Question

Explain the various steps involved in designing a custom single-purpose processor.

Answer 1

A single purpose processor is a digital circuit designed to execute exactly one program. It is also known as co-processor, accelerator or peripheral.

• It contains only the components needed to executes a single program.
  
• It has no program memory.
  
• The datapath contains only the essential components for this program i.e. 2 registers and one adder.
  
• Since the processor only executes this one program we hardwire the programs instructions directly into the control logic and use a state register to step through those instructions, so no program memory is necessary.
  

Design metric advantages or benefits:

• Size and power may be small.
  
• Performance may be fast.
  
• Unit cost may be low for large quantities.
  

Design matric disadvantages or demerits:-

• Design time and NRE cost may be high.
  
• Flexibility is low.
  
• Unit cost high for small quantities.
  
• Performance may not match general-purpose processors for same applications.