update _write_char

adafruit_thermal_printer/thermal_printer.py

@@ -196,12 +196,12 @@ def _wait_timeout(self) -> None:
         while time.monotonic() < self._resume:
             pass
 
-    def _write_char(self, char: str) -> None:
+    def _write_char(self, char: str, *, encoding: str = "utf-8") -> None:
         # Write a single character to the printer.
         if char == "\r":
             return  # Strip carriage returns by skipping them.
         self._wait_timeout()
-        self._uart.write(bytes(char, "ascii"))
+        self._uart.write(bytes(char, encoding))
         delay = self._byte_delay_s
         # Add extra delay for newlines or moving past the last column.
         if char == "\n" or self._column == self._max_column:
@@ -298,15 +298,21 @@ def reset(self) -> None:
         # ESC + 'D' + tab stop value list ending with null to terminate.
         self.send_command("\x1BD\x04\x08\x10\x14\x18\x1C\x00")
 
-    def print(self, text: str, end: Optional[str] = "\n") -> None:
+    def print(
+        self, text: str, end: Optional[str] = "\n", *, encoding: str = "utf-8"
+    ) -> None:
         """Print a line of text.  Optionally specify the end keyword to
         override the new line printed after the text (set to None to disable
-        the new line entirely).
+        the new line entirely). Optionally specify the encoding. Some
+        printers only accept the more restrictive encodings "cp437" and
+        "ascii".
+        Note: Encodings other than "utf-8" are not accepted by
+        microcontrollers.
         """
         for char in text:
-            self._write_char(char)
+            self._write_char(char, encoding=encoding)
         if end is not None:
-            self._write_char(end)
+            self._write_char(end, encoding=encoding)
 
     def print_barcode(self, text: str, barcode_type: int) -> None:
         """Print a barcode with the specified text/number (the meaning