Lecture 5

Uli Raich

UCC semester 2017/2018

A first glimpse

There are several versions of Raspberry Pis available on the market:

• Raspberry Pi 1 Model B released in 2012
• There is also a simpler and cheaper model A
• Raspberry 2 with more memory
• Raspberry Pi zero a stripped down version for 5 US$
• Raspberry Pi zero W same as zero but with WiFi and Bluetooth for 10 US$
• Raspberry Pi 3 fully equipped model that we will be using

Raspberry Pi specs

Operating systems on the Pi

From the specs we can see that the Raspberry Pi 3 is a full blown computer.

With its

• 64 bit quad core processor
• 1 Gbyte of RAM
• 32 Gbyte of SD card

a full particle accelerator and it is also much more powerful

than the computer system that allowed the moon landing!

This allows a great deal of flexibility when it comes to

operating systems to be installed on the machine

Currently available OS

• Raspbian, a Debian variant of Linux tailored to the Raspberry Pi.
  
  
• It contains most of the software packages you also find on Ubuntu
  
  The Desktop is however stripped down to make it more
  
  responsive on a processor that cannot cope with the speed of a PC
  
  This is what we are using!
  
  
• Ubuntu Mate is a Ubuntu variant for the Pi
  
  
• Windows 10 IOT core, a windows variant. I have never tried this but
  
  Windows gurus may give it a try if they cannot live without Windows on the Pi
  
  
• Android: There are several Android versions for the Pi floating
  
  around on the WEB. Your success on these may vary
  
  
• Kodi is a multimedia server that will allow you to listen to music,
  
  look at photos or watch films. Connect your Pi to a TV set
  
  (through the HDMI connector) and a stereo and off you go!

BCM2835 CPU

The CPU has got an ARM processor core with 4 64 bit CPUs

The operating system and the Linux kernel are still 32 bit versions

(After the course you may try to compile and install

a 64 bit kernel yourself. This is a very good exercise to

understand how the OS is built!)

Around the CPU there are plenty of interfaces

To know the details (the interfaces only!) have a look at the data sheet explaining them (205 pages!)

BCM2835 peripherals

Here are some of the Raspberry Pi peripherals:

• UART
• SPI
• BSC (serial controller)
• DMA controller
• External mass media controller
• PCM / I2S Audio
• Pulse Width Modulation
• Timer
• USB
• I2C
• GPIO

Raspberry Pi and the real world

You can easily connect

• General Purpose Input Output signals
  
  
• These are 3.3 V single pin signals used e.g. to drive a LED,
  
  a relay or any other device needing a digital signal level
  
  
• You can program it input or output
  
  
  • With pull-ups or pull-downs
    
    
  • To read switch state
    
    
  • To drive a 3.3V output level (and light a LED)

Connection to bread board: The cobbler

Other Rpi connections

I2C is a serial bus often used in computer systems of for

short distance interfacing. Many devices having a I2C port

are available and we will program a few:

• ADC
  
  
• DAC
  
  
• Real time clock
  
  
• EEPROM
  
  
• We also have a 2-line LCD display needing some 8 signals
  
  (+ power and gnd). A serial to parallel interface (shift register)
  
  with I2C interface eases the connection to the Raspberry Pi
  
  as only 4 serial signal lines are needed: SDA, SCL,Vcc, gnd

Slide 1: The Raspberry Pi and how to bring it to life

-- Uli Raich - 2017-09-13

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