Friday, November 28, 2008

AVR electronics and the wonders of the Soldering Iron

After phaffing about for a few weeks I have finally managed to write a blog entry.

Now I started with the PIC micros , but found the whole AVR thing made more sense to me. I was already running linux so gcc seemed the way to go.

So.... If you live Australia the local Electronics store is a probably a Jaycar.

They have two kits to get you started.

1. the ISP Programmer
2. the Adaptor Board

Put these together as per instruction and you can program AVRs with ease over a serial port using avrdude.

From Reprap Electronics

From Reprap Electronics

I Purchased ZIF sockets for the 28 and 40 Pin sockets, they are $++ however they save a lifetime of pain in the long term. You may have also noticed that I soldered in the 20 Pin socket as well. There is a good reason for this.

The firmware that comes with the jaycar kit is really old and would not even detect the atmega64 at all. So I purchased another of the micros in the programmer and used the programmer to upload it to the new chip.

The avr910 firmware is available from sourceforge. I'm using 3.2.3 as it worked.

Once you have uploaded it change out the mirco on the ISP programmer to the new one and test it. Then I copied the original program of the old micro and loaded the new firmware onto it. This then went into my parts draw on anti-static rubber and a label on it.

When you are using Avrdude

avrdude -c avr910 -p m8 -t -P /dev/ttyS1

Right.... programmer updated.

I then went to work on putting together some control boards.

From Reprap Electronics

This is an atmega8 controller , connected via twi + GND + 5V there is also a atmega644 version called boris.

On another note you can make an easy ISP cable that has minimal set up on vero board, just a 6 pin header. On the atmega8 you just need to run the reset around to pin 1 and on the atmega644 you can just solder it straight in.

I made a cable for the avr910 ( from Jaycar ) that looks like this

The left hand plug goes to the vero board the right hand plug is in the ISP programmer.

From Reprap Electronics

Vlad is the same basic board with a l293d wired it , this is a dual H-bridge that can take 0.6 A per channel and is pin compatible with other hight current drivers.

From Reprap Electronics

At present I am hacking up the two wire bootloader from the openservo project and hope to have it running stepper motors soon.

So reprap in motion , Electronics %40 and rising , the guy with the laser cutter gets back from up North in a few weeks. I estimate that I'll be printing in about 2-3 months ( time and spendoolies permitting).

1 comment:

khiraly said...

Arduino can not be used as an avr programmer?