Address Data LCD RAM 8K SRAM Output Demux 74HC138 Keypad Input 74HC244 Inverters 74HC04 OR Gates 74HC32 PC Bits 1-0 74HC193 EEPROM 32K EEPROM Reg Bits 15-12 74HC670 Reg Bits 11-8 74HC670 Reg Bits 7-4 74HC670 Reg Bits 3-0 74HC670 Reg Selector 74HC574 Input Demux 74HC138 Instruction 74HC574 Buffer 74HC574 D3-D0 DB7-DB4 Q3-Q0 AB15-AB12 D3-D0 DB3-DB0 Q3-Q0 AB11-AB8 D3-D0 DB7-DB4 Q3-Q0 AB7-AB4 D3-D0 DB3-DB0 Q3-Q0 AB3-AB0 IO7-IO0 DB7-DB0 Q1-Q0 RA1-RA0 Q3-Q2 RA1-RA0 Q5-Q4 RA1-RA0 RA1-RA7 D7-D0 DB7-DB0 Q7-Q6 W1-W0 W1-W0 W1-W0 W1-W0 D7-D0 DB7-DB0 Q2-Q0 A2-A0 Q4-Q3 A1-A0 Q5 OE Y0 WE WE Y1 WE WE Y2 CLOCK Y3 CLOCK Y4 CLOCK Y5 WE D7-D0 DB7-DB0 Q7-Q0 IO7-IO0 DB7-DB0 A12-A0 AD12-AD0 Q2-Q1 A14-A13 Q0 1A Q1 1B Q0 2A Q1 1A A12-A0 AB12-AB0 IO7-IO0 DB7-DB0 Y0 OE Y1 OE Y2 OE Y3 2A Q7-Q0 DB7-DB0 1Y 2B 3Y 3A 2Y 3B 1Y 3A 1Y CLOCK 2Y CS2 3Y OE