mirror of
https://github.com/Hopiu/rpi-rgb-led-matrix.git
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119 lines
4.3 KiB
C++
119 lines
4.3 KiB
C++
// -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
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// Copyright (C) 2013 Henner Zeller <h.zeller@acm.org>
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//
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation version 2.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://gnu.org/licenses/gpl-2.0.txt>
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// Controlling a 32x32 RGB matrix via GPIO.
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#ifndef RPI_RGBMATRIX_H
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#define RPI_RGBMATRIX_H
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#include <stdint.h>
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#include "gpio.h"
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#include "canvas.h"
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namespace rgb_matrix {
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// The RGB matrix provides the framebuffer and the facilities to constantly
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// update the LED matrix.
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class RGBMatrix : public Canvas {
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public:
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// Initialize RGB matrix with GPIO to write to. The "rows" are the number
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// of rows supported by the display, so 32 or 16. Number of "chained_display"s
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// tells many of these are daisy-chained together.
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// If "io" is not NULL, starts refreshing the screen immediately; you can
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// defer that by setting GPIO later with SetGPIO().
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RGBMatrix(GPIO *io, int rows = 32, int chained_displays = 1);
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virtual ~RGBMatrix();
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// Set GPIO output if it was not set already in constructor (oterwise: no-op).
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// Starts display refresh thread if this is the first setting.
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void SetGPIO(GPIO *io);
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// Set PWM bits used for output. Default is 11, but if you only deal with
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// simple comic-colors, 1 might be sufficient. Lower require less CPU.
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// Returns boolean to signify if value was within range.
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bool SetPWMBits(uint8_t value);
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uint8_t pwmbits() { return pwm_bits_; }
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// Map brightness of output linearly to input with CIE1931 profile.
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void set_luminance_correct(bool on) { do_luminance_correct_ = on; }
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bool luminance_correct() const { return do_luminance_correct_; }
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// -- Canvas interface
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virtual int width() const { return columns_; }
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virtual int height() const { return rows_; }
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virtual void SetPixel(int x, int y,
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uint8_t red, uint8_t green, uint8_t blue);
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virtual void Clear();
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virtual void Fill(uint8_t red, uint8_t green, uint8_t blue);
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private:
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class UpdateThread;
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friend class UpdateThread;
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// Updates the screen, connected to the GPIO pins, once.
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// (If you were calling this before as public method in a thread to
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// update the screen: this is not necessary anymore. The RGBMatrix does
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// this now by itself already. You can get rid of that thread. Sorry for the
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// API-change inconvenience).
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void UpdateScreen();
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// Map color
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inline uint16_t MapColor(uint8_t c);
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const int rows_; // Number of rows. 16 or 32.
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const int columns_; // Number of columns. Number of chained boards * 32.
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uint8_t pwm_bits_; // PWM bits to display.
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bool do_luminance_correct_;
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const int double_rows_;
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const uint8_t row_mask_;
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GPIO *io_;
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UpdateThread *updater_;
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union IoBits {
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struct {
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// These reflect the GPIO mapping.
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unsigned int unused1 : 2; // 0..1
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unsigned int output_enable : 1; // 2
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unsigned int clock : 1; // 3
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unsigned int strobe : 1; // 4
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unsigned int unused2 : 2; // 5..6
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unsigned int row : 4; // 7..10
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unsigned int unused3 : 6; // 11..16
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unsigned int r1 : 1; // 17
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unsigned int g1 : 1; // 18
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unsigned int unused4 : 3;
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unsigned int b1 : 1; // 22
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unsigned int r2 : 1; // 23
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unsigned int g2 : 1; // 24
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unsigned int b2 : 1; // 25
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} bits;
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uint32_t raw;
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IoBits() : raw(0) {}
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};
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// The frame-buffer is organized in bitplanes.
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// Highest level (slowest to cycle through) are double rows.
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// For each double-row, we store pwm-bits columns of a bitplane.
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// Each bitplane-column is pre-filled IoBits, of which the colors are set.
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// Of course, that means that we store unrelated bits in the frame-buffer,
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// but it allows easy access in the critical section.
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IoBits *bitplane_framebuffer_;
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inline IoBits *ValueAt(int double_row, int column, int bit);
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};
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} // end namespace rgb_matrix
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#endif // RPI_RGBMATRIX_H
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