From 5bb9ccbdc58f2fad08692d4060a8c2b4bd41e834 Mon Sep 17 00:00:00 2001
From: Adolfo Reyna <adolforeyna@Adolfos-MacBook-Air.local>
Date: Tue, 18 Nov 2025 13:10:54 -0500
Subject: [PATCH] adding oled support

---
 CMakeLists.txt |   8 ++--
 hello_usb.cpp  | 113 +++++++++++++++++++++++++++++++++++++++++++++++++
 pico-ssd1306   |   1 +
 3 files changed, 119 insertions(+), 3 deletions(-)
 create mode 100644 hello_usb.cpp
 create mode 160000 pico-ssd1306

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 704a560..19ced5a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -36,12 +36,14 @@ pico_sdk_init()
 # Add executable. Default name is the project name, version 0.1
 
 if (TARGET tinyusb_device)
-    add_executable(hello_usb
-            hello_usb.c
+        add_executable(hello_usb
+            hello_usb.cpp
             )
 
+    add_subdirectory(pico-ssd1306)
+
     # pull in common dependencies
-    target_link_libraries(hello_usb pico_stdlib)
+    target_link_libraries(hello_usb pico_stdlib pico_ssd1306 hardware_i2c)
 
     # enable usb output, disable uart output
     pico_enable_stdio_usb(hello_usb 1)
diff --git a/hello_usb.cpp b/hello_usb.cpp
new file mode 100644
index 0000000..9aa44c6
--- /dev/null
+++ b/hello_usb.cpp
@@ -0,0 +1,113 @@
+/*
+ * Simple USB Serial Echo Program with Timeout, Reconnect, and Backspace Logic.
+ * Converted to C++ so the project can use the `pico-ssd1306` C++ library.
+ */
+
+#include "pico/stdlib.h"
+#include "pico/time.h" // Needed for time_us_64()
+#include <stdio.h>
+#include <ctype.h>
+
+#include "hardware/i2c.h"
+#include "hardware/gpio.h"
+#include "pico-ssd1306/ssd1306.h"
+
+using namespace pico_ssd1306;
+
+// Define the maximum size for the input string buffer
+#define MAX_INPUT_LEN 64
+// Define the timeout period: 5 seconds in microseconds
+#define TIMEOUT_US 5000000
+// ASCII code for Backspace (often sent as 0x08)
+#define ASCII_BACKSPACE 8
+
+// Helper function to handle the echoing and resetting of the buffer
+void echo_and_reset(char* buffer, int* index_ptr) {
+    if (*index_ptr > 0) {
+        buffer[*index_ptr] = '\0';
+        printf("\nEchoed (ALL CAPS): ");
+        for (int i = 0; buffer[i] != '\0'; i++) {
+            printf("%c", toupper(buffer[i]));
+        }
+        printf("\n");
+    }
+    *index_ptr = 0;
+    printf("> ");
+}
+
+void wait_for_usb_connection() {
+    printf("Waiting for USB host to connect...\n");
+    while (!stdio_usb_connected()) {
+        sleep_ms(100);
+    }
+    printf("\nConnection Established! Starting Echo Session...\n");
+}
+
+void run_echo_session() {
+    char input_buffer[MAX_INPUT_LEN];
+    int buffer_index = 0;
+    uint64_t last_char_time = time_us_64();
+
+    printf("--- Pico USB String Echo Program Started ---\n");
+    printf("Type a sentence (up to %d chars). It will echo on Enter/Timeout.\n", MAX_INPUT_LEN - 2);
+    printf("--------------------------------------------\n");
+    printf("> ");
+
+    while (stdio_usb_connected()) {
+        int c = getchar_timeout_us(0);
+        if (c != PICO_ERROR_TIMEOUT) {
+            last_char_time = time_us_64();
+            char input_char = (char)c;
+            if (input_char == ASCII_BACKSPACE || input_char == 127) {
+                if (buffer_index > 0) {
+                    buffer_index--;
+                    printf("\b \b");
+                }
+            } else if (input_char == '\r' || input_char == '\n') {
+                echo_and_reset(input_buffer, &buffer_index);
+            } else if (buffer_index < (MAX_INPUT_LEN - 1) && isprint(input_char)) {
+                printf("%c", input_char);
+                input_buffer[buffer_index] = input_char;
+                buffer_index++;
+            }
+        }
+
+        if (buffer_index > 0 && (time_us_64() - last_char_time) > TIMEOUT_US) {
+            printf("\n--- Timeout Reached (5.0s silence) ---\n");
+            echo_and_reset(input_buffer, &buffer_index);
+            last_char_time = time_us_64();
+        }
+
+        sleep_us(100);
+    }
+
+    printf("\nHost disconnected. Ending Echo Session.\n");
+}
+
+int main() {
+    stdio_init_all();
+
+    // Initialize I2C for the SSD1306 display (common pins: SDA=GPIO4, SCL=GPIO5)
+    i2c_init(i2c0, 400 * 1000);
+    gpio_set_function(4, GPIO_FUNC_I2C);
+    gpio_set_function(5, GPIO_FUNC_I2C);
+    gpio_pull_up(4);
+    gpio_pull_up(5);
+
+    // Create display object (address 0x3C is common). Adjust size/address if needed.
+    SSD1306 display(i2c0, 0x3C, Size::W128xH64);
+    display.clear();
+    display.sendBuffer();
+    for (int y = 0; y < 64; y++){
+        display.setPixel(64, y);
+    }
+    display.sendBuffer(); //Send buffer to device and show on screen
+
+
+    while (true) {
+        wait_for_usb_connection();
+        run_echo_session();
+    }
+
+    return 0;
+}
diff --git a/pico-ssd1306 b/pico-ssd1306
new file mode 160000
index 0000000..2cec467
--- /dev/null
+++ b/pico-ssd1306
@@ -0,0 +1 @@
+Subproject commit 2cec467a06bb8cd89363e12091bfd2318f7feab6