C64 IEC interface schematics for DE0 nano, DE1 or DE2 board

IEC interface components :

• 1 TTL 74LS06  six open collector buffer inverter
• 6 resistors 2 kOhms  

Gpio side : 

• connect to gpio_0 for DE0 Nano
• connect to gpio_1 for DE1 or DE2

IEC side :

• to IEC/SD board
• to 1541 drive din connectors (+5V not connected )