Support every datasheet command and map text to the CG-ROM fonts

- Brightness, blink, screen on/off, annunciators, cursor control, display
  modes, user-defined characters, code table, international charset,
  peripheral select, self-test, raw writes and reinit
- UTF-8 text is encoded with the selected code table (tables generated
  from Python codecs by tools/gen_charmaps.py), falling back to
  accent-stripping
- Settings survive reinit and the self-test
- Example gains brightness select and display switch, and uses the git
  source on mangavalk.com

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

examples/samsung-vfd.yaml

@@ -21,7 +21,7 @@ esphome:
           id: vfd
       - samsung_vfd.print:
           id: vfd
-          text: "Hello World!"
+          text: "Hello World! ~"  # "~" is the heart defined below
           centered: true
       - delay: 3s
       # Bring back the last text Home Assistant set for the top line.
@@ -31,7 +31,10 @@ esphome:
           text: !lambda "return id(vfd_line1).state;"
 
 external_components:
-  - source: github://REPO_OWNER/REPO_NAME@main
+  - source:
+      type: git
+      url: https://mangavalk.com/mangavalk/esphome-samsung-vfd
+      ref: main
     components: [samsung_vfd]
     refresh: 1d
   # While developing the component, use the checkout instead:
@@ -78,12 +81,14 @@ time:
       - 0.pool.ntp.org
       - 1.pool.ntp.org
 
+# Must match the display's jumpers; all open (factory default) = 9600, no parity.
 uart:
   id: uart_vfd
   tx_pin:
     number: GPIO17
     inverted: false   # true when wired directly, without a MAX3232
   baud_rate: 9600
+  parity: NONE
   # The display is output-only for us; no rx_pin needed.
 
 samsung_vfd:
@@ -91,8 +96,20 @@ samsung_vfd:
   uart_id: uart_vfd
   cols: 20
   rows: 2
-  # Lines are padded to 20 chars and the display wraps to line 2 by itself.
-  send_newlines: false
+  brightness: 100%
+  code_table: PC437           # glyphs for é, ü, °, ½, box drawing ... (match jumpers 6-8)
+  international_charset: USA
+  # Up to 4 custom glyphs, replacing a printable ASCII character you don't use.
+  user_characters:
+    - code: "~"
+      pattern:
+        - ".#.#."
+        - "#####"
+        - "#####"
+        - "#####"
+        - ".###."
+        - "..#.."
+        - "....."
 
 # Bottom line shows the SNTP clock every second, except while a status banner is up.
 interval:
@@ -171,3 +188,31 @@ text:
               - script.execute:
                   id: show_status
                   msg: !lambda "return x;"
+
+# Brightness (4 levels) and power from Home Assistant.
+select:
+  - platform: template
+    name: "VFD brightness"
+    icon: mdi:brightness-6
+    optimistic: true
+    restore_value: true
+    options: ["40%", "60%", "80%", "100%"]
+    initial_option: "100%"
+    on_value:
+      then:
+        - samsung_vfd.set_brightness:
+            id: vfd
+            brightness: !lambda "return (i + 2) * 0.2f;"
+
+switch:
+  - platform: template
+    name: "VFD display"
+    icon: mdi:monitor
+    optimistic: true
+    restore_mode: RESTORE_DEFAULT_ON
+    turn_on_action:
+      - samsung_vfd.turn_on:
+          id: vfd
+    turn_off_action:
+      - samsung_vfd.turn_off:
+          id: vfd