make LETTTER_OFF return values that match param indices range

7 years ago · e6e3132f79
1 changed files with 1 additions and 1 deletions
--- a/Marlin/gcode.h
+++ b/Marlin/gcode.h
@ -104,7 +104,7 @@ public:
  // Index so that 'X' falls on index 24
  #define PARAM_IND(N)  ((N) >> 3)
  #define PARAM_BIT(N)  ((N) & 0x7)
-  #define LETTER_OFF(N) ((N) - 'A' + 1)
+  #define LETTER_OFF(N) ((N) - 'A')
  #define LETTER_IND(N) PARAM_IND(LETTER_OFF(N))
  #define LETTER_BIT(N) PARAM_BIT(LETTER_OFF(N))