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metal 24th May 2005 07:41 PM

Digitally Controlled Volume, Tone IC ??
Hello every one

Its been long time ago since I have participated in a thread, nor posted new one...

I spent the last few months learning PIC microcontroller programming, built my own programmer, and have stolen lots of software to accomplish the dream of PIC MCUs programming.

When I first participated in this forum, I always wanted to control audio digitally, so I kept looking for those ICs that support conact switches instead of MCUs control, such as DS1960 as I remember.

Now I can make any thing I want with PICs, starting from LED blinking, to serial communication, and I am really happy with this, my last project was using PGA2310 to control volume, very nice LCD was included too, to display volume reading in decibles, and to show mute state, if switched on or off.

I thought I could use TDA1524 volume and tone control with digitally controlled potentiometers, such PGA2310, but this is still a tedious work.

I mean if I want to control TDA1524 using digi potentiometers, I will have to use three, volume, bass, and treble. And big MCU will be used also such as PIC16F877.

I thought if I have an IC capable of controlling volume, bass, and treble, with a built-in digital control interface for microcontrollers would be much better.

Can any one suggest IC numbers that do this work, especially those that fit into an ordinary stripped board ( Have 2.54 mm pin spacing ) ;)

Thanks to everybody :)

G4ME 24th May 2005 10:06 PM

Hey another PIC programer, you use the printer port and two resistors to build your programmer? Cause i did that last year in my Hardware applications using C class. We didn't get into controlling LCDs in class but I looked around PIC Lite programming software that we have in the department and saw some example code.

I was actually looking into using encoders (if found cheaply) and an IC to control volume. But if you got it working with digital pots, thats cool.

I haven't really read the entire Data sheet but check out the LM835, Its used for graphic EQ but i am sure you could use it to control bass and treble.

other then than that i haven't really researched it that much, but do you think you could enlighten a few of us here that know about pics with some Code. I would really love to get an LCD and just volume control on my GC project that i am starting in a few weeks.

The LM1036N is a tone volume control, connect it up to some digital pots, controlled by a pic with an LCD you are good to go. But it doesn't have the ability to be controlled by a micro controller itself.

wxn 25th May 2005 10:15 AM

LM1036 is inferior compared to a good discrete tone control. And you could use digital potentiometers too.

metal 25th May 2005 12:33 PM

Not helping :(
Hello G4ME

Yes, I use LPT port, but many resistors and a buffer IC...and some transistors to be able to program most PICs and EEPROMs.

I am not programming PICs with the ASM stuff, rather I am using PICBasic Pro compiler, better than ASM, and C compilers anyway, cuase it has commands to drive LCDs directly, rather than writing code for data lines, RS line, and E line. Also, I don't have plenty of time to gebug code, especially, that one I used to write in ASM when I first started with PICs.

Also, using digital pots is not a big deal here, cause there is a cool command "SHIFTOUT" that handles the sync serial data out and clock, and "BUTTON" command that makes it nice...

I just wanted an IC that connects to an MCU directly rather that using digital POTs to control LM1036, or TDA1524. And I have already made my volume control with PGA2310, cause I will use it for my next gainclone, with STK4191.

For example, LA2650 bass boast IC is controlled using MCUs or Microprocessors, but unfortunatelly, is not available in my country.

And by the way G4ME, if you need any help with MCUs and LCDs, please don't hesitate to contact me :)

Have a nice day

macboy 25th May 2005 02:58 PM

I have used the LM1036 in a low-end application. It controls volume, bass, treble, and balance using DC voltages as inputs. These voltages are usually derived from simple pots, but you could use digital pots, or DACs instead. It does not have stellar performance, so you would probably not want to use it in a gainclone.

You would probably get better performance, as wxn suggested, by using a classical Baxandall tone control, replacing the pots with digital pots (of good quality). Many digital pots use either a bus (I2C) or can be daisy-chained, so you do not neet to have separate control lines for each one, saving a lot of I/O pins on your uC. This is the option that I would investigate first.

Another option is to use a DSP like the Texas Instr TAS3004. This single chip has a stereo ADC, DSPs for tone control and 7-band EQ (and other stuff), volume control, and stereo DAC. It's analog in and analog out, so you don't need any other digital audio chips, just a microcontroller to control it. You don't need to know DSP theory either... you simply specify parameters for each function that the chip performs and it does it. You may not like the idea of adding a generation of analog/digital/analog conversion, but this will perform infinitely better than the LM1036.

A few companies used to make digitally control analog tone controls, but they don't seem to be available now. They had been used primarily in car stereos, but these days they all have some kind of DSP to do that work (it's actually cheaper).

metal 26th May 2005 05:50 PM

Hello Macboy

Good idea you had, TAS3004, that means I have to use some PCBs, and I really hate designing PCBs, but still a nice idea, as long as I have PROTEL DXP 2004, eagle, proteus...In deed I have them all, and Orcad 10.0 is included, but each time I set to use one of them, I go crazy, so I prefer the old fashoned stripped boards, less expensive too.

A PIC with built-in DACs will be very nice, 3 channels, and as you guys suggested TDA1524, or LM1036, will perform nice, and fairly good, I liked that idea in deed.


PKS 26th May 2005 06:24 PM


Very interesting.. but my programming skills are poor:(
See that you are using pga 2310's, and i have 2 stk fore sale, or for exchange(sorry my bad english, i am norwegian). i like opa's!!:D :D

just mail me!!


wxn 26th May 2005 06:40 PM


Originally posted by metal
and as you guys suggested TDA1524, or LM1036, will perform nice, and fairly good, I liked that idea in deed.
No, they will be just acceptable at best.

Sashi 26th May 2005 07:26 PM

TDA7439, should fit your bill.

ble0t 26th May 2005 07:42 PM

You could also check out the Maxim chips...

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