The DL1416 display firmware running on the PIC16F1459 takes input data from either the USB Interface or a TTL-level Serial input. The USB Interface appears as a CDC Class communications device to the host PC. The TTL-level Serial input runs at 57,600 baud. The DL1416 echoes all incoming serial data from either the USB or Serial input to a TTL-level serial output for connection to subsequent display boards.

ASCII characters are displayed directly. Lower case letters are converted to upper case letters by the display.

Some control characters and sequences have special meaning and can be used to control the display or the cursor position on the display.

   ^H - Backspace : backspace cursor on same line (no change at position 0)

   ^I - Tab : forward space cursor

   ^J - Line Feed : move cursor to next line (no change on last line)

   ^L - Form Feed : clear display

   ^M - Carriage Return : move cursor to position 0 on the current line

   ^N - Shift Out : set destination to shadow memory

   ^O - Shift In : set destination to display

   ^Q - DC1 : enable cursor (applies only when destination is display)

   ^R - DC2 : disable cursor (applies only when destination is display)

   ^S - DC3 : enable cursor blink (applies only when destination is display)

   ^T - DC4 : disable cursor blink (applies only when destination is display)

   ^V - SIDLE : Display firmware version

   ^Z - Substitute : Load shadow memory

   DEL - Delete : Change previous character to a blank and backspace

   ^[ - Escape : Set Cursor Position

      COL;ROW'H'  (special case: 'H' set to home (0,0)

The display has two memories. ^N and ^O control access to the two memories. The default memory is immediate display mode. Any received character data is immediately displayed. The second memory is called shadow memory and writing to it does not immediately change the display. ^N sets the destination to shadow memory. ^O sets the destination to immediate display mode. ^Z copies the shadow memory to immediate memory and updates the display. Two sets of cursor positions are maintained, one for each memory.