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Trying to build a cheap and simple oscilloscope. How to program an AVR?

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LAN_403

cavemen

Sun Aug 30 2009, 09:50PM

Registered Member #2008 Joined: Tue Mar 03 2009, 05:11AM
Location: USA, Frederick, MD
Posts: 118

I want to build this scope.

How would i have to program the Atmel Tiny45-20?
Do I need a special jig for hooking this chip up to my PC?

What code do I put in out of all the files?

I never programmed microcontrollers before.

Thanks.

does this apply?
how do i hook it up?

[edit: Double post]

3l3ctrici7y

Mon Aug 31 2009, 01:31AM

Registered Member #1806 Joined: Sun Nov 09 2008, 04:58AM
Location: USA
Posts: 136

On the instructables page it shows a connection diagram where you connect the wires from the computer to the wires on the microcontroller.

You will want to grab the datasheet for the attiny45 and find where the relevant pins are; you will want VCC, VSS, /RESET, SCK, MOSI, and MISO. You can follow the instructions in the instructable; it will say which parallel port pin to connect to what named pin on the microcontroller.

You will have to setup the development environment on your computer so that you can run AVRDUDE to do the actual programming. Something else is that with parallel port programmers; you cannot use a cable. You must plug it directly into the computer. Also; it would be best if you directly powered the chip with a regulated 5 volt supply rather than rely on the computer to power the chip.

What I did is mount a DIP socket on a small piece of perfboard along with a DB25 connector to connect to the computer's parallel port, and a power jack for connecting the regulated supply.

5v power supplies are quite common.. if you have a computer power supply sitting around, you can use that. Zip drives use 5v power, some cell phone chargers are, and if all else fails, you can get a combo 5/12 volt supply off of a HongKong seller on ebay for a very small sum of money.

To directly answer your questions...
1) Build or buy a programmer; the instructable page described building one.
2) Yes.
3) You download the files from the page describing the oscope; that should have the necessary stuff.
4) Yes.
5) The instructable describes that.

[Edit: Double post]

cavemen

Mon Aug 31 2009, 02:13AM

Registered Member #2008 Joined: Tue Mar 03 2009, 05:11AM
Location: USA, Frederick, MD
Posts: 118

Thanks.

Or should I build this scope:

I am in doubt, but same techniques apply.

3l3ctrici7y

Mon Aug 31 2009, 03:37AM

Registered Member #1806 Joined: Sun Nov 09 2008, 04:58AM
Location: USA
Posts: 136

Personally I prefer the AVR over the PIC.
Therefore I suggest building the AVR version (the first one you mentioned.

Wolfram

Mon Aug 31 2009, 04:48PM

Registered Member #33 Joined: Sat Feb 04 2006, 01:31PM
Location: Norway
Posts: 971

Which one to chose depends on how fast signals you are going to measure, also. The AVR one can do some hundreds of samples per second, the PIC one does 60 000.

Anders M.

cavemen

Mon Aug 31 2009, 09:27PM

Registered Member #2008 Joined: Tue Mar 03 2009, 05:11AM
Location: USA, Frederick, MD
Posts: 118

I like PIC circuit more, because i need high frequincy oscilloscope.

The only problem is that there is a ghetto way to program AVR using computer parallel port described on Instructables.com, but i couldn't find any simple jug like that for programming PICs.

Is there such simple solution for PIC?
Can you give me the link, please, if you know something.

and the official microchip website are the only resources I found.

I never messed with microcontrollers before, so i don't know how to do this stuff by just reading the data sheet.

Also i don't want to build a complex device.

[Moderator Edit: Fixed double post.]

Wolfram

Tue Sept 01 2009, 09:26AM

Registered Member #33 Joined: Sat Feb 04 2006, 01:31PM
Location: Norway
Posts: 971

The Tiny PIC Bootloader won't help you in this case, as you need to program it into the PIC before you can use it.

There are many simple serial port PIC programmers, here's an example:

For the programming software to use, I can recommend

Also, please don't double post.

Anders M.

cavemen

Wed Sept 02 2009, 01:16AM

Registered Member #2008 Joined: Tue Mar 03 2009, 05:11AM
Location: USA, Frederick, MD
Posts: 118

Can this circuit do the programming?

I really like the idea of using my paralel port. for programming.

No data buffering, simple as hell.

Then i just add the code into the program and it programs it for me?

...

Wed Sept 02 2009, 05:03AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

Another solution would be to have someone with a programmer do it, there are several members on the forum with them. i would offer, but I am in hawaii right now and would not be able to get to it for a week or so.

cavemen

Sat Sept 05 2009, 04:06PM

Registered Member #2008 Joined: Tue Mar 03 2009, 05:11AM
Location: USA, Frederick, MD
Posts: 118

As i noticed, the oscilloscope

should be built with a mysterious circuit that is titled RS-232 level converter.

The author says it is for computer to communicate with the circuit by standard 5V signals.

Is it device a programmer that uses serial port to program this microcontroller while it is already soldered into the circuit board?

Is this device a programmer?

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