An ordinary LCD panel can be driven from a microcontroller using either four or eight data wires. In addition to these, an RS signal is needed to distinguish data from commands, and an E signal is needed to clock the data into the panel. This large total number of connections is unfortunate in our application because it ties up a number of port pins that could be used for other purposes.
Resistors
R1 = 10kΩ (SMD 805)
P1 = 10kΩ preset (SMD)
Capacitors
C1 = 10µF 6.3V (SMD)
Semiconductors
D1 = BAS70 (SMD)
IC1 = 4094 (SMD SO16)
Miscellaneous
K1 = 4-way SIL pinheader
LCD1 = LC Display 4x20 characters (HD44780 compatible)
14-way SIL pinheader
PCB with SMDs premounted, incl. all parts and 4x20 LCD; Elektor Shop # 071035-93