This deep dive covers Deep Dive: How MAR and MDR Work Together within MAR, MDR & Registers for GCSE Computer Science. Revise MAR, MDR & Registers in 3.4 Computer Systems for GCSE Computer Science with 15 exam-style questions and 10 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 3 of 8 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Deep Dive: How MAR and MDR Work Together
When the CPU needs data from memory, here's exactly what happens:
- CPU puts the memory address into the MAR
- MAR sends this address along the Address Bus to memory
- Memory finds the location and reads what's stored there
- The data travels back along the Data Bus to the MDR
- CPU can now use the data from MDR
Writing works in reverse: CPU puts address in MAR, puts data to write in MDR, sends both to memory. Memory stores the MDR contents at the MAR address.
Practice questions for MAR, MDR & Registers
What does MAR stand for?
Explain the difference between the MAR and the MDR.