make your own developement board @ 2014.4.21 juluosdev

Make Your Own Development Board

ATMega8 series for example

StarNight @ 2014.4.21 JuluOSDev

After sharing Simple Scheduler @ OSDC.tw 2014,

it is a good chance to talk about the hardware implementation of

Simple Osilloscope

1. (Highest Order)Meet the specification.

2. Smallest cost.

3. Finish it in shortest time.

by

Boundary Conditions!!!

Lessons Learned from PMP (Partial)

Initiating Develop project charter

Planning Collect requirements Define scope Plan Quality Estimate costs Develop schedule

Excuting Monitoring & controlling Closing

The specification going to be met.

Find the smallest cost.Find the shortest time.

The Specification of osilloscope

Signal range: 0 ~ 5V

Sampling frequency: 100 Hz

Sampling channels: 6 ~ 8 channels

Connects to computer with UART

Communication protocal: Modbus

Students homework is a practice which finds the f(x) from x. However, engineers work is

a problem which finds the x from f(x).

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The Cost and Time

I can use: The ADC channels of AVR. The timer of AVR for periodic sampling. The USART function of AVR.

I can buy an AVR with the money that I can afford.

I am familiar with AVR, which shorts development time.

There are open source resource for AVR, ex: toolchain, programmer ...

Read Datasheet

Reference from: ATmega328 datasheet

Build a development board

That will be an oscilloscope.https://github.com/starnight/ATmega328-Board

Tools

Toolchain:avr-gcc

Libc:avr-libc

Downloader/Uploader:avrdude

Prgrammer:USBtinyISP, USBasp ...

I flashedSimple Oscilloscope

firmware into the development board.

https://github.com/starnight/Simple-Oscilloscope

Function Generator for SignalsSchmitt Trigger Integrator

Could reference: http://www.pcbheaven.com/circuitpages/Triangle_Wave_Generator/

Function Generator

Oscilloscope Console by python + pyserial + matplotlib

All Circuits Analysis Begins with

On - Off

For a resistor:v(t) = i(t) r(t)

For a capacitor:q(t) = C(t) v(t)

For an inductor:v(t) = d ( L(t) i(t) ) / dt

Lessons Learned from Oscilloscope

Nyquist Frequency / Aliasing

http://en.wikipedia.org/wiki/Aliasing

We need to integrate the knowledge learned from school and use it when implementation.

Build your own tools ~

Thats maker !!!!!

Thank you and Q & A

https://github.com/starnight/ATmega328-Board