my project Capacitive Sensing LED dimmer 12F1822 via PWM

[Heckler]

Well, After posting here a couple of days ago fishing for someone who has had success setting up the Cap Sense module on the 12F1822, and getting no response, I did some searching and was finally able to get it going.

I found a couple of threads where HankMcSpank had tackeled it... (thanks hank)
Which led to another thread where some correcttions reggarding the use of TMR0 vs TMR1.
(I can't find either of those threads now or I'd post a link)

Any way here is a little project I have wanted to do and CapSense seems to work and makes it a bit simpler.

See attached schematic.

This is the LED I am using... http://dx.com/p/g4-1-2w-108-lumen-35...b-dc-12v-51269

Which makes use of Darrel's Instant Interrupts (thanks Darrel!). You will have to go get those include files from his web site dt.cambs.net

here is the code...

'****************************************************************
'*  Name    : UNTITLED.BAS                                      *
'*  Author  : Dwight and others                                 *
'*  Notice  : Copyright (c) 2013 [select VIEW...EDITOR OPTIONS] *
'*          : All Rights Reserved                               *
'*  Date    : 11/29/2013                                        *
'*  Version : 1.0                                               *
'*  Notes   :   PIC12F1822                                                *
'*          :                                                   *
'****************************************************************
#CONFIG
  __CONFIG _CONFIG1, _FCMEN_OFF & _FOSC_INTOSC & _WDTE_SWDTEN & _MCLRE_OFF & _CP_OFF & _IESO_OFF & _BOREN_OFF & _PWRTE_OFF
  __CONFIG _CONFIG2, _LVP_OFF
#ENDCONFIG

DEFINE  OSC 8                'tell picbasic what speed the oscillator is

INCLUDE "DT_INTS-14.bas"     ' 
INCLUDE "ReEnterPBP.bas"     ' Include if using PBP interrupts

OSCCON = %01110010         
                        '0 = 4x PLL is disabled
                        ' 1110 = 8 MHz 
                        '     0 = unused
                        '      1X = Internal oscillator


ANSELA = %00000100        'make port A.2 is analog
TRISA  = %00000100        'port A.2 is input
WPUA   = %00000000        'turn off weak pull ups

APFCON = %00000001        'Alternate Pin Function Control Reg (default %00000000)
                          'move CCP to PortA.5 (for PWM output)
OPTION_REG = %10000111     
                        '1 = All weak pull-ups are disabled (except MCLR, if it is enabled)
                        ' 0 = Interrupt on falling edge of RB0/INT pin
                        '  0 = Timer0 clock is internal cycle clock (Fosc/4)
                        '   0 = Increment on low-to-high transition on RA4/T0CKI pin
                        '    0 = Prescaler is assigned to the Timer0 module
                        '     111 = 1:256 Timer0 prescaler rate
                
T1CON = %11000001       'enable timer 1 (bit 0) & source the clock from the CPS module (bit 6 & 7 =11

CPSCON0 = %10001100     'set the CPS module highest frequency availabe (for vcc mode) + timer0 clock sourced from CPS module. (BIT 1)
                        '1 = CPS module is enabled
                        ' 0 = CPS module is in the low range. Internal oscillator voltage references are used.
                        '  00 = unused
                        '    11 = Oscillator is in High Range. Charge/Discharge Current is nominally 18 µA
                        '      0 = Capacitive Sensing Oscillator Status bit (only readable)
                        '       0 = Timer0 clock source is controlled by the core/Timer0 module and is FOSC/4

CPSCON1 = %00000010        '0010 = channel 2, (CPS2)

CM1CON0 = 0   ' COMPARATOR OFF
CM1CON1 = 0   ' COMPARATOR OFF

CPS2_PRESENT    var WORD
CPS2_THRESHOLD  var WORD
CPS2_LAST       var WORD

'       Software variables
'       ==================
Duty    VAR WORD
stepp   var byte


' ----------------[ I/O Definitions ]-----------------------------------
FET VAR PORTA.5  ' PWM output to control the FET switch

'       Software/Hardware initialisation
'       ================================
PAUSE 50                           ' OSC settle delay
Duty = 0
stepp = 5
hpwm 1,255,250                     ' Start with Light full ON
pause 1000
     
ASM
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler   TMR0_INT,  _Timer0_Int,   pbp,  yes
    endm
    INT_CREATE               ; Creates the interrupt processor
ENDASM
 
TMR0 = 0                  'clear  TIMER0
@ INT_ENABLE  TMR0_INT    'enable timer0 interrupts
'***********************************************************************
'------------------------------< Main program >-------------------------
Main:
pause 100   ' not a whole lot going on here
goto main

'*****************************************************************************
Timer0_Int:
@ INT_DISABLE  TMR0_INT   ' stop timer0 interrupts while we're in here
pause 25

CPS2_PRESENT = TMR1                                ' take a snapshot of Timer1's present count.
CPS2_THRESHOLD = CPS2_LAST - ((CPS2_LAST/10)*2)    ' this sets the 'trigger' up for a 20% diversion (finger press)
CPS2_LAST = CPS2_PRESENT                           ' store away the present timer0count for the next time we come into the interrupt routine

if cps2_present < cps2_threshold then
    stepp = stepp +1
    if stepp>6 then stepp=0            ' check for rollover
    lookup stepp, [0,1,16,64,128,255,255],duty  'choose level, 5 levels plus OFF
    if stepp=6 then 
        hpwm 1,0,1000    'off              ' arrive here when brightness is MAX
        pause 100                          '    So blink to let user know.
        hpwm 1,255,1000  'on
        pause 100
        hpwm 1,0,1000    'off
        pause 100
        hpwm 1,255,1000  'on              ' blink to show that you are at the highest level
    endif    
    hpwm 1,duty,250                    ' else set new level                       ' button pressed so increment stepp  
    pause 100
endif

pause 50      
TMR0 = 0                  ' clear TIMER0    
TMR1 = 0                  ' clear TIMER1
@ INT_ENABLE  TMR0_INT    ' re-enable timer0 interrupt
@ INT_RETURN   

end

enjoy! and tell me what you think (good or bad)