• 990.014 MuIn LCD - Datasheet [EN]

    MuIN LCD Board is a multi-interface LCD display controller compatible with HD44780 chipset and similars.

    Main Features

    • Available connections modes: USB, UART, RS485
    • External power supply or by USB port
    • Backlight control
    • Commands set compatible with Matrix Orbital displays
    • Xbee support on-board
    • Piezo-speaker on board with variable tones
    • General purpose inputs (can be used for button connection)
    • Up to 5 A/D channels with 10 bit resolution
    • USB Bootloader for easy software update


    • Generic data display
    • Remote consolle
    • Remote alphanumeric terminal

    MuIN LCD doesn't need to be programmed! It operates like a serial remote terminal: data received are displayed directly on the LCD and the carriage return is automatic at the end of a row. A set of useful commands is available to get the full control of the board.

    The MuIN LCD is not only capable to display simple text! Following command sets are available:

    • Speaker: it can play a 4KHz standard tone or an user-defined tone
    • Backlight control: the backlight can turned off or on with intensity adjustment
    • Up to 6 general purpose inputs, TTL and CMOS compatible
    • Up to 5 A/D channels with 10 bit resolution
    • Xbee slot: can be used for the connection of other compatible boards

    Full command list is on the user manual

    Technical specifications

    • Power supply: from 6 to 9Vdc
    • Current consumption: 60mA (backlight off) - 200mA (backlight on at full intensity)
    • USB port 2.0 full speed, CDC device with serial port emulation, XP/Vista/Win7 compatible with provided driver (can be downloaded below). Linux uses native driver (Linux could be need an update)
    • RS485 port with line terminator, 120Ohms, jumper-selectable bias
    • UART TTL and CMOS 3.3V compatible, TTL level output

    Only one serial communication method can be selected by using the dedicate jumper:

    USB port doesn't need any selection and can be used also for LCD and XBee power supply. The backlight intensity can be adjusted by software, the contrast is adjusted by a trimmer.

    On-board there are two 22Ohm resistors used to limitate the LCD backlight current, if your display is already equipped with current-limitation resistors, the on-board resistors can be excluded by soldering a jumper for each resistor in order to obtain the right light intensity.

    Display connector pinout

    The display connector follows the standard used by the most of HD44780-based LCD Display. Only 4 data line are used (4bit mode):

    • GND: common ground
    • V+: 5Vdc power supply
    • Vc: contrast adjustment
    • RS: register select
    • RW: Read/Write
    • EN: Enable
    • D4: data bus, bit 4
    • D5: data bus, bit 5
    • D6: data bus, bit 6
    • D7: data bus, bit 7
    • A: backlight led's anode (+)
    • K: backlight led's cathode (-)

    Warning: be sure your display have the same pinout or both the MuIN LCD and LCD display will be damaged!

    UART connector pinout

    • +5V: 5Vdc out, 100mA MAX
    • Rx: serial data in
    • Tx: serial data out
    • GND: common ground

    RS485 connector pinout

    • A: 'A' terminal for RS485
    • B: 'B' terminal for RS485

    Soldering Jumpers

    • P+: Positive bias RS485 (default: open)
    • P-: Negative bias RS485 (default: open)
    • TE: RS485 line terminator (default: open)
    • SPK EN.: Speaker enable (default: closed)

    Jumpers for function selection
    Serial port

    • 485 : serial communication on RS485
    • UART: serial communication on UART
    • Xbee: serial communication on XBee

    Power Supply

    • Xbee: enables XBee power supply by USB or by external power supply (leave this
      jumper open, if XBee is not used, to save some mA's)
    • Logic: enables display power supply by USB or by external power supply


    • closing this jumper performs an hardware-reset

    • RSSI: is turned on on Xbee data receive
    • ASSOC: flashes when XBee is ready
    • L1: slow flash indicates status ok, full turned on if MuIN is busy
    • L2: flashes when data are received or during command execution

    L1 high frequency flash indicates a permanent error. In this case the board need a reset using the dedicate reset jumper