controller register set
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volatile unsigned int *clk_reg; // PWM clock manager register set
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volatile unsigned int *dma_reg; // DMA controller register set
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volatile unsigned int *gpio_reg; // GPIO pin controller register set
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// Contains arrays of control blocks and their related samples.
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// One pixel needs 72 bits (24 bits for the color * 3 to represent them on the wire).
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// 768 words = 341.3 pixels
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// 1024 words = 455.1 pixels
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// The highest I can make this number is 1016. Any higher, and it will start copying garbage to the
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// PWM controller. I think it might be because of the virtual->physical memory mapping not being
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// contiguous, so *pointer+1016 isn't "next door" to *pointer+1017 for some weird reason.
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// However, that's still enough for 451.5 color instructions! If someone has more pixels than that
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// to control, they can figure it out. I tried Hirst's message of having one CB per word, which
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// seems like it might fix that, but I couldn't figure it out.
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#define NUM_DATA_WORDS 1016
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struct control_data_s {
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dma_cb_t cb[1];
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uint32_t sample[NUM_DATA_WORDS];
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};
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//struct control_data_s *ctl;
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// PWM waveform buffer (in words), 16 32-bit words are enough to hold 170 wire bits.
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// That's OK if we only transmit from the FIFO, but for DMA, we will use a much larger size.
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// 1024 (4096 bytes) should be enough for over 400 elements. It can be bumped up if you need more!
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unsigned int PWMWaveform[NUM_DATA_WORDS];
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void initHardware();
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void startTransfer();
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void clearPWMBuffer();
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void setPWMBit(unsigned int bitPos, unsigned char bit);
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unsigned int mem_phys_to_virt(uint32_t phys);
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unsigned int mem_virt_to_phys(void *virt);
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void terminate(int dummy);
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void fatal(const char *fmt, ...);
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void * map_peripheral(uint32_t base, uint32_t len);
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void printBinary(unsigned int i, unsigned int bits);
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#ifdef BENCHMARK
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unsigned int runCount;
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long combinedNseconds;
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long shortestNseconds;
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#endif
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};
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#endif /* LEDDEVICEWS2812B_H_ */
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