1. Course on Embedded Systems Introduction
Held at the University of Cape Coast
Winter Semester 2017
Lecture 1
Uli Raich

2. Introduction What should I introduce? Introduce myself
Introduce the course material
Why did you come to this course?
What do you expect?
This course is somehow different from other computing courses. In what way?
Did you learn about Linux? Why do I ask?

3. Introduce myself Dr. Ernst Ulrich Raich short: Uli
PhD in Physics (not computer science!) but 4 years of IT studies without diploma.
Married, 3 adult children
Staff member of CERN
Teaching (short courses) since 1980
Never taught a full university course!
Ask me whatever you want to know!

4. Difference to other Courses
Standard course:
During the semester:
Professor works, trying to explain his subject
Student sleeps, trying to recover from last night’s party
End of semester
Professor takes revenge through examinations
Student tries to catch up what he missed during the semester
This course:
Two hours of lectures per week, where the professor works
3 hours per week lab sessions (can be extended) where the student works!
If the student sleeps during the lectures the professor finds out latest during the lab session the same week.
If you don’t understand things during the lecture, ask immediately! Otherwise you will have trouble during the lab session!

5. Introduce the course Definition from Wikipedia: What is a computer?
A computer is a device that can be instructed to carry out arbitrary sequences of arithmetic or logical operations automatically. The ability of computers to follow generalized sets of operations, called programs, enable them to perform an extremely wide range of tasks.

6. A Computer
but ...what about this?
...or this ?
This is a computer !

7. Cost of a computer
When I was a student the university had 1 mainframe computer. Cost several 100k$
During my thesis I used a mini computer which was much cheaper (~80 k$) including 1 serial terminal Mbyte hard disk.

8. My first computer
The first computer I bought costed 1500 $ I got a PCB, a keyboard (without case) and a sac full of electronics to be soldered by the user (no hard disk, black and white TV as screen replacement, programmed in Basic
Programs were stored on audio casettes
This is the luxury version!
Cost: ~ 1500 US$

9. First PC My first PC looked a bit like this: It had
a huge 512 Mbyte hard disk
A floppy disk drive
512 Mbytes of RAM
Screen resolution 1024x768
The Linux system was loaded with 40! floppy disks
All screen parameters (timings!) had do be known to configure the driver
Cost: ~ 1500 $US

10. My current PC Processor 64 bits Intel I5 quad core
Screen: 15” 1920x1080
16 Gbytes RAM
128 Gbytes SSD
1 TB internal HD
1.5 TB external USB-3 HD
Cost: ~ 700 $US

11. My current computer
These are the specs of my current laptop for ~ 600 $:

12. Other computers I own
My tablet cost ~ 70 US$. Computing power by far exceeds that of the PDP-11 mini computer. Idem for RAM and disk size
The Raspberry Pi, which we use for the lab costs 40 US$. 32 Gbyte micro SD card must be added. A full Linux OS is installed on the device.
The Arduino Nano, which I used in a small robot project at UCC costs US$. This has no OS but can be programmed using a cross compiler and firmware download through USB. Programming in C or C++
Most embedded systems used in TV sets, coffee machines, washing machines, cars … cost less the 1$. Already 10 years ago a Mercedes car used more than 60 computers.
It is cheaper in almost all cases to use programmed logic over hardwired logic and it is definitively more flexible.

13. Booting a PC The boot sequence is essentially this one:
On reset the PC executes code in its ROM (BIOS or EFI) to initialize hardware
The boot sector is loaded from disk and executed
The kernel is loaded and executed
Additional programs are loaded (e.g. a shell)

14. Booting a high end embedded system
On embedded systems every processor has its own way to boot. However, there are some similarities:
After reset the processor executes a very short program in on-chip ROM
A small boot loader is loaded into on-chip memory and executed
The RAM memory controller, flash controller … are initialized
The secondary boot loader is transferred into the now available RAM
Boot loader gets the OS kernel from flash (can be a micro SD card) and executes it
From now on→ similar to a PC

15. Booting a low end embedded processor
The system uses a dedicated program and has no OS.
The program is developed on a different machine (cross-development) and transferred into the target system flash.
On reset the flash program is directly executed

16. Native versus cross development
The embedded system is often far less powerful than a PC
Compiling programs is much faster on a PC but the target system often has a different processor.
The PC uses an Intel processor, the Raspberry Pi an ARM (different instruction set)
The Raspberry Pi is powerful enough for native compilation (gcc compiler on Raspberry Pi)
There is a cross compiler for ARM machines on Linux (arm-linux-gcc)
We can compile programs on the PC and transfer and executed them on the ARM processor
Linux has an ARM emulator on which many ARM programs can be executed (including an ARM Linux OS!)