help with interfacing microcontroller to pga volume chip

[Lingwendil]

Hello, I'm building a volume control using the PGA2311 IC and the PIC16F684 microcontroller. My project goals are to allow volume up/down, mute, and amplifier power off (via a relay), and it needs to receive its signal from both pushbuttons and a universal remote control (xbox360 remote). I know nothing of the programming involved but can easily take care of the hardware. Anyone know of such a setup that has code available? If not, some links to learning what I need to do this would be a great help.

[Alien8]

Hi

I'd strongly suggest you invest some time in learning some form of programming language !
Although the opinions may differ I'd tentatively recommend jal.

A few years ago there was a similar project in Elektor (the audiolink).
The source is available and quite easy to adapt to your hardware.

Feel free to ask further assistance

It's good to invest some time in learning how to do it. It was certainly a good thing to learn about programming stuff. Just have fun.

HTH Alien8

[Lingwendil]

Well, I found this link: TheNewBoston – Free Educational Video Tutorials on Computer Programming and More! C Would that be a good place to start? Also, the part that I'm having the most difficuty with is that I'm not quite sure I grasp the description on the PGA2311 datasheet as to the implementation of the control data.

[Lingwendil]

Oh, and I also have a couple PIC12F68 that I could use if they would work here.

[suzyj]

Here's how I did it:

A HiFi Preamp

[Lingwendil]

Will your code work on a PIC16F684? Also, did you ever get it to decode the input from a remote control? I don't need a rotary encoder for this design.

[Alien8]

Hi Lingwendil

My suggestion was a so called higher level programming language...
There are a lot of different choices here. Basically it turns out to be a lot easier if you pick a high level language. Here the compiler (the program that actually writes the machine code and spits out a hex file) takes care of the more difficult parts for you. The disadvantage is that time critical software may not work correct... On the other hand a lower level language expects the progammer to know a lot more of how to make a microcontroller work, but you are more in control of things.
As you've probabely guessed a low level language has a very steep learning curve........

My suggestion was to use JAL - Just Another Language (google it) which is very easy to start with. As said above, Elektor has a project published based on this language.

As to control the PGA chips : basically you need to 'select' it by pulling the cs line low (the bar above it in the datasheet means 'active' when low) and send two bytes - one for left, one for right by putting a bit on the data line and toggling the clock line. The PGA reads in a bit at each low to high transition of the clock line.
This is a common way to address and transfer data from chip to chip.
You could eg. use the data and clock lines connected to different chips and 'select' the right one to talk to using the cs line. Just leave it high for the ones you don't want to 'listen' ... Once you start you'll find yourself needing more and more pins on your microcontroller. The chip makers solved part of your problem here !
Examples are found easily on the web. The legendary preamp from mhennessy uses some of these tricks.

Good luck!

[Lingwendil]

Also, the xbox 360 remote uses rc6 protocol, and all i've been able to find is rc5, anyone know of any sites discussing rc6 in detail?

[gfiandy]

I am not sure this is still true but when I was still working on this RC5 was developed by Philips and they released it for use unlicenced. It was very popular so they developed a new improved version RC6 which they licence to manufacturers.

Hence you may find it difficult to find data on RC6 on the web.

Regards,
Andrew

[Alien8]

For RC6 check : rc6 encoding

Are you sure all the commands on your remote are RC6 ? There is also an extended (more than 64 commands) RC5 available. Sometimes that is used and mistakenly advertised as RC6.

I once started on a decoding algorithm for RC6 but since I have a programmable remote I have no more need for that.

A8