MikroBasic to PBP Pro: Boost mode SMPS

[jmgelba]

The code below will flash the LED but not create a pwm output. I'm guessing its because there are fractions and not integers to work with thus creating 0's and other odd results.
The convert to voltage portion works fine - I changed it, but the rest needs work still.

       temp=0      ADCIN 0, temp
      'write 40, temp
      
'convert to voltage
      v_feedback=temp                                                 'put ADC in float
                                                                               'v_supply=v_feedback/1024
      v_supply = 1024/v_feedback * 10                            'find supply % of vref
                                                                               'v_supply=v_supply*supply_multiplier  'find supply volts
      v_supply = v_supply * supply_multiplier / 10
      write 60, v_supply
      
'calculate rise time
      t_rise=L_Ipeak / v_supply                                       'find rise time @ supply volts for L/Ipeak
                                                                               ' = 68/24 = 2.833uS (example = 24vin)
'calculate CCPR1L:CCP1CON<5:4>
      SMPS_duty=t_rise*osc_freq                                    'find duty cycle value
                                       '2.833*48 = 136
      final_duty=SMPS_duty                                            'convert to byte
      
'calculate period
      t_period=t_rise*133/100                                         'dutycycle = .75period
                                                                                '2.833*133/100 =  3.767uS
'calculate PR2
      SMPS_period=(t_period/period_multiplier)                   'find period value
                                                                               '3.767/(4/48) = 45.2
      final_period=SMPS_period-1                                    'put in byte
                                                                         ' = 44.2
'put in register masks
      high_duty=(final_duty>>2)        'high 6 bits in CCPR1L
      low_duty=(final_duty<<6)         'low two bits for CCP1CON
      low_duty=(low_duty>>2)           'shift back to CCP1CON<5:4>
      low_duty.3=1                     'PWM configuration bit
      low_duty.2=1                     'PWM configuration bit




main:
CCPR1L=high_duty       'flash LED to show alive
CCP1CON=low_duty
portc.0 = 1
pause 100
portc.0 = 0
pause 100
GOTO main

[Ioannis]

I see an error on your PBP program

define OSC 48temp VAR word

should be

DEFINE OSC 48
temp VAR word

though I had no time to check all of your code.

Ioannis

[jmgelba]

Oops - thats a copy/paste error!!

Basically, I need help setting up a CCP for PWM operation - I have never done it.

Searching for examples...

[Ioannis]

This is for 16F1827 chip I use:

  CCP1CON = %00111100          'Control of CCPx modules
  CCP2CON = %00000000
  CCP3CON = %00000000
  CCP4CON = %00000000
  CM1CON0.7=0
  CM2CON0.7=0
  
  CPSCON0 = 0
  CPSCON1 = 0 
  
  DEFINE CCP1_REG PORTB
  DEFINE CCP1_BIT 3    
  ccptmrs=0
  pr2=249
  ccp1con=$0C
  t2con=%00000110

DACCON0 = 0

HTH,
Ioannis

[jmgelba]

I didnt know you needed to add defines. I assume CCP1_BIT 3 = PORTB.3 in your example?
Is DACC0N0 = 0 the same command as CMCON = 7? (turn off all comparators) or is it turn off all ADC's?

[jmgelba]

Ok, I understand everything up until this:

ccp1con=$0C

The pwm is already turned on as per the CCP1CON line.

[jmgelba]

Frustrated. Not sure what I am missing now. The CCP1 pin is always high, LED flashes correctly.

DEFINE OSC 48
DEFINE ADC_BITS 10
DEFINE ADC_CLOCK 3
DEFINE ADC_SAMPLEUS 50
DEFINE CCP1_REG PORTC
DEFINE CCP1_BIT 2   


final_period var byte
final_duty var byte
high_duty var byte
low_duty var byte


ADCON1 = 00001011
ADCON2 = 00000011


TRISA = 00001111
TRISB = 01110000
TRISC = 00000000
CMCON = 7


CCP1CON = 00111100
PR2 = 44
high_duty=(final_duty>>2)        'high 6 bits in CCPR1L
      low_duty=(final_duty<<6)         'low two bits for CCP1CON
      low_duty=(low_duty>>2)           'shift back to CCP1CON<5:4>
      low_duty.3=1                     'PWM configuration bit
      low_duty.2=1                     'PWM configuration bit
CCPR1L=high_duty
CCP1CON = $0C
T2CON = 4


main:
PORTC.0 = 1
pause 500
PORTC.0 = 0
Pause 500
goto main