Music Input

[malc-c]

Hi,

I'm developing a disco light rig and need some advice. I want to connect the device to the line out from a CD player (typically 1v RMS peak to peak) via a lowpass filter that is then fed through a peak filter (CCt can be supplied if required) to pin RA2 of a 16F628a PIC

As I already have switches on some PORT A so I only want to set AN2 (RA2) to analogue.

Now I did try and use the POT comamnd, but realised that this wouldn't work as there is no real means of charging acapacitor, so I looked at the ADCIN command, and this is where my lack of experience shows. Here is the top section of my code

PORTA = 0 ' declare port level BEFORE port direction = safe power-on
CMCON = 7 ' PortA Digital inputs
DEFINE ADC_BITS 8
CCP1CON = 0 ' PWM off
VRCON = 0        ' Voltage reference disabled
OPTION_REG.7 =    0
ADCIN 2, M

As I was using switches on port A I had used CMCON = 7 to make all ports didgital, so how do I change this so that RA2 is analogue and the rest digital. I also assume that I have the correct syntax ADCIN 2, M to put the resulting value (0 - 255) into M? The idea then is to include a line that states if the value of M is above a threshold it will run to the step in the pattern, if its below it simply loops until M is above the threshold.

I welcome your comments

[peterdeco1]

Hi Malcolm. I did something similar a while back with a 12F675 and a portable radio. This program flashes several LED's with the beat of the music. Audio was taken from the audio feed to the volume control. The use of the ADC command automatically converts the port to analog.

ANSEL = 0 'all inputs digital
CMCON = 7 'comparators off
DEFINE OSCCAL_1K 1 ' Set OSCCAL for 1K device to accurize osc
@ DEVICE MCLR_OFF, INTRC_OSC, WDT_ON, BOD_ON, PWRT_ON, PROTECT_ON
TRISIO = %11111111 ' all inputs for now
'high & low commands convert to outputs
X VAR BYTE 'adc variable

START:
ADCIN 0, X
IF X > 2 Then High GPIO.2 'TURN ON LED'S ON GPIO.2
IF X <=2 Then Low GPIO.2 'OFF LED'S
GOTO START

[malc-c]

Thanks for the reply,

Sounds good (sorry no pun intended), I'll have a play and see what I can do.

Cheers

[Melanie]

If and when you get ADCIN to work with a 16F628A, come back and tell us how you did it. That PIC hasn't got any ADC's...

[malc-c]

Sorry I dow to your superior knowledge.. so what's an analogue comparator input then.. will it not do the same thing... ??

[Acetronics2]

Hi, Malc

Some years ago, Elektor committed such a project with a 16F84 ... you could have a look to their input stage ...

16F628 is a "bigger" '84 ...no ???

Alain

PS : Project 000107 ... note everything Downloadable ...