See the crystals and how they're hooked up?

ahhh, well out of curiosity, i went and just re-tried what i tried a few weeks back

I was wrong..


You CAN upload via ISP of an Arduino and flash the bootload and upload binaries, with nothing more than just a 20mhz crystal, no caps.
You CAN'T however run a sketch and have it run with just the 20mhz crystal, eg let's say pin 0 on/1000ms/0 off , what will happen is pin 0 will trigger high or low and not turn off, no idea what's going on here.

Interesting, to simply flash a new bootloader or upload a sketch, the Cap's don't appear to be needed!

Take any Atmel chip which relies on a 2 pin crystal oscillator.

You attach the 27pf caps, wire it all up correctly, upload and have it blink 1second of / 1 second off.

We now remove the 2 ceramic caps. (i've tried this)

In my test.

2 Attiny85s

1 Attiny, used the Caps and a 2 pin 20mhz crystal
2nd Attiny, used just the 20mhz crystal

The only visible difference was the LED's were starting to shift out of phase, maybe 1 - 2ms gain/loss every second..


But what i found interesting is the chip kept on working without the Caps.... I wish i tried to upload without the caps and just relying on the crystal now, so why
are the 2 ceramic low value cap's so vital in the role of time keeping?

My first post vanished.

Look at the Crystal, see how your GND connection is not even connected, it's 1 pin to the left!..

move the GND wire so it's in series with the crystal (ie, 1 pin to the right of where it is now), your chip should spring to life

my bad - i saw "shrinkify" only a few hours earlier did i come across "how to shrinkify your arduino" via a youtube vid, i presumed you were using an Attiny, my bad.

well, there's plenty of options, shift registers are the best way to go if all you're doing is reading a bunch of high/low signals.

Waymon - Look at your breadboard, see the 2 ceramic caps and your crystal, GND is not connected!

only 1 side of the crystal is connected to GND via the caps, the other is not..  - fix that and it should upload fine.

RFI is my Arch Nemesis!

Over the years (with exception to my desktop PSU) I've had horrible dealings with RFI, light switches, ovens anything that arcs.

So i've been converting all things electronic that run on DC to run from DC, eg, the Modem 11dc from an AC switching adapter, well that AC was causing a small unwanted amount of noise, So i hooked it up to a 12v small lead acid battery (there's a DC > DC regulator inside the modem rated for 22volts) so now i get a cleaner Data Transfer signal, Tesla was a genius but he never stopped ONCE to think about people who work with microcontrollers and IC's lol..

There's a sound / clap sensor circuit I made years ago, everytime you clapped the mic picked up the sound using a flip flop, triggered a relay, but the relay caused a spark causing the circuit to turn off again! what a badly designed circuit! - I had to run it off a 9v battery to make it work properly.

a picture would be helpful, try swapping the sda scl lines around, sounds like a connection issue

Besides, I could use a row of male/female header pins on the output/inputs of the chip you're programming or even a few LED's with 300 ohm resistors in series to prevent it interfering when flashing over SPI.

The problem with that approach is that every time you want to modify the program in your home-made board, you need to remove the microcontroller and put it in the programmer. Then move it back again before you can test the new program. You'll probably find that the program isn't quite right, so you modify the program and repeat the process a number of times. And you can't use SMD microcontrollers this way.

It's more practical to put an ICSP header on the board and program/reprogram the chip in-situ.

That's how I program the ATTiny's i currently have? (lift them in and out when done, that's the point of a programmer?)... How do you go about it?

The Perfect programmer would have to be an Atmega328p (or if it's possible to fit the ISP sketch and change the pin configuration... an Attiny85) on a PCB board.

Ideally the perfect flavor would consist of a a ZIF Socket for the chip to be programmed either an Attiny series or an Atmega328p, mounted on the board would  have to be a 5v regulator, a USB input and a Mega8u2 and obviously the pre programmed with the ISP sketch on either an Attiny (if possible to keep costs down) or an Atmega328p.

(The user using it)
End Result - You place the chip to be programmed into the ZIFF socket, you plug in your USB cable, go to Arduino, select your chip to be programmed (eg attiny85) select Arduino as ISP, now upload your blink sketch and use pins accordingly.

you'd be able to carry it around with you and a couple of chips, and program anytime anywhere! - please tell me this has been done

Before you say google it... that's not what i'm thinking.

What if i did something like, output on pin 2 or 3 turn it off, and wait... would i get a voltage back from the voltage i sent it to? or an inverse voltage? is it even possible? is it possible to have any fun with crystals and arduino?

Long story short.

I burnt a 20mhz bootloader onto my attiny85, it worked, but then it stopped working completely, so I placed
a 20mhz crystal as explained and the smallest ceramic caps i could find!

Still dead, So I went out to jaycar, picked up 2 27p ceramic caps, placed them in series with the outputs of the crystal and into the 2 pins, viola it all works!

Great, but my damn annoying inquisitive side of me nature springs alive!!!...  So i've been sitting here for 20 minutes wondering how it works!

A voltage is passed to the crystal and turned off, the crystal then UN-distorts back to it's original shape sending out a pulse, how does that affect the capacitor and the roles they play back to the Arduino Pins that have the xtal across them?

what precisely is going on here, I took my multimeter and switched to hertz, placed one probe on one of the crystal pins, and then the other to ground and I got the arduino doing ever increasingly slower osccilations until it hit around 2 - 1 hz and it crashed - reboot later the might attiny85 was back!

i'm trying to imagine how the electrons pass both in and out, anyone know a windows circuit emulator which shows the current / voltage path of the electrons like AllCircuits i think it's called for Android? but in Windows? - there's no crystal to select from sadly, i need a more complex designer...

Thanks... (in other words, how does the crystal do it's job and what are the role of the caps, i've googled it, it just made it worse)

yup, I'm merely trying to get my head around how it works... making them is simple, but how they work..

but this -5volt swing has got me curious, i need an oscilloscope - thanks all, tomorrow i'll probe this circuit with my multimeter and give this relaxation oscillator / multivibrator /  flip flop /astable osccilator / a good going over lol, i'll increase resistor and cap sizes and try and watch the voltages across the caps and bases of the transistor to see this in action, i built it, it worked i just have to slow it down..

p.s

if i see a yellow canary, it's a canary, if i see an orange canary, i don't start suddenly start calling the canary (even though it's a different colour) something else! (electronic engineers seem to do, 1 name is never enough)

Don't tell me magic

I was told in the Air Force when we studied this circuit that it indeed was magic.  

 That is if your question really is: upon initial power up for this circuit which transistor will switch on first, Q1 or Q2? And will that always be the case upon each powering up event? Lets let the peanut gallery chew on that one for awhile.

Possible answers:

A:   Q1 always.
B:   Q2 always.
C:   It's always random if either Q1 or Q2 starts first.
D:   It can be either Q1 or Q2 but it will be the same transistor starting first for each specific circuit built.
E:   Some other magic will decide which transistor starts first.
 

I prefer the first answer given to you were in the air force - magic