The Harvard architecture for micro-controllers added which additional bus?

The Harvard architecture for microcontrollers added an additional bus called the Instruction bus. This is because in the Harvard architecture, the data and instruction memory are separate, and each have their own dedicated bus. The Instruction bus is used specifically for fetching instructions from the instruction memory, allowing for more efficient and simultaneous fetching and execution of instructions. By having a dedicated Instruction bus, the microcontroller can fetch instructions while simultaneously accessing data, leading to improved performance and faster execution of programs.