122 lines
3.9 KiB
C++
122 lines
3.9 KiB
C++
/*
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* Simple USB Serial Echo Program with Timeout, Reconnect, and Backspace Logic.
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* Converted to C++ so the project can use the `pico-ssd1306` C++ library.
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*/
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#include "pico/stdlib.h"
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#include "pico/time.h" // Needed for time_us_64()
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#include <stdio.h>
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#include <ctype.h>
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#include <cstring>
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#include "display.h"
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// Holds last echoed line for display
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static char g_last_echo[128] = "";
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// Define the maximum size for the input string buffer
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#define MAX_INPUT_LEN 64
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// Define the timeout period: 5 seconds in microseconds
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#define TIMEOUT_US 5000000
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// ASCII code for Backspace (often sent as 0x08)
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#define ASCII_BACKSPACE 8
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// Helper function to handle the echoing and resetting of the buffer
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void echo_and_reset(char* buffer, int* index_ptr, DisplayManager &display) {
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if (*index_ptr > 0) {
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buffer[*index_ptr] = '\0';
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// Print to USB serial (ALL CAPS)
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printf("\nEchoed (ALL CAPS): ");
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for (int i = 0; buffer[i] != '\0'; i++) {
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char ch = toupper(buffer[i]);
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printf("%c", ch);
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}
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printf("\n");
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// Save last echoed (all caps) for display
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size_t i = 0;
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for (; buffer[i] != '\0' && i < sizeof(g_last_echo) - 1; ++i) {
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g_last_echo[i] = (char)toupper(buffer[i]);
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}
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g_last_echo[i] = '\0';
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}
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*index_ptr = 0;
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printf("> ");
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// Update OLED to show cleared input and last echo
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display.set_last_echo(g_last_echo);
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display.refresh("", g_last_echo);
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}
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void wait_for_usb_connection() {
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printf("Waiting for USB host to connect...\n");
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while (!stdio_usb_connected()) {
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sleep_ms(100);
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}
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printf("\nConnection Established! Starting Echo Session...\n");
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}
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void run_echo_session(DisplayManager &display) {
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char input_buffer[MAX_INPUT_LEN];
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int buffer_index = 0;
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uint64_t last_char_time = time_us_64();
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printf("--- Pico USB String Echo Program Started ---\n");
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printf("Type a sentence (up to %d chars). It will echo on Enter/Timeout.\n", MAX_INPUT_LEN - 2);
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printf("--------------------------------------------\n");
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printf("> ");
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while (stdio_usb_connected()) {
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int c = getchar_timeout_us(0);
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if (c != PICO_ERROR_TIMEOUT) {
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last_char_time = time_us_64();
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char input_char = (char)c;
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if (input_char == ASCII_BACKSPACE || input_char == 127) {
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if (buffer_index > 0) {
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buffer_index--;
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printf("\b \b");
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// update display to reflect removed char
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input_buffer[buffer_index] = '\0';
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display.refresh(input_buffer, g_last_echo);
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}
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} else if (input_char == '\r' || input_char == '\n') {
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echo_and_reset(input_buffer, &buffer_index, display);
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// after echo_and_reset the display is refreshed inside it
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} else if (buffer_index < (MAX_INPUT_LEN - 1) && isprint(input_char)) {
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printf("%c", input_char);
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input_buffer[buffer_index] = input_char;
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buffer_index++;
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// update OLED with current input
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input_buffer[buffer_index] = '\0';
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display.refresh(input_buffer, g_last_echo);
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}
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}
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if (buffer_index > 0 && (time_us_64() - last_char_time) > TIMEOUT_US) {
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printf("\n--- Timeout Reached (5.0s silence) ---\n");
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echo_and_reset(input_buffer, &buffer_index, display);
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last_char_time = time_us_64();
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}
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// Advance marquee for last echoed text if needed
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size_t last_len = strlen(g_last_echo);
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uint64_t now_ms = time_us_64() / 1000;
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sleep_us(100);
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}
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printf("\nHost disconnected. Ending Echo Session.\n");
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}
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int main() {
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stdio_init_all();
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DisplayManager display;
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display.init();
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while (true) {
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wait_for_usb_connection();
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run_echo_session(display);
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}
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return 0;
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}
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