EasyPIC-6 Development Board by MikroElectronica - Take"2"

[cidrontmg]

Hi, finally got my EasyPic6 yesterday. Not all of the stuff I ordered, but at least the main board. Rest coming later (hopefully). Tried compiling some (Basic) code, and got it to do funny flashing LEDs, and text on the COG2x16 display. This is a neat thing. Reminds me strongly of the first computer I built, many years ago. S-100 bus, Z-80 CPU, 2 boards of 8k of static RAM, a cassette tape for mass storage, and a B/W TV, where I fed the output directly to the cathode. No keyboard, just toggle switches on the front panel.... And an enormous amount of ICīs on the boards (all TTL logic). Powered with an old IBM transformer, also would be good for spot welding. And two Mallory 25000 mF (not micro-F, - thatīs really 25 Farads...) caps... Admittedly, EasyPic6  is a bit more sophisticated. Thereīs a learning curve looming ahead, I hope itīs not a vertical wall when I hit it.
 

[Bluechip]

Hi Olli

Doubt if they're really 25 farad ... On some German PSU's I worked on some caps were marked as 68,000 mF.

However, in The Parts Listing they were described as 68mF, and on the wiring diagram as 68,000uF.

I've no idea why they should be so marked, 'cos it's not correct. But not unknown.

Cannot imagine why anyone would want a cap. of that size for ripple rejection?

Tried a search on the type number, probably on it?

Dave BC

[DMIOM]

...... On some German PSU's I worked on some caps were marked as 68,000 mF

Possibly that'll be the difference is symbology - the Brit . for decimal and comma for thousands - versus the continental European use of the comma for decimal separator?

Dave

[cidrontmg]

Hi Bluechip, I canīt be sure they really were 25F, I had no way of testing/measuring them. But Iīm fairly sure they were. They came from a scrapyard (as did the transformer), and they looked more like car batteries than ("normal") electrolytes. In a rectangular plastic case (there was metal underneath, but not exposed). And with copper screw-on terminals instead of the leaden studs. And nowhere near as heavy as batteries. Quite huge things. I donīt think they ever were in a (mainframe) computer PSU, or even near a computer (or a PSU of any sort), but they came cheap (same as any ali scrap), and had all the capacitance I could ever wish for. 25000 mF, 25 volts.
Theyīre not with me any more, a friend was building a capacitor discharge welder, and he talked me into giving them away for that project. I donīt know how successful the project turned out, but if not, it certainly was not because of too small caps.
BTW. The same scrapyard had lots and lots (several hundred, I imagine, in a huge pile) of keyboards, which were practically unobtainable elsewhere then (1977-78). But he couldnīt sell them, he had a list from IBM about what bits he could sell, and what not, that really had to be crushed and scrapped. And no matter how nicely I tried to convince him of letting me have one, no way. Same thing with ribbon (flat) cables. Not one meter could I pry off him.
 
 

[Bluechip]

Dave

I'm aware of the , / . thing. They were in fact 68,000 uF. We had to change a good few. Why? Because they were rated at 40VDC Wkg. Fine. Except the off-load DC volts of that PSU @ 240VAC input was >51V. Not much 'Vorsprung Durch Technik' about those then  .... The Spec called for 63VDC Wkg. so how someone thought 40VDC was OK is anyones guess. Entertaining bang when they let go anyway .. 

Olli

Only said it was unlikely, not impossible .. 

If they were as big as a car battery, it may be that's what they were. I worked for IBM for 16 years. Biggest I ever saw on a CPU , IIRC, was 250,000 uF @ 7.5 VDC. There were 6 in parallel on a 2.18V (?) PSU fitted to the System 7 CPU. About 70mm dia. x 150mm . May well have been larger caps. on machines I had no dealings with.

The narkiest ( not IBM ) was 2200uF @12kV. Like a young Wheelie Bin. Off some sort of Radar transmitter IIRC. Not the sort of thing to discharge with a screwdriver ..

IBM were/are very sensitive about spare parts going walkies. I think they don't want them to go to third party maintainers .. Naturally ..

If they were the transparent ribbon cables, they have a fair bit of silver in them ... IIRC.

Off to my freezing shop ... finish sorting out the screw junk pile ... I can feel the excitement and enthusiasm building up now ... NOT

Dave BC

[buffalow bill]

Hi everybody, how are things progressing. Would you still recommend the EasyPIC-6 over an Arduino?

Bill

[raynerd]

Hi Bill

I recently purchased 12 Arduino boards for use as a class electronics/programming "club" at school. They are cheap, infact on ebay I paid Ģ35 each for board, LCD display, nearly 100 components (LEDS, resistors, IR sensor, IR remote...), 100 connection wires, USB lead and a little box to put it all in! Sketch, the compiler is a free download for the full version and there is so much on the net already developed for arduino that within 2 minutes I was off and running with sample code, 20 minutes up and running with simple codes I`d written and after an hour, I was doing some persistence of vision stuff that was way above my head but I just copied the code and circuit diagram off the net!

All that said, I`m currently working on a clock timing machine to time my new clock when it is setup. I couldn`t do it with the Arduino board as it didn`t give me the functionality needed and more than that, after using the EasyPIC6 on this project for the last few weeks it really is a dream to use and in my opinion well worth every penny.

My humble opinion - if you want to "play" at it, for Ģ35 you just can`t beat the arduino but the EasyPIC6 really is a fantastic piece of pro kit and gives you the flexibility and speed to write and edit code very quickly, without the faff of breadboard circuits!

I know there are a few on here which are much better at coding than me and I`m sure they will give you there more experience opinion! 

[dickda1]

How did I miss this thread till now!

I own an EasyPIC5 and BigPIC5.  Used both in an engineering course I used to teach about 5 years ago.

Mikroelectronica stuff is simply the best.  Inputs and outputs from the PIC processor are nicely provided.  I use their pascal compiler.  Microdevices has nice boards, but not nearly as good as these.  If you feel compelled to learn assembler, these Mikro boards are the place to do it.

Bought both directly Belgrade because it was much cheaper than I could get from the east coast here in the States.  Don't know how they manage to sell stuff so cheaply.  Always thought it was ironic to buy something from a city only about 10 years after it was being bombed by NATO.

-Dick

[soli20]

could any one help me in my project

[dickda1]

Soli20,

What family of processor are you intending to use?  

While there are knowledgeable electronics guys on this site, you might be better off asking on a micro forum.  Check out links on this page:
http://www.eng-tips.com/viewthread.cfm?qid=219971&page=2
-Dick

[raynerd]

could any one help me in my project

What actually is your project??????? 

[Bluechip]

could any one help me in my project

What actually is your project??????? 

According to his other post, he's doing a robot .. narrows it down a bit ... maybe...

BC

[John Rudd]

could any one help me in my project

I already posted in his other thread asking what experience he had et-al.....

Maybe I missed his reply?

What actually is your project??????? 

[matnewsholme]

My humble opinion - if you want to "play" at it, for Ģ35 you just can`t beat the arduino but the EasyPIC6 really is a fantastic piece of pro kit and gives you the flexibility and speed to write and edit code very quickly, without the faff of breadboard circuits!

I know there are a few on here which are much better at coding than me and I`m sure they will give you there more experience opinion! 

Chris

do you think the power feed you did last year could be implemented on an arduino board? been playing with arduino for a few weeks and want to do something similar to what you did.

Mat

[raynerd]

Mat, The power feed could definately be done on the arduino, infact, Kwackers who visits here, the chap that made the rotary table divider code, has been working on a 3 axis power feed for the arduino. In other words, a three axis controller!!

I`m only playing with arduino at a very basic level and I must admit I`m quite a bit better with the Mikro stuff despite them apparently being similar! I guess if your use to coding, the syntax is the same but when your not really use to it, the difference between the two is vast in my opinion!
The basics of the code I used was to have a pulse in an interrupt.

void interrupt(){
if (modeRun = 1)   //do we want to move the motor
PORTA.b1 = 1; // pin high to the stepper controller
delay   // have a v short delay
PORTA.b1 = 0; // pin low


Then I had it so that in the main code something like:

if (goButton)         // if we press the go/start button
modeRun = !modeRun    // flip modeRun on and off - i.e press button, motor runs and again it stops.

if (directionButton)   // if we press the direction button
PORTA.b2 = !PORTA.b2  //direction flips between on and off, left and right



---------

I literally had something like that wrote down for my first code. Infact, I bet you could do with without the interrupt just to test it:

main code {
if (goButton)         // if we press the go/start button
modeRun = !modeRun    // flip modeRun on and off - i.e press button, motor runs and again it stops.

if (directionButton)   // if we press the direction button
PORTA.b2 = !PORTA.b2  //direction flips between on and off, left and right

while (modeRun)    //when modeRun is on
{
PORTA.b1 = 1; // pin high to the stepper controller
delay   // have a v short delay
PORTA.b1 = 0; // pin low
}

Then just hook it up and see!

[matnewsholme]

cheers Chris

finally got round to mounting stepper on x-axis on my X3 as first stage of cnc conversion. initially just want to use it as powerfeed so arduino linked to stepper driver seems way to go. want to use a pot for speed selection so modifying one of sample arduino sketchs as a quick and dirt proof of concept. If I feel brave I might try and convert your code across to arduino (not sure how it handles interrupts yet - more reading needed  )

Mat

[kwackers]

Hi Mat,

I'm part way through doing something similar to what you suggest, but sadly it's a 'stalled' project due to a complete lack of time at the moment...

If it's any help this code sets up two lots of interrupts, a mpg (int on pin change) and a timer. Here's the code for them both.

Steve.

Code: [Select]

 

const int MPGALine = 20;
const int MPGBLine = 21;

int AState = 0;            // mpg vars
int BState = 0;


// timer interrupt handler
ISR(TIMER2_OVF_vect)
{
  // some code
}


void setup()
{
  // init timer interrupts
  // timer2 settings: Prescaler / 256, WGM mode 0
  TCCR2A = 0;
  TCCR2B = 1 << CS22 | 1 << CS21;

  // timer2 Overflow Interrupt Enable
  TIMSK2 = 1 << TOIE2;

  // reset timer
  TCNT2 = 0;

  // setup the MPG interrupts

  pinMode(MPGALine, INPUT); // int 3
  attachInterrupt(3, mpgAChange, CHANGE);

  pinMode(MPGBLine, INPUT); // int 2
  attachInterrupt(2, mpgBChange, CHANGE);
}


//-----------------
// mpg interrupt handler

void mpgAChange()
{
  AState = digitalRead(MPGALine);
  if (AState != BState)
    CurrentPosition += MPGMultiplier;
  else
    CurrentPosition -= MPGMultiplier;
}

void mpgBChange()
{
  BState = digitalRead(MPGBLine);
  if (BState == AState)
    CurrentPosition += MPGMultiplier;
  else
    CurrentPosition -=  MPGMultiplier;
}



[dickda1]

If using an Easydriver or Pololu stepper driver or even a simple H-bridge be careful to watch the current draw.  A small/medium stepper motor like an M23 is right at the upper limit for these popular microprocessor-powered drivers - even with a good heat sink and a fan.

I built a stepper motor controlled laser for a DAVID 3D laserscanner.  The duty cycle was low so that the driver could cool down.

-Dick

[matnewsholme]

Kwackers

cheers for the interrupt code. will give it a try when I get that far.

dickda1

not going to drive stepper directly from arduino board. using arduino to generate step/direction signals for a proper stepper driver.

Mat

[dickda1]

Mathewsholme,

I didn't state it well.  The arduino board can't usually source enough current to drive anything but a very small stepper.  That includes the plugin motor driver boards.

Keep us informed as your project progress.  I am interested.

Dick