Download the 1601A datasheet.
Pinning LCD display 1601A:
Pin no. Symbol Function
1 Vss GND
2 Vdd + 5V
3 Vo Contrast Adjustment
4 RS H/L Register select signal
5 RW H/L Read/write signal
6 E H->L Enable signal
7 DB0 H/L Data bus line
8 DB1 H/L Data bus line
9 DB2 H/L Data bus line
10 DB3 H/L Data bus line
11 DB4 H/L Data bus line
12 DB5 H/L Data bus line
13 DB6 H/L Data bus line
14 DB7 H/L Data bus line
15 A 4.2 Volt for LED
16 K Power for supply B/L (0V)
The CFAH1601AYYBJP is an LCD display with 5x8 character-dot space and 16 character positions and LED (yellow) backlite. It has an industry-standard HD44780 compatible controller chip on the back. An 8-bit or 4-bit parallel interface, and a very wide viewing angle. It operates on +5 Volt, and consumes only 1.2 mA which makes it good for battery usage, but the backlite-LED uses 130 mA@4.1V, so make e.g. a button which activates the backlite, and then automatically let it switch off after three seconds. What also can be done with this display is making your own characters (up to 8 max. by internal RAM, called CGRAM = Character Generator RAM) The ROM consists of the complete ASCII character-set, and also the Japanese/Greek characters, a total of 192 character locations. When using the 4bit interface, you must transmit 2 * 4-bit for each instruction. To let the display operate, it first must be initialized (init procedure) (don't forget to adjust the contrast (0.8V), else you won't see nothing. Use a 10k potmeter) I will show both 4- and 8-bit interfaces. 4-bit because it saves 4 i/o's of the microcontroller. 8-bit because it's shorter code. Here all features this LCD has:

  • Interface with either 4-bit or 8-bit microcontroller.
  • Character generator ROM: 192 different 5 x 8 dot-matrix character patterns.
  • Character generator RAM: 8 different user programmed 5 x 8 dotmatrix patterns.
  • Display data ROM and character generator RAM may be accessed by the microcontroller.
  • Numerous instructions: Clear Display, Cursor Home, Display ON/OFF, Cursor ON/OFF, Blink Character, Cursor Shift, Display Shift.
  • Built-in reset circuit is triggered at power ON.
  • Built-in oscillator (270 kHz)


    • Next a diagram (4-bit interface) of a CFAH1601AYYBJP LCD display connected to an AT90S1200 microcontroller:

    AT90S1200 <-> 16x1 LCD display (4-bit interface)
    Part list:

    1x AT90S1200
    1x 1x16 LCD (HD44780)
    1x 78L05
    1x 4 MHz resonator
    1x 47uF/16V
    2x 100n multilayer
    1x 100n MKH
    1x 10k pot
    1x 10k
    Display text on a 1x16 LCDScrolling text on a 1x16 LCD display

    Displaying text and a scrolling message