Pic18f2320

[suded]

Hi,
I have 18F2320 has anyone used HPWM on this PIC? I have EPIC programmer is ok to program this chip?
I looks it has 16 bit PWM can I use it for 8 bit only? has anyone used both pwm's since it has two?
Regards,
Suded

[mpgmike]

You can use the HPWM command or you can manually control the PWM function. In the Data Sheet in the CCP section, PWM subsection, the ASM code is listed for firing up TMR2, activating the PWM, then controlling it from there. In order to use the PWM function at any higher than 8-bit resolution, you have to do it manually. You will be controlling the Duty Cycle with CCPR1L & CCPR1H for PWM Channel 1 and CCPR2L & CCPR2H for Channel 2. PBP3 only works with 8-bit control over PWM.

Mike Holler

[mpgmike]

The following is used on a PIC16F1824. Check your Data Sheet to double check the Special Function Registers as applicable to your chip:



; --- *** Timer 2 SFRs, Used for PWM Period *** --------------------------------
T2CON = %01111011 ;.2 = 1/0
PR2 = %11111111
PIE1.1 = 0 ;TMR2IE


; --- *** CCP1 PWM SFRs *** ----------------------------------------------------
CCP1CON = %00001100


DutyCycle VAR WORD
CCPR1L = DutyCycle.LOWBYTE
;HIGHBYTE comes from bits in CCP1CON


;Fill in other pertinent set-up data.


Label:
PIR1.1 = 0 ;TMR2IF
PIE1.1 = 1 ;TMR2IE
T2CON = %01111111 ;Turns TMR2 ON
do
loop while PIR1.1 = 0 ;TMR2IF
PIR1.1 = 0 ;TMR2IF
DutyCycle = ;desired PWM


Hope this helps.

[suded]

Hi Mike,
Thanks for your help, I need to use directly from PBP, I have an older version.
I'm thinking of using a single PWM PIC like PIC18F1320 to control two analogue values then use sample and hold get two outputs.
Regards,
Suded

[mpgmike]

Frequency is controlled by the scaler in T2CON and the value of PR2. The setting I'm using provides for the slowest frequency possible with my OSC speed; PR2 = $FF. The reason I do this the long way is PBP3 will actually toggle PR2 between 2 values to deliver the frequency requested in the HPWM command (HPWM 1,DutyCycle,Frequency). I needed a consistent cycle-to-cycle period timing and couldn't achieve it with HPWM.