Volex TTX2000 S Issue 1.2: Routine at 1C86

1C86: display_message: Display telesoftware error and prompt for input.

Used by the routine at telesoftware_main.
display_message	1C86	CALL write_header_message	Display the message at address in DE
	1C89	CALL display_header_row	Display the message at address in DE
get_y_n	1C8C	CALL get_keypress	Get a keypress
	1C8F	CP $4E	If 'N' reset to START
	1C91	JP Z,START	If 'N' reset to START
	1C94	CP $59	If 'Y' jump back to start_download, else loop back to get_y_n
	1C96	JR NZ,get_y_n
	1C98	JP start_download