Arduino platforms (week 2/3)

Question 1

ATMega controllers-What is their memory organisations?

Answer 1

AVR architecture has two main memories:
CODE AND DATA MEMORY (HARVARD ARCHITECTURE)

Question 2

ATMega controllers-What is the CODE memory?

Answer 2

The code memory (Flash memory) structure: 256k byte of memory. 128k locations. 16-bit stored in each location.

Question 3

ATMega controllers-What is the DATA memory?

Answer 3

Data memory (RAM memory) has a structure with:
- 32 locations to store register file
-64 locations for standard I/O memory
-416 locations for extended I/O memory
-8192 locations for internal RAM

Question 4

Memory organisation in ATMega controllers. How the code is executed?

Answer 4

We set the right bits in the right registers

Question 5

What would look like a user Arduino code at low level ? what are the PIN REGISTERS ?

Answer 5

DDRx -> set corresponding pin, input=0, output=1
PORTx -> read/write value of the voltage on corresponding pin. (low /high)
PINx -> holds current state of input pin.Get current logical level

Question 6

Why is there no need in reading an input pin?

Answer 6

Because it is directly copied in corresponding PORTx register.

Question 7

How to write a digital output with registers ?

Answer 7

Set/clear the corresponding bit in the PORTx register.
State of corresponding physical pin will change accordingly.

Question 7

What is the timing of a program?

Answer 7

The AVR CPU is driven by CPU clock, generated from selected clock for the chip.

Question 8

What is the difference between coding in low-level and high-level languages?

Answer 8

In high-level code, it is hard to predict running time.
In low-level, every line corresponds to one instruction, highly accurate control of time.