Pic25k20 PWM Amicus board incorrect freq

[Tim]

Hi

I'm having loads of trouble with my the 25K20 setting up the PWM.

I have a IR remote receiver and never have trouble getting a 38kh pwm going to drive an IR led.

But the 25K20 is impossible.

Hi, its great to see you visiting our forum. Why not try Proton Compiler for FREE? Download the FREE version of Proton Compiler, Its called Amicus18 and its available from HERE Already using proton Compiler??? Get rid of these pesky messages... get LICENSED USER STATUS

I have tried it running at 64mhz as it is by default on the Amicus board using pwm settings from a web site I have used in the past. But no action. So Looked at what is produced on in ISIS to a signal input set at 38khz and its way out.
Changed it to 16mhz by reprogramming and still wrong

Double checked ISIS by using at 12f683 and some code I had. It was the same as the pulse generator. So I know ISIS is working ok.

Basically I have tried every thing including the HPWM Command and nothing.

HELP!! Any ideas?

[captainslarty]

Hi Tim
It would help if you posted at least the configuration you are using to setup the appropriate registers to set your PWM value.
Also, have you looked at the ouput on actual hardware on a scope ? - if so what were the results ?

[Tim]

This is the code I used

Its the same pwm set up as I have used on a 18f4520

;-------------------------------------------------------------------------------;**** Added by Fuse Configurator ****
; Use the Fuse Configurator plug-in to change these settings


	Device = 18F25K20


	Declare Reminders Off
	@ CONFIG_REQ = 0 ; Override Compiler's configuration settings
	Asm-
	Config FOSC = HS	;HS oscillator
	Config FCMEN = OFF	;Fail-Safe Clock Monitor disabled
	Config IESO = OFF	;Oscillator Switchover mode disabled
	Config PWRT = On	;PWRT enabled
	Config BOREN = OFF	;Brown-out Reset disabled in hardware and software
	Config BORV = 22	;VBOR set to 2.2 V nominal
	Config WDTEN = OFF	;WDT is controlled by SWDTEN bit of the WDTCON register
	Config WDTPS = 1	;1:1
	Config CCP2MX = PORTBE	;CCP2 input/output is multiplexed with RB3
	Config PBADEN = OFF	;PORTB<4:0> pins are configured as digital I/O on Reset
	Config LPT1OSC = OFF	;Timer1 configured for higher power operation
	Config HFOFST = OFF	;The system clock is held off until the HFINTOSC is stable.
	Config MCLRE = OFF	;RE3 input pin enabled; MCLR disabled
	Config STVREN = OFF	;Stack full/underflow will not cause Reset
	Config LVP = OFF	;Single-Supply ICSP disabled
	Config XINST = On	;Instruction set extension and Indexed Addressing mode enabled
	Config Debug = OFF	;Background debugger disabled, RB6 and RB7 configured as general purpose I/O pins
	Config CP0 = On	;Block 0 (000800-001FFFh) code-protected
	Config CP1 = On	;Block 1 (002000-003FFFh) code-protected
	Config CP2 = OFF	;Block 2 (004000-005FFFh) not code-protected
	Config CP3 = On	;Block 3 (006000-007FFFh) code-protected
	Config CPB = OFF	;Boot block (000000-0007FFh) not code-protected
	Config CPD = OFF	;Data EEPROM not code-protected
	Config WRT0 = OFF	;Block 0 (000800-001FFFh) not write-protected
	Config WRT1 = OFF	;Block 1 (002000-003FFFh) not write-protected
	Config WRT2 = OFF	;Block 2 (004000-005FFFh) not write-protected
	Config WRT3 = OFF	;Block 3 (006000-007FFFh) not write-protected
	Config WRTC = OFF	;Configuration registers (300000-3000FFh) not write-protected
	Config WRTB = OFF	;Boot Block (000000-0007FFh) not write-protected
	Config WRTD = OFF	;Data EEPROM not write-protected
	Config EBTR0 = OFF	;Block 0 (000800-001FFFh) not protected from table reads executed in other blocks
	Config EBTR1 = OFF	;Block 1 (002000-003FFFh) not protected from table reads executed in other blocks
	Config EBTR2 = OFF	;Block 2 (004000-005FFFh) not protected from table reads executed in other blocks
	Config EBTR3 = OFF	;Block 3 (006000-007FFFh) not protected from table reads executed in other blocks
	Config EBTRB = OFF	;Boot Block (000000-0007FFh) not protected from table reads executed in other blocks
	Endasm-


	Declare Reminders On


;**** End of Fuse Configurator Settings ****
;-------------------------------------------------------------------------------




    Xtal 4
   
    
    Declare Create_Coff = On


'    T2CON = 0b00000100; // prescaler + turn on TMR2;
'    PR2 = 104;
'    CCPR1L = 0b00110100;  // set duty MSB
'    CCP1CON = 210; // duty lowest bits + PWM mode


    PR2 = 25                                    ' Set PWM Period for approximately 38KHz
    CCPR1L = 13      		                    ' Set PWM Duty-Cycle to 50% 
    CCP1CON = %00001100                         ' Mode select = PWM
    T2CON = %00000100		                    ' Timer2 ON + 1:1 prescale ratio
    
        
 ;   HPWM 1, 127, 38000
        
    Output PORTC.2
    
    While 1 = 1
   
    Wend

Here is a capture of the scope from isis for various CPUs running and a ref pulse from a pulse generator
The next snap is with a 18f4520 replacing the 18f25k20 as you can see all except the 25k20 look fine

I have an old tube scope and a pico scope. I'm working up at the house as the office is to cold and has to much junk in it, so no room for the big scope and the pico is temperamental.

All I want is a 38khz signal to try something out. I would have to go out and by a parts to build a new board and as its the week end I will not get them. The client is waiting and I cannot say I have to wait for Tuesday for parts.

I thought the Amicus would be fine but the pic used has issues

[captainslarty]

Hi Tim
should you not be using CCP2CON ? for standard (ie non enhanced) for standard PWM ?
At first glance CCP1CON sets enhanced mode.

See section 11.0 of datasheet ?

otherwise your calcuations look fine - I get a freq of 38.46 Khz... (on the spreadsheet I did)
I can send you a PWM calc spreadsheet if you like ?

Joe.

[Tim]

Hi Joe

That might be the problem.

Yes please to the spreed sheet

BTW I have found a remote control kit that has pic's in sockets in stock locally so will pick one up shortly

http://www.maplin.co.uk/infrared-2-c...ler-kit-220034

[captainslarty]

Hi Tim
Here is the spreadsheet -
It as rough as a bear's arse lol - but does the main job.
Hope it helps -

(Did you really write that - or were you testing the device ?? )
Just ribbing ya dude !

Hope ya get it sorted mate, otherwise, send me the DSN (I have a legal Proteus FULL) and I will check it out.

Joe.

[pic-ignorant]

Off the top of my head, the ECCP should be fine to use if you set PSTRxCON = %00000001 to output the PWM pulse to P1A (CCP1 pin).

[captainslarty]

Off the top of my head, the ECCP should be fine to use if you set PSTRxCON = 000001 to output the PWM pulse to P1A (CCP1 pin).

Hi John
thats a good point - it also reminds me that I never did do those pulse steering experiments - you just re-fired my interest in that one

[pic-ignorant]

Did you sort this out Tim?

[Tim]

No, its a sorry tale of wasted time.

I purchased a IR kit to save time. Thought, well at least I will have as starting point. They used a 12f629, in the Sender one the RX side. It turns out they came un-programmed. SO I wrote a small bit of code to do the 36khz I wanted. No luck at all. The signal was there at the right freq. Matched it to my TV's Remote that made the IR receiver chip I had work.

It turned out after checking the packing on the IR diode in the kit that it was not an IR diode after all. It was a IR transistor receiver! Replaced it with an IR diode I had and it started working. SO they sold a kit with non programmed parts and with the wrong parts.

In the end now I can do the job with a 10F200, for now though, its all software in a 12f629.