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Old 15th September 2005, 02:17 AM   #11
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1) all micro-controllers like to generate clock noise
2) the microcontroller control lines should be decoupled with a resistor.
3) the microcontroller should be turned 90 degrees counter-clockwise -- makes the layout a bit more rational.
4) if you are using decoupling caps, and mixing SMT with through-hole -- use SMT decoupling caps.
5) use a separate digital ground and analog ground

You will get there -- your enthusiasm demonstrates it.
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Old 15th September 2005, 01:41 PM   #12
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Default Blazing a trail

Russ,
Have you seen the preamp thread in the chip amp forum or my posts on Headwize? May give you ideas as those designs from a microcontroller and digital volume control perspective, are the same.
Cheers -ALBQ

My PGA2310 design - thread on Headwize
http://mywebpages.comcast.net/gilles...A2310-REV2.jpg
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Old 18th September 2005, 02:21 PM   #13
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Default Need some coding help.. Please!!! :)

I will have to devide this into a couple of posts to get the images in.

I have implemented the following PCB...
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Old 18th September 2005, 02:24 PM   #14
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And stuffed it....
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Old 18th September 2005, 02:26 PM   #15
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It is based on this schematic..
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Old 18th September 2005, 02:28 PM   #16
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Ok, now where I need help. The controller is the PIC12F83 (which is what I have on hand) which has the necessary ADC. I just can't figure out how to write the code to send the serial data to the PGA2311.

Can someone please help me with the code?

This is my first PIC project and I am a total MCU n00ber.

I have the PICC Lite compiler and MPLAB, which is what I would prefer to use, but ASM code for MPASM is fine too.

Please help me figure this out.

Cheers!
Russ
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Old 18th September 2005, 03:45 PM   #17
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I bet it's a PIC12F683 that you have on hand.

Microchip has resources (assembler etc.) which you can download from their site for programming this device -- but first you have to flowchart what you want the device to do. They also have code which you can cut and paste.

Frankly, I find that it is easier to use MELABs PicBasic Pro -- on their website www.melabs.com you can view the manual.

there is plenty of discussion to help you get started at http://www.picbasic.co.uk/forum/
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Old 18th September 2005, 04:04 PM   #18
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Yes, my mistake, its a PIC12F683. Thanks.

Well the program flow is pretty simple.

I am not a programming noob, just a PIC noob.

So, I don't mind using C or ASM, its just finding a clear example has been a challenge so far.

Thanks for your pointers.
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Old 18th September 2005, 04:19 PM   #19
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Default Development approach

The program would be simple

1) Read 8bit from ADC to correspond to the voltage divider of the pot.

2) Apply the value to the volume control on both channels.

Here is some lame pseudo code

main() {
while(true) // loop forever
{
int potValue = readADC(potPin);
setVolume(potValue);
wait(100);// wait 100ms
}
}
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Old 18th September 2005, 07:57 PM   #20
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Hi Russ,

If you could post here the bus speed of the PGA2311; mebbe i can have a look see...

~M.
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