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.

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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