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Old 2nd January 2004, 12:48 PM   #1
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Default Digital Volume Control

Can I use the LM1972, at http://www.national.com/pf/LM/LM1972.html and control it with two pushbuttons, one for up and one for down?

If not, would any National, Maxim or TI chip (I would like to get samples) work for what I want to do?

Thanks, Mike
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Old 2nd January 2004, 01:42 PM   #2
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Default Re: Digital Volume Control

Quote:
Originally posted by soundNERD
Can I use the LM1972, at http://www.national.com/pf/LM/LM1972.html and control it with two pushbuttons, one for up and one for down?

If not, would any National, Maxim or TI chip (I would like to get samples) work for what I want to do?

Thanks, Mike
No, you would need a microcontroller (such as a PIC or AVR) to generate the serial data required by most of these devices. Checking the datasheets will tell you all you need to know about the format and timing, etc...

An exception to this is the Dallas DS1802, which can be controlled by pushbuttons. I considered it for use in my preamp, you can read what I though here: http://www.mhennessy.f9.co.uk/preamp...e_research.htm

Cheers,

Mark
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Old 2nd January 2004, 08:01 PM   #3
deandob is offline deandob  Australia
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Default PIC volume control

I have a working PIC schematic & code for the LM1972 as a volume control - if needed I can email it to you. The code allows the PIC to be connected to a PC serial port & control the volume through software on a PC.

Regards,
Dean
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Old 3rd January 2004, 12:24 PM   #4
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Default Re: PIC volume control

Quote:
Originally posted by deandob
I have a working PIC schematic & code for the LM1972 as a volume control - if needed I can email it to you. The code allows the PIC to be connected to a PC serial port & control the volume through software on a PC.

Regards,
Dean
Could you e-mail me the info also? matttcattt@yahoo.co.uk

Thanks
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Old 3rd January 2004, 01:16 PM   #5
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Default Re: Re: Digital Volume Control

Quote:
Originally posted by mhennessy


No, you would need a microcontroller (such as a PIC or AVR) to generate the serial data required by most of these devices. Checking the datasheets will tell you all you need to know about the format and timing, etc...

An exception to this is the Dallas DS1802, which can be controlled by pushbuttons. I considered it for use in my preamp, you can read what I though here: http://www.mhennessy.f9.co.uk/preamp...e_research.htm

Cheers,

Mark
No you don't need a microcontroller -- but it is easier with one -- the LM1971,2,3 are synchronous devices so you either toggle the clock line yourself or use a slow-moving 555, an 8-bit "counter" and a "Parallel in Serial Out" shift register (74HC595) -- bring the Load line "LOW", set the address of the LM1972 (0,1,2), by transmitting 8 bits, then transmit the dB/mute setting (second 8-bits), bring the Load Line "High". Parts to do this are about $1.00.

If using a pushbutton for up down, consider how many milliseconds you want the '555 to run for the full gamut.

"Software" in solder -- the old fashioned way -- still works as Steve Ciarcia is wont to say.
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Old 3rd January 2004, 07:58 PM   #6
deandob is offline deandob  Australia
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matttcatt, you have mail.

Regards,
Dean
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Old 3rd January 2004, 08:17 PM   #7
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First, I ordered a sample of the dallas chip.

Second, I would like that microcontroller volume control code and schematic.

e-mail me at webmaster@electronet.5u.com

Thanks!
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Old 3rd January 2004, 08:24 PM   #8
TheTrax is offline TheTrax  Belgium
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Hi
can you tell me the chip type number and the kind of microprocessor you want to use ?
I can help you making ASM assembler routines if you want ?
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Old 4th January 2004, 04:00 AM   #9
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Well, i donno 2 much about microcontrollers. 2 be honest, ive never used one before. So, whatever is cheap and can be eaily bought. (as always i like free samples).

-Mike
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Old 4th January 2004, 04:05 AM   #10
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Default Re: Re: Digital Volume Control

Quote:
Originally posted by mhennessy


No, you would need a microcontroller (such as a PIC or AVR) to generate the serial data required by most of these devices. Checking the datasheets will tell you all you need to know about the format and timing, etc...

An exception to this is the Dallas DS1802, which can be controlled by pushbuttons. I considered it for use in my preamp, you can read what I though here: http://www.mhennessy.f9.co.uk/preamp...e_research.htm

Cheers,

Mark

And let me add, that your pre-amp is really hardcore-style-awesome ... i plan to build something similar to it when i have abilities even close to yours
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