added code to initialize display and render on screen the adc samples

4 files changed, 306 insertions, 6 deletions

diff --git a/firmware/src/debug.hpp b/firmware/src/debug.hpp
index 856da38..49be259 100644
--- a/firmware/src/debug.hpp
+++ b/firmware/src/debug.hpp
@@ -3,10 +3,18 @@
 namespace debug
 {
 
+static void
+toggle_led() {
+    gpio_xor_mask(1u << PICO_DEFAULT_LED_PIN);
+}
 void
 init()
 {
     stdio_init_all();
+    gpio_init(PICO_DEFAULT_LED_PIN);
+    gpio_set_dir(PICO_DEFAULT_LED_PIN, 1);
+    gpio_put(PICO_DEFAULT_LED_PIN, !PICO_DEFAULT_LED_PIN_INVERTED);
+
 }
 
 }
diff --git a/firmware/src/display.hpp b/firmware/src/display.hpp
index e2dabf2..b7a6cd0 100644
--- a/firmware/src/display.hpp
+++ b/firmware/src/display.hpp
@@ -1,22 +1,256 @@
+#pragma once
+#include "font.hpp"
+
+#include <cstring>
+#include <format>
+#include <string>
+#include <cstdint>
+
 #include "hardware/i2c.h"
 
 namespace display
 {
 
-// I2C0 on GPIO8 (SDA) and GPIO9 (SCL) running at 400KHz
-constexpr auto I2C_PORT = i2c0;
-constexpr unsigned I2C_SDA = 8;
-constexpr unsigned I2C_SCL = 9;
+// I2C1 on GPIO6 (SDA) and GPIO7 (SCL) running at 400KHz
+constexpr auto I2C_PORT = i2c1;
+constexpr unsigned I2C_SDA = 6;
+constexpr unsigned I2C_SCL = 7;
+
+// SSD1036 configuration
+constexpr auto SSD1306_ADDR = 0x3c;
+constexpr auto SSD1036_BYTES_PER_PAGE = 128;
+
+constexpr unsigned DISPLAY_WIDTH = 128;
+constexpr unsigned DISPLAY_HEIGHT = 64;
+
+constexpr unsigned MAX_W = (DISPLAY_WIDTH - 1);
+constexpr unsigned MAX_H = (DISPLAY_HEIGHT - 1);
+
+// FRAME BUFFER
+static uint8_t framebuffer[DISPLAY_HEIGHT * DISPLAY_WIDTH / 8];
+
+typedef enum
+{
+  // Fundamental commands
+  SET_CONTRAST = 0x81,         // Double byte command to select 1 out of
+                               // 256 contrast steps.
+  SET_ENTIRE_DISP_ON = 0xa4,   // Bit0 = 0: Output follows RAM content.
+                               // Bit0 = 1: Output ignores RAM content,
+                               //           all pixels are turned on.
+  SET_NORMAL_INVERTED = 0xa6,  // Bit0 = 0: Normal display.
+                               // Bit0 = 1: Inverted display.
+  SET_DISP_ON_OFF = 0xae,      // Bit0 = 0: Display off, sleep mode.
+                               // Bit0 = 1: Display on, normal mode.
+
+  // Addressing setting Commands
+  SET_ADDRESSING_MODE = 0x20,  // Double byte command to set memory
+                               // addressing mode.
+  SET_COLUMN_ADDRESS = 0x21,   // Tripple byte command to setup column start
+                               // and end address.
+  SET_PAGE_ADDRESS = 0x22,     // Tripple byte command to setup page start and
+                               // end address.
+
+  // Hardware configuration (panel resolution and layout related) commands
+  SET_DISP_START_LINE = 0x40,  // Set display RAM display start line
+                               // register. Valid values are 0 to 63.
+  SET_SEGMENT_REMAP = 0xa0,    // Bit 0 = 0: Map col addr 0 to SEG0.
+                               // Bit 0 = 1: Map col addr 127 to SEG0.
+  SET_MUX_RATIO = 0xa8,        // Double byte command to configure display
+                               // height. Valid height values are 15 to 63.
+  SET_COM_OUTPUT_DIR = 0xc0,   // Bit 3 = 0: Scan from 0 to N-1.
+                               // Bit 3 = 1: Scan from N-1 to 0. (N=height)
+  SET_DISP_OFFSET = 0xd3,      // Double byte command to configure vertical
+                               // display shift. Valid values are 0 to 63.
+  SET_COM_PINS_CONFIG = 0xda,  // Double byte command to set COM pins
+                               // hardware configuration.
+
+  // Timing and driving scheme setting commands
+  SET_DCLK_FOSC = 0xd5,        // Double byte command to set display clock
+                               // divide ratio and oscillator frequency.
+  SET_PRECHARGE_PERIOD = 0xd9, // Double byte command to set pre-charge
+                               // period.
+  SET_VCOM_DESEL_LEVEL = 0xdb, // Double byte command to set VCOMH deselect
+                               // level.
+
+  // Charge pump command
+  SET_CHARGE_PUMP = 0x8d,      // Double byte command to enable/disable
+                               // charge pump.
+                               // Byte2 = 0x10: Disable charge pump.
+                               // Byte2 = 0x14: Enable charge pump.
+} ssd1306_commands;
+
+static bool
+write_commands(uint8_t command)
+{
+    uint8_t data[] = {0x00, command};
+    // send command via I2C
+    auto write_result = i2c_write_blocking(I2C_PORT, SSD1306_ADDR, data, sizeof(data), false);
+    return write_result == sizeof(data);
+}
+
+static bool
+write_framebuffer(const uint8_t *data, size_t length) {
+    // SSD1306 data-control byte followed by pixel data.
+    // Send in chunks to keep the transfer buffer small.
+    uint8_t packet[17];
+    packet[0] = 0x40;
+
+    size_t offset = 0;
+
+    while (offset < length) {
+        size_t chunk = length - offset;
+
+        if (chunk > 16) {
+            chunk = 16;
+        }
+
+        memcpy(&packet[1], &data[offset], chunk);
+
+        int result = i2c_write_blocking(
+            I2C_PORT,
+            SSD1306_ADDR,
+            packet,
+            chunk + 1,
+            false
+        );
+
+        if (result != (int)(chunk + 1)) {
+            return false;
+        }
+
+        offset += chunk;
+    }
+
+    return true;
+}
+
+static bool
+diplay_init()
+{
+    // Initialize the SDD1306 controller
+    const uint8_t commands[] = {
+    SET_DISP_ON_OFF | 0x00,         // Display off.
+    SET_DCLK_FOSC, 0x80,            // Set clock divide ratio and oscillator
+                                    //   frequency.
+    SET_MUX_RATIO, 0x3f,            // Set display height.
+    SET_DISP_OFFSET, 0x00,          // Set vertical display shift to 0.
+    SET_DISP_START_LINE,            // Set display RAM display start line
+                                    //   register to 0.
+    SET_CHARGE_PUMP, 0x14,          // Enable charge pump.
+    SET_SEGMENT_REMAP | 0x01,       // Map col addr 127 to SEG0.
+    SET_COM_OUTPUT_DIR | 0x08,      // Scan from N-1 to 0. (N=height)
+    SET_COM_PINS_CONFIG, 0x12,      // Set COM pins hardware configuration to
+                                    //   0x12.
+    SET_CONTRAST, 0xcf,             // Set contrast to 0xcf
+    SET_PRECHARGE_PERIOD, 0xf1,     // Set pre-charge to 0xf1
+    SET_VCOM_DESEL_LEVEL, 0x40,     // Set VCOMH deselect to 0x40
+    SET_ENTIRE_DISP_ON,             // Output follows RAM content.
+    SET_NORMAL_INVERTED | 0x00,     // Normal display.
+    SET_ADDRESSING_MODE, 0x00,      // Set addressing mode to horizontal mode.
+    SET_COLUMN_ADDRESS, 0x00, 0x7f, // Set column start and end address.
+    SET_PAGE_ADDRESS, 0x00, 0x07,   // Set page start and end address.
+    SET_DISP_ON_OFF | 0x01,         // Display on.
+    };
+
+    for (uint8_t command : commands) {
+        if (!write_commands(command)) {
+            return false;
+        }
+    }
+
+    memset(framebuffer, 0, sizeof(framebuffer));
+
+    return true;
+}
+
+static bool
+display_update()
+{
+    const uint8_t commands[] = {
+        SET_COLUMN_ADDRESS, 0x00, 0x7f, // Column range: 0-127
+        SET_PAGE_ADDRESS, 0x00, 0x07, // Page range: 0-7
+    };
+
+    for (uint8_t command : commands) {
+        if (!write_commands(command)) {
+            return false;
+        }
+    }
+
+    return write_framebuffer(framebuffer, sizeof(framebuffer));
+
+}
 
 void
 init()
 {
+    // Initialize I2C protocol
     i2c_init(I2C_PORT, 400*1000);
     
     gpio_set_function(I2C_SDA, GPIO_FUNC_I2C);
     gpio_set_function(I2C_SCL, GPIO_FUNC_I2C);
     gpio_pull_up(I2C_SDA);
     gpio_pull_up(I2C_SCL);
+
+    // Initialize the display
+    if (!diplay_init()) {
+        while (true) {
+            // Display not responding, stop here.
+            sleep_ms(1000);
+        }
+    }
+
+}
+
+
+
+    static void draw_char(int x, int y, char character, int scale = 1)
+{
+    const Glyph *glyph = find_glyph(character);
+
+    if (glyph == nullptr) {
+        glyph = find_glyph(' ');
+    }
+
+    for (int col = 0; col < 5; ++col) {
+        uint8_t bits = glyph->columns[col];
+
+        for (int row = 0; row < 7; ++row) {
+            if (bits & (1u << row)) {
+                for (int dx = 0; dx < scale; ++dx) {
+                    for (int dy = 0; dy < scale; ++dy) {
+                        int px = x + col * scale + dx;
+                        int py = y + row * scale + dy;
+
+                        if (px < 0 || px >= DISPLAY_WIDTH ||
+                            py < 0 || py >= DISPLAY_HEIGHT) {
+                            continue;
+                            }
+
+                        int index = px + (py / 8) * DISPLAY_WIDTH;
+
+                        framebuffer[index] |=
+                            (uint8_t)(1u << (py % 8));
+                    }
+                }
+            }
+        }
+    }
+}
+static void draw_text(int x, int y, const char *text, int scale = 1)
+{
+    while (*text) {
+        draw_char(x, y, *text++, scale);
+        x += 6 * scale;
+    }
+}
+
+static void
+render_framebuffer(uint8_t pot_a, uint8_t pot_b) {
+    memset(framebuffer, 0, sizeof(framebuffer));
+    draw_text(10, 8, "XIAO RP2040", 2);
+    draw_text(10, 30, std::format("POT A: {}\n", static_cast<std::uint32_t>(pot_a)).c_str(), 1);
+    draw_text(10, 50, std::format("POT C: {}\n", static_cast<std::uint32_t>(pot_b)).c_str(), 1);
 }
 
 }
diff --git a/firmware/src/firmware.cpp b/firmware/src/firmware.cpp
index fc5bdd7..8483ada 100644
--- a/firmware/src/firmware.cpp
+++ b/firmware/src/firmware.cpp
@@ -8,15 +8,21 @@
 void
 update()
 {
-    for (auto const [value, changed] : adc::get_samples())
+    const auto samples = adc::get_samples();
+    for (auto const [value, changed] : samples)
     {
         if (!changed) continue;
 
         midi::send_message();
-        // update framebuffer
+
     }
+    // update framebuffer
+    display::render_framebuffer(samples[0].value, samples[1].value);
 
     // send frame to display
+    display::display_update();
+
+    debug::toggle_led();
 }
 
 [[noreturn]] int
diff --git a/firmware/src/font.hpp b/firmware/src/font.hpp
new file mode 100644
index 0000000..5f4f4bc
--- /dev/null
+++ b/firmware/src/font.hpp
@@ -0,0 +1,52 @@
+// ============================================================
+// Tiny 5x7 font: digits, letters and punctuation
+// ============================================================
+
+struct Glyph {
+    char character;
+    uint8_t columns[5];
+};
+
+static const Glyph font[] = {
+    {' ', {0x00,0x00,0x00,0x00,0x00}},
+    {'.', {0x00,0x60,0x60,0x00,0x00}},
+    {':', {0x00,0x36,0x36,0x00,0x00}},
+    {'-', {0x08,0x08,0x08,0x08,0x08}},
+    {'+', {0x08,0x08,0x3E,0x08,0x08}},
+    {'0', {0x3E,0x51,0x49,0x45,0x3E}},
+    {'1', {0x00,0x42,0x7F,0x40,0x00}},
+    {'2', {0x42,0x61,0x51,0x49,0x46}},
+    {'3', {0x21,0x41,0x45,0x4B,0x31}},
+    {'4', {0x18,0x14,0x12,0x7F,0x10}},
+    {'5', {0x27,0x45,0x45,0x45,0x39}},
+    {'6', {0x3C,0x4A,0x49,0x49,0x30}},
+    {'7', {0x01,0x71,0x09,0x05,0x03}},
+    {'8', {0x36,0x49,0x49,0x49,0x36}},
+    {'9', {0x06,0x49,0x49,0x29,0x1E}},
+    {'A', {0x7E,0x11,0x11,0x11,0x7E}},
+    {'C', {0x3E,0x41,0x41,0x41,0x22}},
+    {'E', {0x7F,0x49,0x49,0x49,0x41}},
+    {'H', {0x7F,0x08,0x08,0x08,0x7F}},
+    {'I', {0x00,0x41,0x7F,0x41,0x00}},
+    {'M', {0x7F,0x02,0x0C,0x02,0x7F}},
+    {'N', {0x7F,0x04,0x08,0x10,0x7F}},
+    {'O', {0x3E,0x41,0x41,0x41,0x3E}},
+    {'P', {0x7F,0x09,0x09,0x09,0x06}},
+    {'R', {0x7F,0x09,0x19,0x29,0x46}},
+    {'S', {0x46,0x49,0x49,0x49,0x31}},
+    {'T', {0x01,0x01,0x7F,0x01,0x01}},
+    {'U', {0x3F,0x40,0x40,0x40,0x3F}},
+    {'X', {0x63,0x14,0x08,0x14,0x63}},
+    {'Y', {0x07,0x08,0x70,0x08,0x07}}
+};
+
+static const Glyph *find_glyph(char character)
+{
+    for (const Glyph &glyph : font) {
+        if (glyph.character == character) {
+            return &glyph;
+        }
+    }
+
+    return nullptr;
+}