Differences

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--- rtes:topics:arduino:start [2017/10/17 10:56] – [4. Analog Output] admin
+++ rtes:topics:arduino:start [2018/10/18 08:56] (current) – [Lecture Notes] admin
@@ Line 1: / Line 1: @@
 ====== Intro to Arduino ======
-|  {{https://store-cdn.arduino.cc/uni/catalog/product/cache/1/image/520x330/604a3538c15e081937dbfbd20aa60aad/a/0/a000111_featured.jpg?600}}  |
+|  {{https://store-cdn.arduino.cc/uni/catalog/product/cache/1/image/520x330/604a3538c15e081937dbfbd20aa60aad/a/0/a000066_featured_1_.jpg?600}}  |
-|  //Fig.: Arduino M0 Pro. CPU: ATSAMD21G18, 32-bit ARM Cortex M0+ //  |
+|  //Fig.: Arduino UNO Rev 3. CPU: Microchip (Atmel) ATmega328p, 8-bit AVR Core. https://store.arduino.cc/arduino-uno-rev3 //  |
 /*
@@ Line 14: / Line 14: @@
 */
-**Technical data (Arduino M0 Pro processor)**
+**Technical data (Arduino UNO processor)**
-  * Microcontroller: ATSAMD21G18, 32-bit ARM Cortex M0+
+  * Microcontroller	ATmega328P
-  * Embedded debugger
+  * Operating Voltage	5V
-  * Operating voltage: 3.3 V
+  * Input Voltage (recommended)	7-12V
-  * Input voltage: 7 - 12 V
+  * Input Voltage (limit)	6-20V
-  * Input voltage, max.: 6 - 20 V
+  * Digital I/O Pins	14 (of which 6 provide PWM output)
-  * Digital I/O pins: 20 (2 PWM)
+  * PWM Digital I/O Pins	6
-  * UART: 1
+  * Analog Input Pins	6
-  * Analogue input pins: 6, 12-bit ADC channel
+  * DC Current per I/O Pin	20 mA
-  * Analogue output pins: 1, 10-bit DAC
+  * DC Current for 3.3V Pin	50 mA
-  * DC per I/O pin: 7 mA
+  * Flash Memory	32 KB (ATmega328P) of which 0.5 KB used by bootloader
-  * Flash memory: 256 KB
+  * SRAM	2 KB (ATmega328P)
-  * SRAM: 32 KB
+  * EEPROM	1 KB (ATmega328P)
-  * 32-bit real-time counter (RTC) with clock/calendar function
+  * Clock Speed	16 MHz
-  * 32-bit CRC generator
+  * https://store.arduino.cc/arduino-uno-rev3
-  * Two-channel Inter IC Sound (I2S) interface
-  * Peripheral touch controller (PTC)
-  * Clock speed: 48 MHz
-https://store.arduino.cc/arduino-m0-pro
 ===== Lecture Notes =====
+==== University of Washington, Computer Sciences (CS), Course Number CSE P567 ====
+  * [[https://courses.cs.washington.edu/courses/csep567/10wi/lectures/Lecture6.pdf|Lecture 6 – Introduction to the ATmega328 and Arduino]]
+  * [[https://courses.cs.washington.edu/courses/csep567/10wi/lectures/Lecture7.pdf|Lecture 7 – ATmega328 Timers
+and Interrupts]]
 /*
@@ Line 61: / Line 62: @@
 ===== Lab / Exercises =====
-==== Background: ARM Cortex M0+ Processor ====
+==== Background: Atmega328P Processor ====
-{{https://www.arduino.cc/en/uploads/Guide/M0Pro_Usb_Ports.jpg?400}}
+The CPU used is [[https://www.microchip.com/wwwproducts/en/ATmega328p|ATmega328p]] having been designed by the former company Atmel which has been taken over by Microchip.
-We will use the next generation **[[https://store.arduino.cc/arduino-m0-pro|Arduino M0 Pro]]** for this course. Its core is an **[[https://en.wikipedia.org/wiki/ARM_Cortex-M|ARM Cortex M0+]]** processor which make it faster and more powerful than the Arduino UNO based on the AVR-8-bit core.
-The CPU used is [[http://www.microchip.com/wwwproducts/en/ATsamd21g18|ATSAMD21G18]] having been designed by the former company Atmel which now has been taken over by Microchip.
@@ Line 79: / Line 76: @@
 ==== Setting up the Arduino IDE tool chain ====
-Please follow the instructions on [[https://www.arduino.cc/en/Guide/ArduinoM0|Getting started with the Arduino M0 Pro]].
+Please follow the instructions on [[https://www.arduino.cc/en/Guide/ArduinoUno|Getting started with the Arduino and Genuino UNO]].
 ==== 0. General Basic Commands ====
@@ Line 123: / Line 120: @@
-  * How to connect switches to ditital inputs: Why do we have to use pull-up or pull-down resistors?
+  * How to connect switches to digital inputs: Why do we have to use pull-up or pull-down resistors?
   * How to use and activate internal pull-up resistors of ATmega328 GPIO pins
   * //If buttonPressed() then ... else ... endif//
@@ Line 142: / Line 139: @@
-==== 4. Analog Output ====
+==== 4. Analog Output by Pulse Width Modulation ====
+The "old" AVR microcontrollers such as ATmege328, the core of Arduino UNO, do not have a real analog output. To work around this limitation a method called Pulse Width Modulation (PWM) is used. A square wave signal of fixed frequency is generated and provided at a port pin (digital output). The pulse width of the square wave (the time for the signal being logic high) can be changed whereas the total signal period T is kept constant (as a result of constant frequency).
+The ratio $r = \mathrm{\frac{pulse\;width}{period}}$ is called duty cycle.
+The average voltage of the signal is then a linear function of $r$:
-The "old" AVR microcontrollers such as ATmege328 (used with Arduino UNO) do not have a real analog output. To work around this limitation a method called Pulse Width Modulation (PWM) is used. A square wave signal of fixed frequency is generated and provided at a port pin (digital output). The pulse width of the square wave (the time for the signal being logic high) can be changed whereas the total signal period T is kept constant (as a result of constant frequency).
+$V_\mathrm{avg} = r\cdot V_\mathrm{cc} + (1-r)\cdot 0V = r\cdot V_\mathrm{cc}$
-The ratio $r = \rmmath{\frac{pulse width}{period}}$ is called duty cycle.
-  * Use the function "analog_out()".
+  * Use the function "analog_out()". Observe the output signal with the oscilloscope.
   * Resolution of PWM? How many bits? How many different amplitude values?
-  * Read values from a potentiometer (10 bit), map the values to an 8 bit range and use the scaled value for a PWM output. Dim a LED.
+  * Read values from a potentiometer (10 bit), map the values to an 8 bit range \\ and use the scaled value for a PWM output. Dim a LED.
 ==== 5. Serial Communication (UART) ====