more progress on UART read

c/uart_sim_device.c

@@ -6,6 +6,7 @@
 #include <stdbool.h>
 
 static volatile bool ctrl_c_received = false;
+static char last_char = '\0';
 
 void sigint_handler(int sig_num) {
     ctrl_c_received = true;
@@ -37,8 +38,10 @@ void restore_terminal() {
 }
 
 char get_char_from_terminal() {
-    char c = getchar();
-    return c;
+    if (is_char_available()) {
+        last_char = getchar();  // Update last_char if new character is available
+    }
+    return last_char;  // Return the last available character (or '\0' initially)
 }
 
 void write_char_to_terminal(char chr) {
@@ -71,4 +74,4 @@ int is_char_available() {
         // No character available
         return 0;
     }
-}
+}