Add constant for max message length

ports/stm32/boards/Passport/modules/constants.py

@@ -39,3 +39,6 @@ MAX_ACCOUNT_NAME_LEN = 20
 MAX_MULTISIG_NAME_LEN = 20
 
 DEFAULT_ACCOUNT_ENTRY = {'name': 'Primary', 'acct_num': 0}
+
+# Maximum amount of characters in a text entry screen
+MAX_MESSAGE_LEN = 64

ports/stm32/boards/Passport/modules/display.py

@@ -195,10 +195,11 @@ class Display:
     def text_input(self, x, y, msg, font=FontSmall, invert=0, cursor_pos=None, visible_spaces=False, fixed_spacing=None, cursor_shape='line'):
         from ux import word_wrap
         from utils import split_by_char_size
+        from constants import MAX_MESSAGE_LEN
 
-        # Maximum message size is 64 characters
-        if len(msg) >= 64:
-            msg = msg[:64]
+        # Maximum message size is MAX_MESSAGE_LEN (64) characters
+        if len(msg) >= MAX_MESSAGE_LEN:
+            msg = msg[:MAX_MESSAGE_LEN]
 
         if hasattr(msg, 'readline'):
             lines = split_by_char_size(msg.getvalue(), font)