My project is starting

[ScaleRobotics]

Ok, I found a scheme of the parallel port for EMC

http://gramlich.net/projects/cnc/controller/index.html

Oops, I see your answer now. Thanks Bert!

[cncmachineguy]

I have a problem, not sure where it is. My gut feeling is its with the background things that may be happing when using DT-INT. Here is the entire program.

' Name        : Interface card.pbp
' Compiler    : PICBASIC PRO Compiler 2.6A
' Assembler   : MPASM
' Target PIC  : 16F1947
' Hardware    : PIMill Interface 
' Oscillator  : internal
' Keywords    : 
' Description : PICBASIC PRO program to interface parallel port
' to 4 stepper drives and limit switches
'

'
' 
'
' Configure ports
' 
' 
ANSELA = %00000000  'port A all digital
ANSELE = %00000000  'port E all digital
ANSELF = %00000000  'port F all digital
ANSELG = %00000000  'port G all digital

CM1CON0 = %00000000  'No comparaters
CM1CON1 = %00000000
CM2CON0 = %00000000
CM2CON1 = %00000000

' preload latches before setting direction
LATB = %00000000
LATC = %00000000
LATD = %00010000 'LED's 0 for red, 1 FOR GREEN should start red
LATF = %00001111 ' low nibble is drive enable. 1 disables
LATG = %00000000

' I/O direction

TRISA = %11111111'step and dir inputs
TRISB = %11000001'7-0 icsp,icsp,h4o,h3o,h2o,h1o,estopO,enable In
TRISC = %00000000'step and dir outputs
TRISD = %00000000'led6,i2c,i2c,led5,led4,led3,led2,led1
TRISE = %11111111'ls4,lsh4.ls3,lsh3,ls2,lsh2,ls1,lsh1
TRISF = %00010000'spindle dir,servo out,dac out,flood input,4en,3en,2en,1en
TRISG = %11100111'x,x,icsp/mclr,rly2,rly1,Rx2,Tx2,DI




'REMOVE THIS LINE IF NOT SETTING THE CONFIGS IN CODE SPACE
@ __config _CONFIG1,_FOSC_INTOSC & _WDTE_OFF & _PWRTE_OFF & _MCLRE_OFF & _CP_OFF & _CPD_OFF & _BOREN_OFF & _CLKOUTEN_OFF & _IESO_OFF & _FCMEN_OFF
@ __config _CONFIG2,_WRT_OFF & _VCAPEN_OFF & _PLLEN_ON & _STVREN_OFF & _BORV_25 & _LVP_OFF

'Internal osc setup
OSCCON = %01110000 'clock is 8 meg. turn on PLL for 32 meg clock
DEFINE OSC 16 ' 32 meg not allowed according to book. be sure to double things that need this

'Variables
LED0    VAR LATD.0   ' Assign name "LED" to PORTD
LED1	VAR LATD.1
LED2	VAR LATD.2
LED3    VAR LATD.3
LED4    VAR LATD.4
LED5	VAR LATD.7
CNT 	VAR BYTE

ENALL   VAR PORTB.0
BSRSTORE VAR BYTE

EN1     VAR LATF.0
EN2     VAR LATF.1
EN3     VAR LATF.2
EN4     VAR LATF.3
ASM
	#DEFINE EN1A LATF,0 'stuff for testing
	
ENDASM
wsave VAR BYTE $70 SYSTEM
INCLUDE "DT_INTS-14.bas"     ' Base Interrupt System
'INCLUDE "ReEnterPBP.bas"     ' Include if using PBP interrupts

ASM
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler   TMR2_INT,  _FiveMicroSec,   ASM,  yes
    endm
    INT_CREATE               ; Creates the interrupt processor
ENDASM

'5.0 uSec OR 200,000 Hz INTERRUPTS

T2CON = %00000100         'Prescaler = 1:1, TMR2ON

'PRELOAD 223 "FROM MULTI-CALC"
PRELOAD     VAR byte
PRELOAD =  239 ' FROM TESTING TO FIND THE RIGHT NUMBER
TMR2 = PRELOAD

@ INT_ENABLE  TMR2_INT     ; enable Timer 2 interrupts

Main:      'DO WHATEVER YOU WANT HERE
 
  
  IF CNT=200 THEN
	TOGGLE EN2
	TOGGLE LED1
	CNT=0
  ENDIF
  TOGGLE LED2
GOTO Main


	
'---[TMR2 - interrupt handler]--------------------------------------------------
FiveMicroSec:
	TMR2 = PRELOAD  'THIS LINE
	TOGGLE EN1      'AND THIS LINE
	CNT =CNT+1      'WITH THIS CREATE A INT ROUTINE EVERY 4.99uS
'	LATC = PORTA    'ADDING THIS LINE CHANGES THE TIME TO 5.245uS!!
                    ' SO WHY DOES THIS CHANGE THE TIMING?@ INT_RETURN

Now It doesn't make sense to me. I am running a 32mHz clock. 5 uS interupt should takes 160 clock cycles, or 40 asm instructions. my interupt routine has 3 PBP instructions when working and 4 when I add the LATC=PORTA line. I can't imagine that would be 40 lines of ASM. I have tried to do this with a pure ASM handler, but I can only get it to work if I toggle LATA instead of LATF. I am sure this is a bank select issue. I can work through that if I must, but I would really like to use PBP instead.

Maybe all the time is taken up with the entry and return? Also note the large disparity between what I thought the preload should be and what it is.

[mackrackit]

Not much help but

OSCCON = %01110000 'clock is 8 meg. turn on PLL for 32 meg clock
DEFINE OSC 16 ' 32 meg not allowed according to book. be sure to double things that need this

I think should be

OSCCON = %11110000 'clock is 8 meg. turn on PLL for 32 meg clock
DEFINE OSC 32 ' 32 meg is allowed according to book. be sure to double things that need this

??
But I could be wrong

[rmteo]

A timer preload of 239 indicates you have only 16 CPU (or ASM) cycles available - looks like 24 cycles are consumed by overhead.

[cncmachineguy]

And I guess it makes sense that the overhead is in entering the interupt. Otherwise those cycles would be part of the "timer cycle" and not have to be adjusted for in the preload. I think at this point I have 2 options, either use pure ASM interupts and/or increase my timing to 8uS. Maybe I will look at how many instructions it takes to enter the interupt if using pure ASM. This will be the deciding factor I guess. Clearly there is some lag needed to enter the handler, but is it 24 cycles?

[cncmachineguy]

@Dave, You know I would have bet my left pinky 32 was NOT in the list when I looked up DEFINE OSC, but low and behold it sure is. Thanks for making me look again. As for the bit 7 of OSCON, the way I read it is it is ignored if PLL is enabled in my config-which I think I did. Won't hurt to set it though.

[mackrackit]

the way I read it is it is ignored if PLL is enabled in my config-which I think I did. Won't hurt to set it though.

Yup, my mistake.