70 lines
1.7 KiB
C
70 lines
1.7 KiB
C
/**
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* Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include <stdio.h>
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#include <math.h>
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#include "pico/stdlib.h"
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#include "hardware/pio.h"
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#include "apa102.pio.h"
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#define PIN_CLK 2
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#define PIN_DIN 3
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#define N_LEDS 150
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#define SERIAL_FREQ (5 * 1000 * 1000)
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// Global brightness value 0->31
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#define BRIGHTNESS 16
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void put_start_frame(PIO pio, uint sm) {
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pio_sm_put_blocking(pio, sm, 0u);
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}
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void put_end_frame(PIO pio, uint sm) {
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pio_sm_put_blocking(pio, sm, ~0u);
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}
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void put_rgb888(PIO pio, uint sm, uint8_t r, uint8_t g, uint8_t b) {
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pio_sm_put_blocking(pio, sm,
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0x7 << 29 | // magic
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(BRIGHTNESS & 0x1f) << 24 | // global brightness parameter
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(uint32_t) b << 16 |
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(uint32_t) g << 8 |
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(uint32_t) r << 0
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);
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}
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#define TABLE_SIZE (1 << 8)
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uint8_t wave_table[TABLE_SIZE];
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int main() {
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stdio_init_all();
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PIO pio = pio0;
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uint sm = 0;
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uint offset = pio_add_program(pio, &apa102_mini_program);
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apa102_mini_program_init(pio, sm, offset, SERIAL_FREQ, PIN_CLK, PIN_DIN);
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for (int i = 0; i < TABLE_SIZE; ++i)
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wave_table[i] = powf(sinf(i * M_PI / TABLE_SIZE), 5.f) * 255;
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uint t = 0;
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while (true) {
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put_start_frame(pio, sm);
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for (int i = 0; i < N_LEDS; ++i) {
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put_rgb888(pio, sm,
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wave_table[(i + t) % TABLE_SIZE],
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wave_table[(2 * i + 3 * 2) % TABLE_SIZE],
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wave_table[(3 * i + 4 * t) % TABLE_SIZE]
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);
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}
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put_end_frame(pio, sm);
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sleep_ms(10);
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++t;
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}
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}
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