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.

[mackrackit]

I guess I could just build one, but will it really be cost effective when a pickit2 is only $35 for just the programmer?

Is this project a one off sort of thing? If so then the PicKit2 will be cheaper in the long run.

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

You can also use the PicKit2 on an Ubuntu box.

[cncmachineguy]

dave do you ever sleep?

About the project size, Of course we always hope somebody may want 1 besides us, at this point I am only focused on his and mine. For this I think pk2 is prolly best. I can even get him to buy his own!

I will prolly dig a little deeper into the I2C method. In the future it would be best to have a single serial connection to talk to both cards. I am sure there must be a way to not need the serial analyzer to do this. even if its a special built card that does rs232<->I2c. power levels can come from the target


yea Ubuntu!!!

[mackrackit]

dave do you ever sleep?

Sleep is for sissies.

[cncmachineguy]

I guess I must be, I seem to need at least 4-5 hours now days.

I got my cards in today So I will be building my cards tomorrow morning and hopefully start programming it.

As my mind always does, I am already wondering to start thinking about an RS232 to I2c board. Anybody want in on getting something together?

[mackrackit]

As my mind always does, I am already wondering to start thinking about an RS232 to I2c board. Anybody want in on getting something together?

Might be an interesting project, but I have not used a bootloader yet of any kind.

[cncmachineguy]

Well even if it weren't a bootloader, it seems like it could have value as an interface. Yet anoyher way to talk to the animals.

[mackrackit]

Just a thought.

Have a PIC receive data from the PC serially and squirt the same data out I2C ???
That would be too easy.

[cncmachineguy]

I soldered all the smt parts on my card, uP,3311,12 volt driver, and LED's. and of course the ICSP header. Wrote a quik ASM to just turn the LED's on and off and LED's all work! This is a major milestone for me, this is my first dive into SMT.

Next up on the list, do the same thing using PBP. Of coursethis means figuring out how to pull everything together, IDE, compiling and of course setup stuff for the chip. WOW what an exciting new road I am traveling on today!!

Of course I have to post this kind of thing here, cuz you guys are the only folks I know that can appreciate these small feats.

[mackrackit]

Of course I have to post this kind of thing here, cuz you guys are the only folks I know that can appreciate these small feats.

I know what you mean.

The first time I did a blinky with a PIC it was around the holidays. I called my wife over and excitedly showed her the LED turning on and off. She looks at it for a bit, walks over to the tree, plugs it in, waits for the lights to start blinking, turns to me and says, "SO". She then leaves the room.

[cncmachineguy]

more progress, but a little confusion.

Worked through all the issues of getting everything to work together. Compiled and programmed the blink program that pops up in the MCS program. Mind you I am using MPLAB. Well heres my confusion: with the pauses left at 500, it takes about 5 sec to blink. If I change it to 50, seems about 1/2 sec as the program says it should. Now there are no config,define's, or whatnot, Any thoughts on this?

[mackrackit]

What are you using for an oscillator? Type and speed.

The default configs in the PBP directory *.inc file has the OSC set for HS.
And PBP defaults to 4MHz.

If you have an external OSC add
DEFINE OSC x
x being speed.

[cncmachineguy]

I think I just found the problem. I left too much up for granted. Being new to this chip, I never dreamed it would default to a 500K clock!

BTW, I am running intosc (apperantly at 500K, not 4M like I assumed) So I will set osccon to be 4M and see what happens

EDIT: How fantastic life is when you tend to the little things. now works as it should. Off to do more fun stuff

[cncmachineguy]

New question
Heres a snipit:

' Configure pins for digital operation (uncomment as needed).
' These settings are intended as simple examples.  For more detail,
' see the appropriate device datasheet for register descriptions.
'ANSEL =  %00000000  ' 16F88, 16F688, 16F690, 16F88x
'ANSELH = %00000000  ' 16F690, 16F88x
'ADCON1 = %00000111  ' 16F87x, 16F87xA, 18F452
'ADCON1 = %00001111  ' 18F4620

Why when I uncomment the ANSELH line, I get a syntax error for that line? How should I be setting it?

[cncmachineguy]

Well I don't get it, but after changing nothing, it works. go figure

[mackrackit]

Looks like, but I have not used this chip, that the ANSEL has changed some.
ANSELA
ANSELE
ANSELF
ANSELG

ANSELA = %00000000
ANSELE = %00000000
ANSELF = %00000000
ANSELG = %00000000

Maybe...

[cncmachineguy]

Well I broke my own rule of troubleshooting- NEVER change more then 1 thing at a time!! While I was trying to figure it out, I must have kept changing "define osc 4" to "define osc = 4". Playing with caps back and forth. I was relocating where I had the statement and not noticing I kept adding the = sign.

[cncmachineguy]

new question, or looking for suggestions.
I am gonna run my pic at max speed for it. thats 32 meg. The way I was going to handle my step/dir signals was to just pass them through to my drives. So my main would look something like this:

Main
 portc = porta ' pass all values to C
 if porte!=0 then LimitHit 'check for overtravels
 goto main

Thats my whole main section. Now for my problem

If I want my interface card to look and act like a Gecko drive, their timing is this: step signal requires a min low of .5microsec and a high of 4 microsec. It occurs to me the .5uS will be 4 instructions running at 32meg so I think I could miss that pulse real easy. In fact I may miss many.

Now there are some other thing going on here, 1 I don't think EMC is updating the port that fast, and 2 I can make the pulses longer. The one thing I can't do is IOC cuz the boards made already so wrong port.

I guess I am just looking for other opinions here as to how to handle this. BTW, If i hit a limit, I don't care if I miss steps at that point.

[mackrackit]

If it is any help..
My setup has the step drive set to 5000 ns. "nano"

[cncmachineguy]

5000nS = 5uS, yes? thats 40 instructions instead of 4! so as long as I am checking within 2uS, or 20 instructions, I won't miss it. in fact, maybe I should just check the limits in the main, then have an interupt every 1 or 2 uS to shift the ports. then I know I won't miss any.

Thoughts?

[mackrackit]

Maybe run the latency test on EMC2 and then run the conf wizard to see what your target PC will need/do exactly.

I am only running one parallel port on a 1.3 GHz machine with 758 MB ram. Two ports may make a difference.

Those be my thoughts.

[cncmachineguy]

I am blessed with 4 8-bit timers to go with my 16 bit timer. along with some DT_INT, I should be able to make this work just wonderful!!

And that is a great idea Dave, I never really considered running 2 ports may slow things down a bit.

[cncmachineguy]

So far I have a main that just moves porta to latc on every iteration. It also checks that enable is high. If enable is low, it gosubs to disable drives, and waits there for a high again on the enable line. At which point it returns to the main to keeep passing values from porta to latc.
Also have a DT_INT every 5 mS. this does nothing but inc a counter used to flash a LED every .5 sec. That is also handled in the main. If count=100 then toggle LED

This all works

Now its time to step up the function here. I want to move the port passing to the int. But I am having a brain fart about the timming. The pulses last for 10uS high and 10uS low. I am thinking a 5uS interupt will ensure I NEVER miss a pulse, but my mind is cloudy on this. My int will be ASM, so no PBP context saving for entry and exit. I want to do this so I can do more stuff and never worry about missing a step.

Does this seem right?

[ScaleRobotics]

Now its time to step up the function here. I want to move the port passing to the int. But I am having a brain fart about the timming. The pulses last for 10uS high and 10uS low. I am thinking a 5uS interupt will ensure I NEVER miss a pulse, but my mind is cloudy on this. My int will be ASM, so no PBP context saving for entry and exit. I want to do this so I can do more stuff and never worry about missing a step.

You could do an interrupt on change of state for portA,

RAC_INT -- RA Port Change

Then have your interrupt routine look to see which bit has changed state.
</pre>

[cncmachineguy]

Don't I need to do that on a port with IOC? Port B seems to be my IOC port, but since B has ICSP pins, I left them dedicated to ICSP. I need all 8 pins for my control.

[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]

So far I have a main that just moves porta to latc on every iteration.

Hey Bert,

I am trying to understand this better. Would you mind generalizing what it is your board is going to be doing? I take it that it is passing all of the data from porta to portc. But beyond that, I am in the dark. I guess your EMC2 program is sending stepper motor signals through the parallel port, to your board. Then your board is passing it to the stepper if it is enabled. Couldn't you just avoid passing it from one port to another, and act directly on the parallel port pins, or am I missing something?

[cncmachineguy]

Walter you are exactly right. I could have just passed the signals to the drives. In fact I thought about doing just that. But heres the thinking:
This will be a project to be done in several phases.
phase 1:
pass motor signals to the drives
watch limits and disable drives if hit
report to EMC a problem has occured
LED indicators for drive status (enabled or disabled)
phase 1 will give me basic functions of my machine while playing with future phases.

phase2:
add in serial comm and set some parameters such as drive current, switch offsets, and any others I can think of. My machine has mill and hotwire capabilities all built in, I am sure There will be different "Zeros" for each. I am not sure EMC can handle that. So I may have to have my board maintain an offset and get a signal from EMC to tell it which mode its in. That way The board could adjust the axis when "tool change" occurs. for this I will need to talk to the steppers.
Until Phase 2 is complete, the offset stuff will be handled in the machine program.

phase3:
Turn the card into a full controller, being able to download a G-code program to it and hit go, elimiting the need for EMC at all.
This will be a big deal and prolly take a good while.


Happy to answer any more questions, just ask.

[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!