My project is starting

[cncmachineguy]

and I have a need for some advice/suggestions

First let me say if this should be in a different topic, PLEASE move it.

Heres the overview:
I have been working on a machine to cut foam for R/C planes. I am working on this with another guy in Ohio, so not close to me. We have our machines ready now, and of course I am behind on the electronics.

We will be using EMC2 as our machine controller. Using 2 parallel ports, we will be controlling 6 steppers, 1 spindle, and 1 hot wire. The machine also has travel limits on each end of each axis.

I have 2 interface cards based around a 16f1947, 1 for each parallel port. these are identical. each card will be responsible for passing step/dir signals through for up to 4 motors(only 3 needed in our app), enable all 4 drives independantly from a single enable output from EMC2. All the limit switches for the 4 axis will be monitored by the card. disable a drive if a limit is hit and pass the home switches back to EMC2.

Ok, enough of the basics, if anyone is intrested in more detail, just ask.

On to the problem.
Talking to a PIC from a serial port will be new to me. Bootloaders are new to me.

I can write the basic program to just do the above without any problem, but I have much more in store for this card. So I need to get the basic part done and send 2 cards to Ohio. My buddy has no need for a programmer so to get him updates I really want to send him cards pre loaded with a bootloader able to work from rs232 port.

I don't really know how to get started is my problem. Should I first play with a bootloader and get the LED blinky to work? Should I start with a serial comm program and get that to work? What bootloader should I use? If I need to change any config stuff, will I be able to do that with a bootloader?

[ScaleRobotics]

I looked to my favorite bootloader, Tiny Pic Bootloader http://www.etc.ugal.ro/cchiculita/so...bootloader.htm, but it does not cover your chip. So I looked around, and found a Microchip Ap Note AN1302. It talks about programming multiple chips through the I2C port. I have not had a chance to read it yet, but this might be good for you. Specially since you need to program two or three chips. It has the hex files, and the PC program here: http://www.microchip.com/stellent/id...pnote=en546181

With the PIC18 devices you can do a run-time config http://www.picbasic.co.uk/forum/showthread.php?t=4093

But not with PIC16 devices. So your configs need to be right the first time. But worst case, you could fedex new programmed PICs to your friend in Ohio, if you needed to change configs. (Well at least if it's not surface mount).

Edit: By the way, sounds like a very cool project. I am going to have to read more about EMC2. I hadn't even heard about it. What is the largest span you can hot wire? Can you post any pictures?

[cncmachineguy]

Thanks Walter, I will look into the APP note. But I will only have 1 chip per card. I did put an I2C port on board

As for sending chips back and forth, they are TQFP's. So that option is out. Worse case is I buy a pickit2 and send him to use while I get things going as I want them. Then He can send it back and I will be part of the PK2 club.

But A bootloader would be too cool, just email program and presto magic.

[cncmachineguy]

Edit: By the way, sounds like a very cool project. I am going to have to read more about EMC2. I hadn't even heard about it. What is the largest span you can hot wire? Can you post any pictures?

EMC2

We have designed it to be able to process a 24 x 48 inch piece of foam with the mill or the wire, No pics just yet, but we are about a week out with those. We jumped the gun back in july/aug with pics of our first prototype. so now he is gunshy. Also we completly redesigned it from the first one.

[ScaleRobotics]

Sorry, that won't work

"We can, however, use PC software if we use a device that will act as a master I2C device controlled by PC software. We used the PICkit™ Serial analyzer configured as an I2C master device."

Since you need a Pickit serial analyzer to make it work, it kind of defeats the purpose. Maybe this one, AN1310: http://www.microchip.com/stellent/id...pnote=en546974

[cncmachineguy]

Just skimed over AN1310. It sounds awesome, but of course it says it uses USART1 and of course I am setup for USART2

Maybe the firmware can be modified? I will also look at the alternatives listed at the end of the note.

[cncmachineguy]

Maybe the best choice here is to skip the bootloader for now. It may be I am just a bit overwhelmed with the choices, but getting it to work is really more important then being able to upgrade the firmware in the field. Maybe on the next board rev I will look at changing the usart's but I think I wanted the pins to make something else easy. I don't remember right now.

[mackrackit]

EMC2...
Have you tried the new version using Ubunu 10 yet?

JDM
I do not normally sugest them but I have bult them into a board for cases like this. Being built in and tweaked for one chip helps their short comings.
Then use PikLab to squirt the hex.

[cncmachineguy]

Haven't tried the new version yet, but I have managed to get the live install on a USB drive and ready to install so I don't need a cd player. I imagine I will have it running over the holiday.

Jdm- I had never even heard about this programmer until I joined this forum. Building it onto the card is a cool idea, but it missed this rev. I guess I could just build one, but will it really be cost effective when a pickit2 is only $35 for just the programmer?

As an extra bonus, if I could do all this with ubuntu 10 from the machine controller, now that would be something.

Alas, I think it's prolly best to leave the field upgrade out of the equation for just now. And if I do that, I don't even need serial comm. Now I can just focus on getting the basic function done so the machines will work.

[ScaleRobotics]

Darrel has a post in here somewhere that says how many instruction cycles an ASM type interrupt has, but I am having a heck of a time trying to find it. I remember it being substantially fewer than PBP type, but can't remember the number. I will try looking some more.

[ScaleRobotics]

EDIT: OOPS, you are correct, you would need IOC for portA ... Sorry...
__________________________________________________ _______________
RAC_INT is for portA.

(from http://darreltaylor.com/DT_INTS-14/intro.html )
RAC_INT -- RA Port Change (for port A)
RBC_INT -- RB Port Change Interrupt (for port B)
RABC_INT -- RAB Port Change (for port A or B)

Here is a small example for RAC_INT , but it's just for a push button.

http://www.picbasic.co.uk/forum/show...2818#post82818

[cncmachineguy]

thats OK Walter, you had me thinking for the last hour or 2! (Now have to reset all the smoke alarms)

But back to it, any thoughts on my timing? Anyone? My brain is still locked about this. I want to draw me some timing diagrams, but it seems I have become so dependent on puters, I don't have any suitable graph paper to do so with. I am somewhat of a stickler when it comes to these things.

[mackrackit]

Doin' what I can

[cncmachineguy]

Inspired by Daves wonderful gift, I worked out some timing in my schmatic program (with snaps). It looks to me with 5uS interupts, I will not miss a single step. I will strech them sometimes and shrink them sometimes, but thats no problem. And I still have 40 instructions between interupts. Well prolly more like 30 when you account for the interupt handler itself.

So I think I am off to the races now!!

[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?