Summary
Summary ALU, CPU, Registers and buses - SLR 1 OCR ALEVEL COMP SCI
- Module
- SLR 1 - Systems architecture
- Institution
- OCR
Notes regarding the alu, cpu, registers, and buses that follows the ocr alevel comp sci spec
[Show more]
Seller
Follow
Content preview
Topic: ALU, CU, registers and busesQuestions Notes
Control unit
Coordinates all activities of the CPU
Directs flow of data between CPU and other devices
Fetches next instruction, decodes it, executes it, stores the resulting
data back in memory or registers
Sends memory read and write request to main memory on the control
bus – and other command and control signals such as bus requests, bus
grants, interrupt requests
Makes extensive use of status registers and clock
Coordinates and communicates with all parts of the CPU (orange lines)
Program counter
Holds the address of the next instruction to be executed
This could be:
o Next instruction in a sequence of instructions
o Address to jump to if the current instruction is a command to
jump or a branch – this would be copied from the current
instruction register
Close relationship with MAR (Memory address register) - At start of
every fetch,decode,execute cycle, the address held in PC Is copied to
MAR.
Memory address register (MAR)
Holds address of memory location from which:
o Data
o Instruction
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller mythicalphilosopher. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £4.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
56326 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now