325 lines
9.9 KiB
C
325 lines
9.9 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 <stdlib.h>
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#include <string.h>
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#include "pico/stdlib.h"
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#include "pico/sem.h"
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#include "hardware/pio.h"
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#include "hardware/dma.h"
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#include "hardware/irq.h"
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#include "ws2812.pio.h"
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#define FRAC_BITS 4
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#define PIN_TX 0
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// horrible temporary hack to avoid changing pattern code
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static uint8_t *current_string_out;
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static bool current_string_4color;
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static inline void put_pixel(uint32_t pixel_grb) {
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*current_string_out++ = pixel_grb & 0xffu;
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*current_string_out++ = (pixel_grb >> 8u) & 0xffu;
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*current_string_out++ = (pixel_grb >> 16u) & 0xffu;
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if (current_string_4color) {
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*current_string_out++ = 0; // todo adjust?
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}
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}
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static inline uint32_t urgb_u32(uint8_t r, uint8_t g, uint8_t b) {
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return
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((uint32_t) (r) << 8) |
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((uint32_t) (g) << 16) |
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(uint32_t) (b);
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}
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void pattern_snakes(uint len, uint t) {
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for (uint i = 0; i < len; ++i) {
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uint x = (i + (t >> 1)) % 64;
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if (x < 10)
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put_pixel(urgb_u32(0xff, 0, 0));
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else if (x >= 15 && x < 25)
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put_pixel(urgb_u32(0, 0xff, 0));
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else if (x >= 30 && x < 40)
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put_pixel(urgb_u32(0, 0, 0xff));
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else
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put_pixel(0);
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}
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}
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void pattern_random(uint len, uint t) {
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if (t % 8)
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return;
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for (int i = 0; i < len; ++i)
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put_pixel(rand());
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}
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void pattern_sparkle(uint len, uint t) {
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if (t % 8)
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return;
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for (int i = 0; i < len; ++i)
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put_pixel(rand() % 16 ? 0 : 0xffffffff);
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}
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void pattern_greys(uint len, uint t) {
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int max = 100; // let's not draw too much current!
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t %= max;
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for (int i = 0; i < len; ++i) {
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put_pixel(t * 0x10101);
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if (++t >= max) t = 0;
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}
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}
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void pattern_solid(uint len, uint t) {
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t = 1;
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for (int i = 0; i < len; ++i) {
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put_pixel(t * 0x10101);
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}
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}
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int level = 8;
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void pattern_fade(uint len, uint t) {
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uint shift = 4;
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uint max = 16; // let's not draw too much current!
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max <<= shift;
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uint slow_t = t / 32;
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slow_t = level;
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slow_t %= max;
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static int error;
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slow_t += error;
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error = slow_t & ((1u << shift) - 1);
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slow_t >>= shift;
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slow_t *= 0x010101;
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for (int i = 0; i < len; ++i) {
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put_pixel(slow_t);
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}
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}
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typedef void (*pattern)(uint len, uint t);
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const struct {
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pattern pat;
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const char *name;
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} pattern_table[] = {
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{pattern_snakes, "Snakes!"},
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{pattern_random, "Random data"},
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{pattern_sparkle, "Sparkles"},
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{pattern_greys, "Greys"},
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// {pattern_solid, "Solid!"},
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// {pattern_fade, "Fade"},
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};
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#define VALUE_PLANE_COUNT (8 + FRAC_BITS)
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// we store value (8 bits + fractional bits of a single color (R/G/B/W) value) for multiple
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// strings, in bit planes. bit plane N has the Nth bit of each string.
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typedef struct {
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// stored MSB first
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uint32_t planes[VALUE_PLANE_COUNT];
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} value_bits_t;
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// Add FRAC_BITS planes of e to s and store in d
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void add_error(value_bits_t *d, const value_bits_t *s, const value_bits_t *e) {
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uint32_t carry_plane = 0;
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// add the FRAC_BITS low planes
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for (int p = VALUE_PLANE_COUNT - 1; p >= 8; p--) {
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uint32_t e_plane = e->planes[p];
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uint32_t s_plane = s->planes[p];
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d->planes[p] = (e_plane ^ s_plane) ^ carry_plane;
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carry_plane = (e_plane & s_plane) | (carry_plane & (s_plane ^ e_plane));
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}
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// then just ripple carry through the non fractional bits
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for (int p = 7; p >= 0; p--) {
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uint32_t s_plane = s->planes[p];
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d->planes[p] = s_plane ^ carry_plane;
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carry_plane &= s_plane;
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}
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}
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typedef struct {
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uint8_t *data;
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uint data_len;
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uint frac_brightness; // 256 = *1.0;
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} string_t;
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// takes 8 bit color values, multiply by brightness and store in bit planes
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void transform_strings(string_t **strings, uint num_strings, value_bits_t *values, uint value_length,
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uint frac_brightness) {
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for (uint v = 0; v < value_length; v++) {
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memset(&values[v], 0, sizeof(values[v]));
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for (int i = 0; i < num_strings; i++) {
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if (v < strings[i]->data_len) {
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// todo clamp?
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uint32_t value = (strings[i]->data[v] * strings[i]->frac_brightness) >> 8u;
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value = (value * frac_brightness) >> 8u;
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for (int j = 0; j < VALUE_PLANE_COUNT && value; j++, value >>= 1u) {
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if (value & 1u) values[v].planes[VALUE_PLANE_COUNT - 1 - j] |= 1u << i;
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}
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}
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}
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}
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}
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void dither_values(const value_bits_t *colors, value_bits_t *state, const value_bits_t *old_state, uint value_length) {
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for (uint i = 0; i < value_length; i++) {
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add_error(state + i, colors + i, old_state + i);
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}
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}
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#define MAX_LENGTH 100
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// requested colors * 4 to allow for WRGB
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static value_bits_t colors[MAX_LENGTH * 4];
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// double buffer the state of the string, since we update next version in parallel with DMAing out old version
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static value_bits_t states[2][MAX_LENGTH * 4];
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// example - string 0 is RGB only
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static uint8_t string0_data[MAX_LENGTH * 3];
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// example - string 1 is WRGB
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static uint8_t string1_data[MAX_LENGTH * 4];
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string_t string0 = {
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.data = string0_data,
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.data_len = sizeof(string0_data),
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.frac_brightness = 0x40,
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};
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string_t string1 = {
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.data = string1_data,
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.data_len = sizeof(string1_data),
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.frac_brightness = 0x100,
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};
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string_t *strings[] = {
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&string0,
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&string1,
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};
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// bit plane content dma channel
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#define DMA_CHANNEL 0
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// chain channel for configuring main dma channel to output from disjoint 8 word fragments of memory
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#define DMA_CB_CHANNEL 1
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#define DMA_CHANNEL_MASK (1u << DMA_CHANNEL)
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#define DMA_CB_CHANNEL_MASK (1u << DMA_CB_CHANNEL)
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#define DMA_CHANNELS_MASK (DMA_CHANNEL_MASK | DMA_CB_CHANNEL_MASK)
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// start of each value fragment (+1 for NULL terminator)
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static uintptr_t fragment_start[MAX_LENGTH * 4 + 1];
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// posted when it is safe to output a new set of values
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static struct semaphore reset_delay_complete_sem;
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// alarm handle for handling delay
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alarm_id_t reset_delay_alarm_id;
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int64_t reset_delay_complete(alarm_id_t id, void *user_data) {
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reset_delay_alarm_id = 0;
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sem_release(&reset_delay_complete_sem);
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// no repeat
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return 0;
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}
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void __isr dma_complete_handler() {
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if (dma_hw->ints0 & DMA_CHANNEL_MASK) {
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// clear IRQ
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dma_hw->ints0 = DMA_CHANNEL_MASK;
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// when the dma is complete we start the reset delay timer
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if (reset_delay_alarm_id) cancel_alarm(reset_delay_alarm_id);
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reset_delay_alarm_id = add_alarm_in_us(400, reset_delay_complete, NULL, true);
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}
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}
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void dma_init(PIO pio, uint sm) {
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dma_claim_mask(DMA_CHANNELS_MASK);
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// main DMA channel outputs 8 word fragments, and then chains back to the chain channel
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dma_channel_config channel_config = dma_channel_get_default_config(DMA_CHANNEL);
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channel_config_set_dreq(&channel_config, pio_get_dreq(pio, sm, true));
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channel_config_set_chain_to(&channel_config, DMA_CB_CHANNEL);
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channel_config_set_irq_quiet(&channel_config, true);
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dma_channel_configure(DMA_CHANNEL,
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&channel_config,
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&pio->txf[sm],
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NULL, // set by chain
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8, // 8 words for 8 bit planes
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false);
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// chain channel sends single word pointer to start of fragment each time
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dma_channel_config chain_config = dma_channel_get_default_config(DMA_CB_CHANNEL);
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dma_channel_configure(DMA_CB_CHANNEL,
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&chain_config,
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&dma_channel_hw_addr(
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DMA_CHANNEL)->al3_read_addr_trig, // ch DMA config (target "ring" buffer size 4) - this is (read_addr trigger)
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NULL, // set later
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1,
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false);
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irq_set_exclusive_handler(DMA_IRQ_0, dma_complete_handler);
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dma_channel_set_irq0_enabled(DMA_CHANNEL, true);
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irq_set_enabled(DMA_IRQ_0, true);
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}
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void output_strings_dma(value_bits_t *bits, uint value_length) {
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for (uint i = 0; i < value_length; i++) {
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fragment_start[i] = (uintptr_t) bits[i].planes; // MSB first
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}
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fragment_start[value_length] = 0;
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dma_channel_hw_addr(DMA_CB_CHANNEL)->al3_read_addr_trig = (uintptr_t) fragment_start;
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}
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int main() {
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//set_sys_clock_48();
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stdio_init_all();
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puts("WS2812 parallel");
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// todo get free sm
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PIO pio = pio0;
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int sm = 0;
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uint offset = pio_add_program(pio, &ws2812_parallel_program);
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ws2812_parallel_program_init(pio, sm, offset, PIN_TX, count_of(strings), 800000);
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sem_init(&reset_delay_complete_sem, 1, 1); // initially posted so we don't block first time
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dma_init(pio, sm);
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int t = 0;
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while (1) {
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int pat = rand() % count_of(pattern_table);
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int dir = (rand() >> 30) & 1 ? 1 : -1;
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if (rand() & 1) dir = 0;
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puts(pattern_table[pat].name);
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puts(dir == 1 ? "(forward)" : dir ? "(backward)" : "(still)");
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int brightness = 0;
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uint current = 0;
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for (int i = 0; i < 1000; ++i) {
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int n = 64;
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current_string_out = string0.data;
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current_string_4color = false;
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pattern_table[pat].pat(n, t);
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current_string_out = string1.data;
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current_string_4color = true;
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pattern_table[pat].pat(n, t);
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transform_strings(strings, count_of(strings), colors, n * 4, brightness);
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dither_values(colors, states[current], states[current ^ 1], n * 4);
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sem_acquire_blocking(&reset_delay_complete_sem);
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output_strings_dma(states[current], n * 4);
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current ^= 1;
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t += dir;
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brightness++;
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if (brightness == (0x20 << FRAC_BITS)) brightness = 0;
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}
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memset(&states, 0, sizeof(states)); // clear out errors
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}
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}
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