1. Chapter A - The Raspberry Pi Computer
Credit Card-size computer introduced in 2012
LINUX operating system
Large number of reconfigurable General Purpose Input/Output digital pins (GPIO)
Communication via SPI, I2C, and UART interfaces
Two hardware Pulse-Width Modulation PWM channels
No analog inputs-- we use an MCP3008, an 8-channel, 10 bit A/D converter for analog data

2. Specifications https://www. raspberrypi
SoC: Broadcom BCM2837 CPU: 4× ARM Cortex-A53, 1.2GHz GPU: Broadcom VideoCore IV RAM: 1GB LPDDR2 (900 MHz) Networking: 10/100 Ethernet, 2.4GHz n wireless Bluetooth: Bluetooth 4.1 Classic, Bluetooth Low Energy Storage: microSD GPIO: 40-pin header, populated Ports: HDMI, 3.5mm analogue audio-video jack, 4× USB 2.0, Ethernet, Camera Serial Interface (CSI), Display Serial Interface (DSI)

3. The Raspberrry Pi

4. Another Rpi view

5. GPIO Pinout for the RPi 3

6. GPIO Pinout for the RPi 3 Several communication protocols available:
40 unbuffered pins
An incorrect connection may destroy RPi
Two 5V & two 3.3V.
High current applications require external source
Eight Grounds
13 digital I/O pins
Several communication protocols available:
One I2C
Two SPI
One UART
Two PWM

7. Accessing the GPIO Requires a special library
Will be included on your SD card
Requires a directive for your code:
#include <bcm2835.h>
Requires a change to the build command:
gcc program.c -o program -lbcm2835
Requires a change to your execution:
sudo program
(“sudo” stands for “super user do” )

8. Sample code – the blink.c program
// Example program for bcm2835 library
// Blinks a pin on an off every 0.5 secs
// Author: Mike McCauley Copyright (C) 2011 Mike McCauley //
#include <bcm2835.h>
// Blinks on RPi Plug P1 pin 13(which is GPIO pin 27)
#define PIN RPI_BPLUS_GPIO_J8_13
int main(int argc, char **argv) {
if (!bcm2835_init()) return 1; //start using GPIO; indicate if error
// Set the pin to be an output
bcm2835_gpio_fsel(PIN, BCM2835_GPIO_FSEL_OUTP);

9. The blink.c program continued
// Blink forever while (1) { bcm2835_gpio_write(PIN, HIGH); // Turn pin/LED on bcm2835_delay(500); // wait ½ second bcm2835_gpio_write(PIN, LOW); // turn pin/LED off } bcm2835_close(); // signals end to use of GPIO return 0;

10. Changes to compilation and execution
First, library must be installed (this is already on your SD cards!)
For build (need to link library):
gcc -o blink blink.c -l bcm2835
For execute (need more authority to access GPIO):
sudo ./blink
(sudo - execute a command as another user)

11. Testing the code

12. Analyzing the circuit

13. Common errors Connecting to any other pin
Putting the diode in backwards
No harm done – simply doesn’t light up
Forgetting the resistor
Very bright diode, then diode death
Connecting to wrong GPIO pin or
Connecting to 5V instead of ground
Connecting to any other pin
????

14. Laboratory Assignment #2
This lab lasts two weeks!!!
Generate and run the program “blink.”
Generate and run a program that allows you to type in an integer k (0 to quit) and then have the led blink k times.
Generate and run a program that allows you to type in a sentence and then have the led blink that word in Morse code (no input loop).

15. International Morse Code table