main.cpp

#include <string.h>
#include <stdlib.h>

#include "lwip/apps/httpd.h"
#include "pico/stdlib.h"
#include "pico/cyw43_arch.h"
#include "pico/multicore.h"
#include "hardware/dma.h"

#include "lwipopts.h"
#include "cgi.h"

#include "shift_register.pio.h"

// Properties of the physical device
#define DISPLAY_LINES (7)
#define DISPLAY_LEDS_PER_LINE (95)
#define WORDS_PER_PHY_LINE ((DISPLAY_LEDS_PER_LINE+31)/32)

// Pins
#define DISPLAY_DATA_PIN (14)
#define DISPLAY_CLOCK_PIN (15)
const uint LINE_PINS[DISPLAY_LINES] = {5, 6, 7, 9, 10, 11, 12};

// Clock speed of display data/clock pin
#define PIO_SERIAL_CLKDIV (125.f / 2.f)

// Render buffer properties
#define CHARACTER_WIDTH (5+1)
#define MAX_NUM_CHARACTERS (200)
#define WORDS_PER_DRAW_LINE (((MAX_NUM_CHARACTERS*CHARACTER_WIDTH)+31)/32)

auto_init_mutex(physical_page_buffer_mutex);


// last frame idx made by frame generator stored here
volatile static char last_valid_buffer = 0;

// in use buffer: which buffer are we currently drawing
volatile static char in_use_buffer = 1;

// font 5x7
static const uint8_t FONT_DATA[] = {
    0x00, 0x00, 0x00, 0x00, 0x00,
    0x3E, 0x5B, 0x4F, 0x5B, 0x3E,
    0x3E, 0x6B, 0x4F, 0x6B, 0x3E,
    0x1C, 0x3E, 0x7C, 0x3E, 0x1C,
    0x18, 0x3C, 0x7E, 0x3C, 0x18,
    0x1C, 0x57, 0x7D, 0x57, 0x1C,
    0x1C, 0x5E, 0x7F, 0x5E, 0x1C,
    0x00, 0x18, 0x3C, 0x18, 0x00,
    0xFF, 0xE7, 0xC3, 0xE7, 0xFF,
    0x00, 0x18, 0x24, 0x18, 0x00,
    0xFF, 0xE7, 0xDB, 0xE7, 0xFF,
    0x30, 0x48, 0x3A, 0x06, 0x0E,
    0x26, 0x29, 0x79, 0x29, 0x26,
    0x40, 0x7F, 0x05, 0x05, 0x07,
    0x40, 0x7F, 0x05, 0x25, 0x3F,
    0x5A, 0x3C, 0xE7, 0x3C, 0x5A,
    0x7F, 0x3E, 0x1C, 0x1C, 0x08,
    0x08, 0x1C, 0x1C, 0x3E, 0x7F,
    0x14, 0x22, 0x7F, 0x22, 0x14,
    0x5F, 0x5F, 0x00, 0x5F, 0x5F,
    0x06, 0x09, 0x7F, 0x01, 0x7F,
    0x00, 0x66, 0x89, 0x95, 0x6A,
    0x60, 0x60, 0x60, 0x60, 0x60,
    0x94, 0xA2, 0xFF, 0xA2, 0x94,
    0x08, 0x04, 0x7E, 0x04, 0x08,
    0x10, 0x20, 0x7E, 0x20, 0x10,
    0x08, 0x08, 0x2A, 0x1C, 0x08,
    0x08, 0x1C, 0x2A, 0x08, 0x08,
    0x1E, 0x10, 0x10, 0x10, 0x10,
    0x0C, 0x1E, 0x0C, 0x1E, 0x0C,
    0x30, 0x38, 0x3E, 0x38, 0x30,
    0x06, 0x0E, 0x3E, 0x0E, 0x06,
    0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x5F, 0x00, 0x00,
    0x00, 0x07, 0x00, 0x07, 0x00,
    0x14, 0x7F, 0x14, 0x7F, 0x14,
    0x24, 0x2A, 0x7F, 0x2A, 0x12,
    0x23, 0x13, 0x08, 0x64, 0x62,
    0x36, 0x49, 0x56, 0x20, 0x50,
    0x00, 0x08, 0x07, 0x03, 0x00,
    0x00, 0x1C, 0x22, 0x41, 0x00,
    0x00, 0x41, 0x22, 0x1C, 0x00,
    0x2A, 0x1C, 0x7F, 0x1C, 0x2A,
    0x08, 0x08, 0x3E, 0x08, 0x08,
    0x00, 0x80, 0x70, 0x30, 0x00,
    0x08, 0x08, 0x08, 0x08, 0x08,
    0x00, 0x00, 0x60, 0x60, 0x00,
    0x20, 0x10, 0x08, 0x04, 0x02,
    0x3E, 0x51, 0x49, 0x45, 0x3E,
    0x00, 0x42, 0x7F, 0x40, 0x00,
    0x72, 0x49, 0x49, 0x49, 0x46,
    0x21, 0x41, 0x49, 0x4D, 0x33,
    0x18, 0x14, 0x12, 0x7F, 0x10,
    0x27, 0x45, 0x45, 0x45, 0x39,
    0x3C, 0x4A, 0x49, 0x49, 0x31,
    0x41, 0x21, 0x11, 0x09, 0x07,
    0x36, 0x49, 0x49, 0x49, 0x36,
    0x46, 0x49, 0x49, 0x29, 0x1E,
    0x00, 0x00, 0x14, 0x00, 0x00,
    0x00, 0x40, 0x34, 0x00, 0x00,
    0x00, 0x08, 0x14, 0x22, 0x41,
    0x14, 0x14, 0x14, 0x14, 0x14,
    0x00, 0x41, 0x22, 0x14, 0x08,
    0x02, 0x01, 0x59, 0x09, 0x06,
    0x3E, 0x41, 0x5D, 0x59, 0x4E,
    0x7C, 0x12, 0x11, 0x12, 0x7C,
    0x7F, 0x49, 0x49, 0x49, 0x36,
    0x3E, 0x41, 0x41, 0x41, 0x22,
    0x7F, 0x41, 0x41, 0x41, 0x3E,
    0x7F, 0x49, 0x49, 0x49, 0x41,
    0x7F, 0x09, 0x09, 0x09, 0x01,
    0x3E, 0x41, 0x41, 0x51, 0x73,
    0x7F, 0x08, 0x08, 0x08, 0x7F,
    0x00, 0x41, 0x7F, 0x41, 0x00,
    0x20, 0x40, 0x41, 0x3F, 0x01,
    0x7F, 0x08, 0x14, 0x22, 0x41,
    0x7F, 0x40, 0x40, 0x40, 0x40,
    0x7F, 0x02, 0x1C, 0x02, 0x7F,
    0x7F, 0x04, 0x08, 0x10, 0x7F,
    0x3E, 0x41, 0x41, 0x41, 0x3E,
    0x7F, 0x09, 0x09, 0x09, 0x06,
    0x3E, 0x41, 0x51, 0x21, 0x5E,
    0x7F, 0x09, 0x19, 0x29, 0x46,
    0x26, 0x49, 0x49, 0x49, 0x32,
    0x03, 0x01, 0x7F, 0x01, 0x03,
    0x3F, 0x40, 0x40, 0x40, 0x3F,
    0x1F, 0x20, 0x40, 0x20, 0x1F,
    0x3F, 0x40, 0x38, 0x40, 0x3F,
    0x63, 0x14, 0x08, 0x14, 0x63,
    0x03, 0x04, 0x78, 0x04, 0x03,
    0x61, 0x59, 0x49, 0x4D, 0x43,
    0x00, 0x7F, 0x41, 0x41, 0x41,
    0x02, 0x04, 0x08, 0x10, 0x20,
    0x00, 0x41, 0x41, 0x41, 0x7F,
    0x04, 0x02, 0x01, 0x02, 0x04,
    0x40, 0x40, 0x40, 0x40, 0x40,
    0x00, 0x03, 0x07, 0x08, 0x00,
    0x20, 0x54, 0x54, 0x78, 0x40,
    0x7F, 0x28, 0x44, 0x44, 0x38,
    0x38, 0x44, 0x44, 0x44, 0x28,
    0x38, 0x44, 0x44, 0x28, 0x7F,
    0x38, 0x54, 0x54, 0x54, 0x18,
    0x00, 0x08, 0x7E, 0x09, 0x02,
    0x18, 0xA4, 0xA4, 0x9C, 0x78,
    0x7F, 0x08, 0x04, 0x04, 0x78,
    0x00, 0x44, 0x7D, 0x40, 0x00,
    0x20, 0x40, 0x40, 0x3D, 0x00,
    0x7F, 0x10, 0x28, 0x44, 0x00,
    0x00, 0x41, 0x7F, 0x40, 0x00,
    0x7C, 0x04, 0x78, 0x04, 0x78,
    0x7C, 0x08, 0x04, 0x04, 0x78,
    0x38, 0x44, 0x44, 0x44, 0x38,
    0xFC, 0x18, 0x24, 0x24, 0x18,
    0x18, 0x24, 0x24, 0x18, 0xFC,
    0x7C, 0x08, 0x04, 0x04, 0x08,
    0x48, 0x54, 0x54, 0x54, 0x24,
    0x04, 0x04, 0x3F, 0x44, 0x24,
    0x3C, 0x40, 0x40, 0x20, 0x7C,
    0x1C, 0x20, 0x40, 0x20, 0x1C,
    0x3C, 0x40, 0x30, 0x40, 0x3C,
    0x44, 0x28, 0x10, 0x28, 0x44,
    0x4C, 0x90, 0x90, 0x90, 0x7C,
    0x44, 0x64, 0x54, 0x4C, 0x44,
    0x00, 0x08, 0x36, 0x41, 0x00,
    0x00, 0x00, 0x77, 0x00, 0x00,
    0x00, 0x41, 0x36, 0x08, 0x00,
    0x02, 0x01, 0x02, 0x04, 0x02,
    0x3C, 0x26, 0x23, 0x26, 0x3C,
    0x1E, 0xA1, 0xA1, 0x61, 0x12,
    0x3A, 0x40, 0x40, 0x20, 0x7A,
    0x38, 0x54, 0x54, 0x55, 0x59,
    0x21, 0x55, 0x55, 0x79, 0x41,
    0x21, 0x54, 0x54, 0x78, 0x41,
    0x21, 0x55, 0x54, 0x78, 0x40,
    0x20, 0x54, 0x55, 0x79, 0x40,
    0x0C, 0x1E, 0x52, 0x72, 0x12,
    0x39, 0x55, 0x55, 0x55, 0x59,
    0x39, 0x54, 0x54, 0x54, 0x59,
    0x39, 0x55, 0x54, 0x54, 0x58,
    0x00, 0x00, 0x45, 0x7C, 0x41,
    0x00, 0x02, 0x45, 0x7D, 0x42,
    0x00, 0x01, 0x45, 0x7C, 0x40,
    0xF0, 0x29, 0x24, 0x29, 0xF0,
    0xF0, 0x28, 0x25, 0x28, 0xF0,
    0x7C, 0x54, 0x55, 0x45, 0x00,
    0x20, 0x54, 0x54, 0x7C, 0x54,
    0x7C, 0x0A, 0x09, 0x7F, 0x49,
    0x32, 0x49, 0x49, 0x49, 0x32,
    0x32, 0x48, 0x48, 0x48, 0x32,
    0x32, 0x4A, 0x48, 0x48, 0x30,
    0x3A, 0x41, 0x41, 0x21, 0x7A,
    0x3A, 0x42, 0x40, 0x20, 0x78,
    0x00, 0x9D, 0xA0, 0xA0, 0x7D,
    0x39, 0x44, 0x44, 0x44, 0x39,
    0x3D, 0x40, 0x40, 0x40, 0x3D,
    0x3C, 0x24, 0xFF, 0x24, 0x24,
    0x48, 0x7E, 0x49, 0x43, 0x66,
    0x2B, 0x2F, 0xFC, 0x2F, 0x2B,
    0xFF, 0x09, 0x29, 0xF6, 0x20,
    0xC0, 0x88, 0x7E, 0x09, 0x03,
    0x20, 0x54, 0x54, 0x79, 0x41,
    0x00, 0x00, 0x44, 0x7D, 0x41,
    0x30, 0x48, 0x48, 0x4A, 0x32,
    0x38, 0x40, 0x40, 0x22, 0x7A,
    0x00, 0x7A, 0x0A, 0x0A, 0x72,
    0x7D, 0x0D, 0x19, 0x31, 0x7D,
    0x26, 0x29, 0x29, 0x2F, 0x28,
    0x26, 0x29, 0x29, 0x29, 0x26,
    0x30, 0x48, 0x4D, 0x40, 0x20,
    0x38, 0x08, 0x08, 0x08, 0x08,
    0x08, 0x08, 0x08, 0x08, 0x38,
    0x2F, 0x10, 0xC8, 0xAC, 0xBA,
    0x2F, 0x10, 0x28, 0x34, 0xFA,
    0x00, 0x00, 0x7B, 0x00, 0x00,
    0x08, 0x14, 0x2A, 0x14, 0x22,
    0x22, 0x14, 0x2A, 0x14, 0x08,
    0xAA, 0x00, 0x55, 0x00, 0xAA,
    0xAA, 0x55, 0xAA, 0x55, 0xAA,
    0x00, 0x00, 0x00, 0xFF, 0x00,
    0x10, 0x10, 0x10, 0xFF, 0x00,
    0x14, 0x14, 0x14, 0xFF, 0x00,
    0x10, 0x10, 0xFF, 0x00, 0xFF,
    0x10, 0x10, 0xF0, 0x10, 0xF0,
    0x14, 0x14, 0x14, 0xFC, 0x00,
    0x14, 0x14, 0xF7, 0x00, 0xFF,
    0x00, 0x00, 0xFF, 0x00, 0xFF,
    0x14, 0x14, 0xF4, 0x04, 0xFC,
    0x14, 0x14, 0x17, 0x10, 0x1F,
    0x10, 0x10, 0x1F, 0x10, 0x1F,
    0x14, 0x14, 0x14, 0x1F, 0x00,
    0x10, 0x10, 0x10, 0xF0, 0x00,
    0x00, 0x00, 0x00, 0x1F, 0x10,
    0x10, 0x10, 0x10, 0x1F, 0x10,
    0x10, 0x10, 0x10, 0xF0, 0x10,
    0x00, 0x00, 0x00, 0xFF, 0x10,
    0x10, 0x10, 0x10, 0x10, 0x10,
    0x10, 0x10, 0x10, 0xFF, 0x10,
    0x00, 0x00, 0x00, 0xFF, 0x14,
    0x00, 0x00, 0xFF, 0x00, 0xFF,
    0x00, 0x00, 0x1F, 0x10, 0x17,
    0x00, 0x00, 0xFC, 0x04, 0xF4,
    0x14, 0x14, 0x17, 0x10, 0x17,
    0x14, 0x14, 0xF4, 0x04, 0xF4,
    0x00, 0x00, 0xFF, 0x00, 0xF7,
    0x14, 0x14, 0x14, 0x14, 0x14,
    0x14, 0x14, 0xF7, 0x00, 0xF7,
    0x14, 0x14, 0x14, 0x17, 0x14,
    0x10, 0x10, 0x1F, 0x10, 0x1F,
    0x14, 0x14, 0x14, 0xF4, 0x14,
    0x10, 0x10, 0xF0, 0x10, 0xF0,
    0x00, 0x00, 0x1F, 0x10, 0x1F,
    0x00, 0x00, 0x00, 0x1F, 0x14,
    0x00, 0x00, 0x00, 0xFC, 0x14,
    0x00, 0x00, 0xF0, 0x10, 0xF0,
    0x10, 0x10, 0xFF, 0x10, 0xFF,
    0x14, 0x14, 0x14, 0xFF, 0x14,
    0x10, 0x10, 0x10, 0x1F, 0x00,
    0x00, 0x00, 0x00, 0xF0, 0x10,
    0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
    0xF0, 0xF0, 0xF0, 0xF0, 0xF0,
    0xFF, 0xFF, 0xFF, 0x00, 0x00,
    0x00, 0x00, 0x00, 0xFF, 0xFF,
    0x0F, 0x0F, 0x0F, 0x0F, 0x0F,
    0x38, 0x44, 0x44, 0x38, 0x44,
    0x7C, 0x2A, 0x2A, 0x3E, 0x14,
    0x7E, 0x02, 0x02, 0x06, 0x06,
    0x02, 0x7E, 0x02, 0x7E, 0x02,
    0x63, 0x55, 0x49, 0x41, 0x63,
    0x38, 0x44, 0x44, 0x3C, 0x04,
    0x40, 0x7E, 0x20, 0x1E, 0x20,
    0x06, 0x02, 0x7E, 0x02, 0x02,
    0x99, 0xA5, 0xE7, 0xA5, 0x99,
    0x1C, 0x2A, 0x49, 0x2A, 0x1C,
    0x4C, 0x72, 0x01, 0x72, 0x4C,
    0x30, 0x4A, 0x4D, 0x4D, 0x30,
    0x30, 0x48, 0x78, 0x48, 0x30,
    0xBC, 0x62, 0x5A, 0x46, 0x3D,
    0x3E, 0x49, 0x49, 0x49, 0x00,
    0x7E, 0x01, 0x01, 0x01, 0x7E,
    0x2A, 0x2A, 0x2A, 0x2A, 0x2A,
    0x44, 0x44, 0x5F, 0x44, 0x44,
    0x40, 0x51, 0x4A, 0x44, 0x40,
    0x40, 0x44, 0x4A, 0x51, 0x40,
    0x00, 0x00, 0xFF, 0x01, 0x03,
    0xE0, 0x80, 0xFF, 0x00, 0x00,
    0x08, 0x08, 0x6B, 0x6B, 0x08,
    0x36, 0x12, 0x36, 0x24, 0x36,
    0x06, 0x0F, 0x09, 0x0F, 0x06,
    0x00, 0x00, 0x18, 0x18, 0x00,
    0x00, 0x00, 0x10, 0x10, 0x00,
    0x30, 0x40, 0xFF, 0x01, 0x01,
    0x00, 0x1F, 0x01, 0x01, 0x1E,
    0x00, 0x19, 0x1D, 0x17, 0x12,
    0x00, 0x3C, 0x3C, 0x3C, 0x3C,
    0x00, 0x00, 0x00, 0x00, 0x00,
    0xFF, 0xFF, 0xFF, 0xFF, 0xFF
};

// We eventually arrived at 3 drawing buffers:
// 1 would not be enough, since then you draw and read from the same buffer, so you might have tearing
// 2 would not be enough, since then the same buffer would get drawn over and over
// 3 is enough
volatile static uint32_t physical_page_buffer[3][DISPLAY_LINES][WORDS_PER_PHY_LINE] = {0};

// Render buffer related variables
// These are not behind a mutex, since there is only one thread accessing these (and we made LWIP polling)
uint32_t render_buffer[DISPLAY_LINES][WORDS_PER_DRAW_LINE] = {0};
uint32_t ms_per_scroll_tick = 1000;
uint32_t render_buffer_size = 1;
absolute_time_t animation_begin_time = 0;

void render_text(const char* text, uint32_t _ms_per_scroll_tick) {
    printf("Rendering `%s` at %ld ms interval\n", text, _ms_per_scroll_tick);
    if (_ms_per_scroll_tick == 0) {
        // basically no movement
        ms_per_scroll_tick = UINT32_MAX;
    } else {
        ms_per_scroll_tick = _ms_per_scroll_tick;
    }

    animation_begin_time = get_absolute_time();
    const size_t text_len = strlen(text);
    size_t current_text_pos = 0;
    memset(render_buffer, 0, DISPLAY_LINES*WORDS_PER_DRAW_LINE*sizeof(uint32_t));

    size_t pixel_offset = 0;
    while (true) {
        if (current_text_pos >= text_len) break;
        if (current_text_pos >= MAX_NUM_CHARACTERS) break;
        // 5 = bytes per character in the font array
        const uint8_t* c = FONT_DATA + text[current_text_pos]*5;
        for (int i = 0; i < CHARACTER_WIDTH - 1; i++) {
            if (c[i] == 0) {
                continue;
            }
            for (int line = 0; line < DISPLAY_LINES; line++) {
                render_buffer[line][pixel_offset/32] |= ((c[i] >> line) & 0b1) << (pixel_offset % 32);
            }
            pixel_offset++;
        }
        if (text[current_text_pos] == ' ') {
            // Space, add some extra space because otherwise, there is none
            pixel_offset += 2;
        }

        pixel_offset += 1;
        current_text_pos += 1;
        render_buffer_size = pixel_offset;
    }
    if (_ms_per_scroll_tick == 0) {
        render_buffer_size = DISPLAY_LEDS_PER_LINE;
    }
}


void core1_entry() {
    uint offset = pio_add_program(pio0, &pio_shiftregister_program);
    pio_shiftregister_program_init(pio0, 0, offset, DISPLAY_CLOCK_PIN, DISPLAY_DATA_PIN, PIO_SERIAL_CLKDIV);

    int dma_chan = dma_claim_unused_channel(true);
    dma_channel_config c = dma_channel_get_default_config(dma_chan);
    channel_config_set_transfer_data_size(&c, DMA_SIZE_32);
    channel_config_set_read_increment(&c, true);
    channel_config_set_dreq(&c, DREQ_PIO0_TX0);

    dma_channel_configure(
        dma_chan,
        &c,
        &pio0_hw->txf[0], // Write address (only need to set this once)
        NULL,             // Don't provide a read address yet
        WORDS_PER_PHY_LINE,   // Number of transfers
        false             // Don't start yet
    );

    for (int line = 0; line < DISPLAY_LINES; line++) {
        gpio_init(LINE_PINS[line]);
        gpio_set_dir(LINE_PINS[line], GPIO_OUT);
        gpio_put(LINE_PINS[line], 0);
    }

    while (true) {
        uint32_t owner_out = 0;
        // Try to update current buffer idx, if fails, then don't
        if (mutex_try_enter(&physical_page_buffer_mutex, &owner_out)){
            in_use_buffer = last_valid_buffer;
            mutex_exit(&physical_page_buffer_mutex);
        }

        int buffer_idx = in_use_buffer;
        // each line consists of two phases: first, clock in all data; then light up the line for some time
        // we have 413 us for this; if we take longer, too bad, the leds will be dimmer
        for (int line = 0; line < DISPLAY_LINES; line++) {
            absolute_time_t finish = make_timeout_time_us(413);

            dma_channel_set_read_addr(dma_chan, &physical_page_buffer[buffer_idx][line][0], true);
            dma_channel_wait_for_finish_blocking(dma_chan);

            while (get_absolute_time() < finish) {
                tight_loop_contents();
            }

            // light up line; 734 us
            gpio_put(LINE_PINS[line], 1);
            sleep_us(734);
            gpio_put(LINE_PINS[line], 0);
        }
        sleep_us(700);
    }
}

void drawing_function() {
    // find a free buffer
    // first, exclude the buffer that is currently in use
    // then, exclude the buffer that we most recently drawn to (might be the same buffer)
    unsigned char buffer_to_draw_to = 0;
    mutex_enter_blocking(&physical_page_buffer_mutex);
    {
        for (buffer_to_draw_to = 0; buffer_to_draw_to < 3; buffer_to_draw_to++) {
            if (in_use_buffer != buffer_to_draw_to && last_valid_buffer != buffer_to_draw_to)
                break;
        }
    }
    mutex_exit(&physical_page_buffer_mutex);
    // clear old content
    for (int line = 0; line < DISPLAY_LINES; line++) {
        for (int word = 0; word < (WORDS_PER_PHY_LINE); word++) {
            physical_page_buffer[buffer_to_draw_to][line][word] = 0;
        }
    }

    for (int line = 0; line < DISPLAY_LINES; line++) {
        size_t render_base_pos = ((uint32_t)(absolute_time_diff_us(animation_begin_time, get_absolute_time()) / 1000)) / ms_per_scroll_tick;
        for (int i = 0; i < DISPLAY_LEDS_PER_LINE; i++) {
            size_t render_pos = (render_base_pos + i) % render_buffer_size;
            uint32_t phy_pixel = (render_buffer[line][render_pos/32] >> (render_pos%32)) & 1;
            uint32_t phy_pos = WORDS_PER_PHY_LINE*32 - 1 - i;
            physical_page_buffer[buffer_to_draw_to][line][phy_pos/32] |= phy_pixel << (phy_pos % 32);
        }
    }
    // done drawing, mark buffer as most recent
    mutex_enter_blocking(&physical_page_buffer_mutex);
    {
        last_valid_buffer = buffer_to_draw_to;
    }
    mutex_exit(&physical_page_buffer_mutex);
}


int main() {
    stdio_init_all();

    if (cyw43_arch_init()) {
        printf("failed to initialise\n");
        return 1;
    }

    multicore_launch_core1(core1_entry);

    cyw43_arch_enable_sta_mode();
    // this seems to be the best be can do using the predefined `cyw43_pm_value` macro:
    // cyw43_wifi_pm(&cyw43_state, CYW43_PERFORMANCE_PM);
    // however it doesn't use the `CYW43_NO_POWERSAVE_MODE` value, so we do this instead:
    cyw43_wifi_pm(&cyw43_state, cyw43_pm_value(CYW43_NO_POWERSAVE_MODE, 20, 1, 1, 1));
    cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 1);
    render_text("CONNECTING", 0);
    cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 0);
    drawing_function();

    printf("Connecting to WiFi...\n");
    if (cyw43_arch_wifi_connect_timeout_ms(WIFI_SSID, WIFI_PASSWORD, CYW43_AUTH_WPA2_AES_PSK, 30000)) {
        printf("Failed to connect.\n");
        return 1;
    } else {
        printf("Connected.\n");

        extern cyw43_t cyw43_state;
        auto ip_addr = cyw43_state.netif[CYW43_ITF_STA].ip_addr.addr;
        printf("IP Address: %lu.%lu.%lu.%lu\n", ip_addr & 0xFF, (ip_addr >> 8) & 0xFF, (ip_addr >> 16) & 0xFF, ip_addr >> 24);
        char buffer[3*4+3+1] = {0};
        snprintf(buffer, sizeof(buffer), "%lu.%lu.%lu.%lu", ip_addr & 0xFF, (ip_addr >> 8) & 0xFF, (ip_addr >> 16) & 0xFF, ip_addr >> 24);
        render_text(buffer, 0);
    }
    // turn on LED to signal connected
    cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, 1);

    httpd_init();
    cgi_init();

    printf("Http server initialized.\n");

    for (;;) {
        drawing_function();
        cyw43_arch_poll();
    }
}