Update error message for unsupported option

src/boards/heltec_wireless_stick.h

@@ -97,11 +97,7 @@ const lmic_pinmap lmic_pins = {
     .rssi_cal = 10,
     .spi_freq = 8000000     /* 8 MHz */
 #endif    
-};
-
-#ifdef USE_DISPLAY
-    #error Onboard display is not supported because resolution is too low.
-#endif    
+}; 
 
 #ifdef USE_SERIAL
     HardwareSerial& serial = Serial;
@@ -112,6 +108,7 @@ const lmic_pinmap lmic_pins = {
 #endif
 
 #ifdef USE_DISPLAY
+    #error Invalid option: USE_DISPLAY. Onboard display is not supported because resolution is too low.
     // Create U8x8 instance for SSD1306 OLED display (no reset) using hardware I2C.
     U8X8_SSD1306_64X32_NONAME_HW_I2C display(/*rst*/ U8X8_PIN_NONE, /*scl*/ 15, /*sda*/ 4);
 #endif

src/boards/lopy4.h

@@ -13,7 +13,7 @@
  *  Description:  This Board has no onboard USB and no onboard display.
  *                Optionally an external display can be connected.
  *                Has onboard LED but this is a special WS2812 RGB LED which requires
- *                a separate library and is currently not supported in LMIC-node.
+ *                a separate library and is currently not supported by LMIC-node.
  *
  *                The standard SPI pins defined in the BSP do not match the 
  *                GPIO pins that the SX1276 LoRa chip is connected to.
@@ -134,9 +134,7 @@ const lmic_pinmap lmic_pins = {
 #endif    
 
 #ifdef USE_LED
-    // Using onboard LED is currently not supported for this board
-    // because it is not a standard LED but a WS2812 RGB LED.
-    #error "USE_LED is not supported for this board."
+    #error "Invalid option: USE_LED. Onboard WS2812 RGB LED is not supported."
 #endif
 
 #ifdef USE_DISPLAY

src/boards/nodemcuv2.h

@@ -109,7 +109,7 @@ const lmic_pinmap lmic_pins = {
 #endif
 
 #ifdef USE_DISPLAY
-    #error "Display and I2C interface cannot be used with this board due to shortage of GPIO pins."
+    #error "Invalid option: USE_DISPLAY. I2C and display are not supported due to shortage of available GPIO pins."
 #endif
 
 

src/boards/pro8mhzatmega328.h

@@ -11,6 +11,7 @@
  * 
  *  Description:  This Board has no onboard USB and no onboard display.
  *                Optionally an external display can be connected.
+ *                Onboard LED cannot be used due to hardware conflict.
  * 
  *                For firmware upload and serial monitor use a USB to serial 
  *                adapter that supports DTR (for automatic firmware upload).
@@ -27,7 +28,6 @@
  *                ----                ----  
  *                LED   <――――――――――>  13  (LED_BUILTIN) (SCK) Active-high, 
  *                                        Useless, shared with SCK.
- *                LED_EXTERNAL <--->   6  Optional external LED.
  * 
  *                I2C [display]       GPIO  
  *                ---                 ---- 
@@ -95,16 +95,9 @@ const lmic_pinmap lmic_pins = {
     HardwareSerial& serial = Serial;
 #endif  
 
-#define LED_EXTERNAL 6
-// #define LED LED_EXTERNAL
-#define LED LED_BUILTIN
-
 #ifdef USE_LED
-    #if LED == LED_BUILTIN
-        #error Cannot use LED_BUILTIN because it conflicts with SPI (alternative: use external LED).
-    #else
-        EasyLed led(LED, EasyLed::ActiveLevel::High);
-    #endif
+    #error Invalid option: USE_LED. Onboard LED cannot be used due to hardware conflict.
+    // EasyLed led(<external LED GPIO>, EasyLed::ActiveLevel::Low);
 #endif
 
 #ifdef USE_DISPLAY

src/boards/ttgo_lora32_v1.h

@@ -19,11 +19,12 @@
  *                the I2C Wire object is explicitly initialized with the
  *                correct pins (see boardInit() below).
  * 
- *                LED_BUILTIN is defined in BSP but schematic diagram and
- *                and pinout diagram show no onboard user LED.
- *                Based on documentation USE_LED is not supported for this board.
+ *                Schematic diagram and and pinout diagram show no onboard 
+ *                user programmable LED while LED_BUILTIN is defined in BSP.
+ *                Definition in BSP is incorrect.
  * 
  *                OLED_RST and LORA_RST are defined in BSP but neither is connected to GPIO.
+ *                Definitions in BSP are incorrect.               
  * 
  *                CONNECTIONS AND PIN DEFINITIONS:
  *                
@@ -32,8 +33,7 @@
  * 
  *                Leds                GPIO 
  *                ----                ----
- *                LED   <――――――――――>  2  Defined in BSP as LED_BUILTIN, however:
- *                                       According to documentation this board has no LED.
+ *                LED                 -            Incorrectly defined in BSP as LED_BUILTIN (2).
  * 
  *                I2C/Display         GPIO
  *                ---                 ---- 
@@ -110,8 +110,8 @@ const lmic_pinmap lmic_pins = {
 #endif  
 
 #ifdef USE_LED
-    #error Unknown if this board has a user LED therefore USE_LED is not supported.
-    // EasyLed led(LED_BUILTIN, EasyLed::ActiveLevel::Low);  // Or active-high?
+    #error Invalid option: USE_LED. This board has no onboard user LED.
+    // EasyLed led(<external LED GPIO>, EasyLed::ActiveLevel::Low);
 #endif
 
 #ifdef USE_DISPLAY

src/boards/ttgo_lora32_v2.h

@@ -93,7 +93,7 @@ const lmic_pinmap lmic_pins = {
 };
 
 #if defined(USE_DISPLAY) && defined(USE_LED) && LED_PIN == LED_ONBOARD
-    #error USE_DISPLAY and USE_LED cannot be used together for onboard LED
+    #error Invalid option: USE_DISPLAY and USE_LED cannot be used together.
 #endif    
 
 #ifdef USE_SERIAL