Introduction - If you have any usage issues, please Google them yourself
Proteus6.7 is currently the best single-chip peripheral device simulation tools, really good. Simulation Series 51 can be, AVR, PIC, such as commonly used in MCU and its peripheral circuits (such as the LCD, RAM, ROM, keyboard, motor, LED, AD/DA, some SPI devices, in fact, part of IIC devices ,...) Proteus with Multisim to compare like with like, but it can simulation MCU!