Add photos and datasheet; correct wiring and protocol docs

The 20L203 input is RS-232 (reference build uses a MAX3232), it runs on
5-24 V, and it boots in non-scrolling overwrite mode.

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

examples/samsung-vfd.yaml

@@ -3,14 +3,13 @@
 # Copy this file into your ESPHome config folder (and add the keys below to
 # your secrets.yaml), or use it as a reference for your own device config.
 #
-# Wiring (display is 5V TTL serial, 9600 8N1):
-#   display RX  <-  ESP32 GPIO17 (TX)
-#   display GND <-> ESP32 GND
-#   display 5V  <-  5V supply (the display needs more current than the ESP32 regulator can give)
+# Wiring (3-pin connector on the display, 9600 8N1):
+#   pin 1 VCC <-  5-24V supply, up to 1.2A at 5V (not the ESP32 regulator)
+#   pin 2 RXD <-  MAX3232 T1OUT  <-  T1IN  <-  ESP32 GPIO17 (TX)
+#   pin 3 GND <-> supply GND, MAX3232 GND and ESP32 GND
 #
-# To drive the display from GPIO1 (TX0, the USB serial pin) instead, set
-# `tx_pin: GPIO1` below and `baud_rate: 0` under `logger:` so log output does
-# not end up on the display.
+# RXD is an RS-232 input. Without a MAX3232, wire GPIO17 straight to RXD and
+# set `inverted: true` under uart.
 
 esphome:
   name: samsung-vfd
@@ -81,7 +80,9 @@ time:
 
 uart:
   id: uart_vfd
-  tx_pin: GPIO17
+  tx_pin:
+    number: GPIO17
+    inverted: false   # true when wired directly, without a MAX3232
   baud_rate: 9600
   # The display is output-only for us; no rx_pin needed.
 
@@ -90,8 +91,7 @@ samsung_vfd:
   uart_id: uart_vfd
   cols: 20
   rows: 2
-  # Lines are padded to 20 chars and the display wraps by itself. Set to true
-  # only if line 2 ends up on the wrong row (sends CR LF between the lines).
+  # Lines are padded to 20 chars and the display wraps to line 2 by itself.
   send_newlines: false
 
 # Bottom line shows the SNTP clock every second, except while a status banner is up.