Address bus
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. What does the address bus carry?
2. In which direction does the address bus send signals?
3. Which register supplies the address that is placed on the address bus?
4. Which statement about the address bus is correct?
5. The CPU wants to read the instruction stored at address 100. What is sent along the address bus?
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1address bus | AThe path an address takes when the CPU wants to access a memory location | |
| 2MAR → address bus → RAM | BThe address bus is one-way and goes from the CPU to RAM, not from RAM to the CPU. | |
| 3The address bus is one-way: addresses only travel from the CPU to memory, never back | CMAR = 0042, address bus carries 0042 | |
| 4The address in the MAR is the value placed on the address bus | DThe address bus carries addresses, not data. Data travels along the data bus. | |
| 5The address bus carries data from RAM to the CPU | ECPU → address bus → RAM | |
| 6RAM → address bus → CPU | FA one-way bus that carries the address of a memory location from the CPU to RAM |
C
Definitions
address bus
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
Address on the bus comes from the ___
2.
Address bus: CPU → ___
3.
The address bus carries _________, not data
4.
Address bus direction: _______
5.
MAR ← PC
___________ ← MAR
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
MAR holds address 0042
B
CPU puts it on address bus
C
Address bus carries it one way
D
RAM sends the address to CPU
Question 2
A
Address bus: one-way
B
Direction: CPU to RAM
C
Carries: memory addresses
D
Sender: MDR
Question 3
A
CPU needs data at address 7
B
MAR <- 7
C
Address bus sends data to RAM
D
MDR <- data from RAM
Question 4
A
Address bus: RAM to CPU
B
It is a one-way bus
C
The MAR sends the address
Question 5
A
PC holds next address
B
MDR <- PC
C
Address bus carries MAR
Answer Key
Address bus
Section A: Quick Questions
Q1
A — The address of a memory location
Q2
B — One way: from the CPU to memory
Q3
B — Memory address register (MAR)
Q4
A — It carries addresses, not data
Q5
A — The address 100
Section B: Match the Pairs
Q1
address bus → A one-way bus that carries the address of a memory location from the CPU to RAM
Q2
MAR → address bus → RAM → The path an address takes when the CPU wants to access a memory location
Q3
The address bus is one-way: addresses only travel from the CPU to memory, never back → CPU → address bus → RAM
Q4
The address in the MAR is the value placed on the address bus → MAR = 0042, address bus carries 0042
Q5
The address bus carries data from RAM to the CPU → The address bus carries addresses, not data. Data travels along the data bus.
Q6
RAM → address bus → CPU → The address bus is one-way and goes from the CPU to RAM, not from RAM to the CPU.
Section C: Definitions
Q1
address bus — A one-way bus that carries the address of a memory location from the CPU (sent from the MAR) to RAM. It carries addresses, not data.Section D: Fill in the Blanks
Q1
Address on the bus comes from the MARQ2
Address bus: CPU → RAMQ3
The address bus carries addresses, not dataQ4
Address bus direction: one-wayQ5
MAR ← PC
address bus ← MARSection E: Spot the Error
Q1
D — The address bus is one-way, from the CPU to RAM. RAM receives the address, so line 4 should be 'RAM receives the address'.
Q2
D — The address sent on the address bus comes from the MAR. The MDR holds data being transferred, so it should be 'Sender: MAR'.
Q3
C — The address bus carries the address (7), not data. The line should be 'Address bus carries 7 to RAM'.
Q4
A — The address bus carries addresses from the CPU to RAM, never the other way. It should be 'Address bus: CPU to RAM'.
Q5
B — The address is copied from the PC into the MAR, which then sends it on the address bus. It should be 'MAR <- PC'.