Are more than 8pots directly connected to pic18f452 possible without additional ic's ?

Design Concepts
1

Hi guys,

i checked the inside of an old DJ controller called kdj500( Designed for Traktor DJ Software) and found 13 analog pots and fader, all connected directly to the pic controller 18f452. 

Within The desciption of pic based Core Here on ucapps Website i saw this:

Analog sources (like pots) can be connected to this port (8 pots maximum). If multiplexed via AIN module, up to 64 pots can be scanned. Remember that All unused analog inputs must be conncted to ground. There are also some application which use this pin as digital in- or output (mostly described in REAMDE.txt or setup_*.asm file)

 

is there in way that will work without additional ADC ic’s?

I cannot find More information and need your help.

br ranger930

 

2

PIC18f452 has only 8 analog inputs as you can read in the data sheet: https://ww1.microchip.com/downloads/en/DeviceDoc/39564c.pdf

Are you sure, that there is no chip such a 4051 multiplexer (which is not an ADC, such a “switch”) between pots and analog inputs?

Best Regards, Thorsten.

3

Hi Thorsten, thanks for your answer.

I have checked the PCB again and there are no multiplexers  on the PCB , only ic’s for digital inputs and outputs to drive LEDs.

There are 13 analog pots there, all analog inputs of the pic are directly connected to 8 of these pots (all with a resistor AS pull up , or pull down, i don’t know) the other pots are connected in the same way, but to the following signal pins of the pic: pin36 -pin40, rb3-rb7.

Any ideas ?

BR ranger930

4

These are digital IO pins, I guess that they are only used to check for full left/full right turns.

Good enough for DJ fake pots! 

Best Regards, Thorsten.