BlackPill F401CC: add USER_BTN on PA0

Note this user button is not available on all revisions of this board

Fixes stm32duino#1144

Signed-off-by: Alexandre Bourdiol <[email protected]>

Author: ABOSTM

Diff for: variants/STM32F4xx/F401CC(F-U-Y)_F401C(B-D-E)(U-Y)/variant_BLACKPILL_F401CC.h

@@ -81,7 +81,8 @@
 
 // On-board user button
 #ifndef USER_BTN
-  #define USER_BTN              ND
+  // User button is not available on all revision of this board
+  #define USER_BTN              PA0
 #endif
 
 // SPI definitions