Lecture 13 (Lecture 14) - Embedded Linux

Question 1

STEPS TO SET A RASPBERRY PI

Answer 1

REFER TO SLIDES

Question 2

What is a router?

Answer 2

Ip-addresses are issues by router manually
Router (DHCP) will assign an IP address to Raspberry as well as Mac/PC

Question 3

What is a peer to peer connection?

Answer 3

Ip addresses ahve to be set
Using our R&A extended version of Raspbian, the Rasp will default to IP address:
10.0.0.1 on LAN if no DHCP router is detected, and to 10.1.1.1 on WLAN.
Note: this does not work with standard Raspbian
So e.g. for LAN connection:
* Set Mac/PC IP address manually to 10.0.0.2 (matching first 3
bytes).
* Set Mac/PC netmask to 255.255.255.0

Question 4

What is internet sharing?

Answer 4

Refer to slides

Question 5

What is remote access?

Answer 5

Refer to slides

Question 6

What are some of the programming tools used?

Answer 6

Editor - For entering program source code
Assembler - Translate assembly program to machine program and to display error messages
Emulator - Simulates program execution
Loader - Upload machine code to embedded system
Debugger:
- Allows to stop program in mid-execution
- Allows to examine current register and memory contents
- Allows to set breakpoints: stop program at an instruction
- Allows to single-step through program
- Very helpful in testing and debugging of a program

Question 7

What is the Operating System for embedded systems?

Answer 7

• Not always necessary for embedded systems
• Small embedded systems have no OS, but sometimes small, compact collection of routines in ROM
• Advanced or high-performance embedded systems such as ARM / Raspberry Pi do require an operating system
• Typically when an embedded system has complex interfaces, such as LAN or USB, it requires an operating system

Question 8

If there is no operating system…

Answer 8

• Your program is the only thing running on the microcontroller
• Your program must have an endless loop, it must never terminate

Question 9

If there is an operating system…

Answer 9

• Your program is only one of many running on the system
• Your program is called from the operating system as a subroutine
• Your program must not have an endless loop, it must always terminate
• The endless loop is in the operating system

Question 10

What are the UNIX file functions

Answer 10

Refer to slides

Question 11

What is an IP address?

Answer 11

Each device on an Ethernet LAN requires an IP address (Internet Protocol) as identifier for sending/receiving
messages
* IPv4 vs. IPv6 We will only use IPv4 here
* Usually an IP address will be automatically assigned to the
device (Raspberry Pi) when plugging it into a router
(using DHCP, dynamic host configuration protocol,
typical address: 192.168.2.7)
* When directly linking two devices (e.g. a Mac/PC and
Raspberry)
using a cross-cable (regular cable is fine for Raspberry), then
both systems have to be set to addresses in the same prefix
range, e.g. Raspberry is 10.0.0.1, Mac/PC is 10.0.0.2