Hammers

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Mich the Tester replied

9 September 2011, 13:26
Originally posted by doodab View Post

Someone is hammering. I am trying to read a 300 page MCU datasheet. These activities are incompatible on a fundamental level.

Sorry, that was me banging our Bob's head against a wall.
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doodab replied

9 September 2011, 13:21
Originally posted by zeitghost

Crystal osc or RC?

What PCB software?

<ZG in "I'm a nosey lizard" mode>

PCB software = the free version of eagle. I've only ever used stripboard so it's a bit of a learning curve.

The oscillator is an op amp based relaxation oscillator for audio frequency square & sawtooth waves, the plan is to build an audio frequency signal generator with sweep. For some reason the period seems to be about half what it should be and vary with supply rail voltage which also isn't supposed to happen. I suspected perhaps a short across one of the resistors somewhere but it all measures out OK, even changing some components and recalculating didn't help, I got the same sort of error. My next guess was slew limiting on the op amp output but I don't think that should be an issue at < 1KHz. I tried another design from one of those babani books and that didn't even oscillate, no idea what was wrong with that so I went back to plan A.

The wein bridge sine wave one works pretty well though, I just need to figure out how to make the frequency voltage controlled now

Can you tell I have little or no clue what I'm doing? At least with the analogue stuff it's all a bit of a mystery at the moment.
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doodab replied

9 September 2011, 11:51
Originally posted by zeitghost

Enjoy.

Don't forget to read the silicon errata as well.

I won't need that for a while, I'm still at the "why does my oscillator simulate OK but have a totally different period when I build it" stage. Unless my breadboard has parasitic capacitance in the 100s of nF I'm buggered if I know what's wrong with it.

I suspect the PCB design software I've downloaded is going to have a bit of a learning curve as well.
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doodab replied

9 September 2011, 10:27
Atmel ATMega32A. It's research for plan Q.
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chef replied

9 September 2011, 10:10
Originally posted by doodab View Post

Someone is hammering. I am trying to read a 300 page MCU datasheet. These activities are incompatible on a fundamental level.

what's the datasheet? work related or the latest tinkering project?
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Arturo Bassick replied

9 September 2011, 10:01
Billy Bonds, Trevor Brooking, Bobby Moore.
Jumpers for goal posts.
Those were the days, what?
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SimonMac replied

9 September 2011, 09:59
Ah if I had a hammer.....
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doodab started a topic Hammers

9 September 2011, 09:56
Hammers

Someone is hammering. I am trying to read a 300 page MCU datasheet. These activities are incompatible on a fundamental level.
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