Starting PIC24HJ128GP202 [SOLVED]

[ING.remco]

Hello,

I'm trying to program the PIC24HJ128GP202 with compiler version 5.007 for a simple blinking led function to confirm if the code and MCU works. For the clock I will be using the internal clock.

The code is as following:

[temtronic]

have you set the 'build configuration' in MPLAB to 'release' instead of 'debug' ?

jay

[ING.remco]

I'm write the program in CCS C compiler and program the MCU with the dedicated tool for pickit 2. So there is no MPLAB involved.

[Ttelmah]

You have got a current limiting resistor to the LED?.
I've seen people have this sort of behaviour where there is not a suitable resistor, and the chip overloads when the LED goes on.
Does your 'Ecap' have the low ESR required. It really wants to be a SMD cap _very_ close to the pins....
Other comment what other smoothing is present?.
Look at figure 2.1 in the data sheet. The 0.1uF ceramic capacitors are required, and should be as close as practical to the pins.

[ING.remco]

Yup there is a current limiting resistor that does not allow any current higher than 5 mA (that's what the pin maximum can handle). Even tested it only with an oscilloscope, but that didn't help either.
And I also placed the decoupling capacitors, but it didn't helped. Theoretically it would work without the decoupling capacitor only it would not be optimum.
No other smoothing is present, but places some for a test but didn't helped either.

[wangine]

Check very carefuly the AVdd and VCap/Vddcore respectively 7 and 17. I don't remember wich one needs just a capacitor, no VDD, just read datasheet about those pins. I just search now pdf. It's the Vcap/vddcore, page 15 on table 1-1. Also more is explained on page 16, 2.3 cap. I remember i put a smd ceramic cap to be very close on pins.
Here is my config, should work on most 24F family.

[ING.remco]

I have rebuild the whole setup and added all the decoupling capacitor. And in addition added some capacitors on the power supply line (more than enough). Also replaced the 4.7 uF for a 10 uF (atm no low ESR possible). And included all the #fuses that wangine had provided. But still no improvements. I really don't get it anymore. Is it really that hard MCU to get running?

[Eugeneo]

I remember having some issues with the clock speed on this pic. I know this works so hopefully it helps.

[ING.remco]

Thank you all for the comments. But I found the problem. It was just a F****** freshman mistake. NEVER EVER TRUST A BREADBOARD. I thought it would be easy to test it fast with a breadboard but of course that was the problem. Rebuild on something different and it WORKS. Afterhand I also tested if the decoupling capacitors were needed. But after removing them all the setup still functioned. And the capacitor for the Vcap could also be a normal Elco with no special ESR rating. So about that was I right.

Just thank you for your patience, and this could be closed.

[Ttelmah]

However you _will_ find that once the chip starts operating other components connected to it, the reliability shoots down, if the decoupling is less than needed.....

I've often pointed out in the past that it is worth taking a look at a PC motherboard. Dozens of really high quality capacitors round the supply connections, and then ceramic capacitors next to just about every chip. Now manufacturers do not spend money pointlessly, so they know that these parts are needed.

[asmallri]

[ING.remco]

There is no arguing in that. But the implementation of decoupling capacitors is to reduce the noise on the power supply going into the mcu. Therefore all measurement will be the "same".
On larger PCB's the generation of the different kinds of power rails is mostly on the edge and far away from the important IC's. Along the way all kind of noise will be picked up on the power lines and eventually come to the IC's. There the implement decoupling capacitor.
But if you have only one mcu and the power supply is almost on top of the mcu and if you go really far and place it in a metal box. There will be almost no noise than that is generated by the MCU and power regulation. And if the power regulation is also very stable and within the specs of the mcu a decoupling capacitor will not be that very useful for a test.

And this MCU is a good example. They RECOMMEND decoupling but the Vcap is REQUIRED. In other words you need minimum the Vcap to let the MCU work. But to improve we have some additional notes.

But of course when I design PCB's with all kinds off recommendation provided by the manufacturers, they will be implemented. Worst case is that you need them, best case you can leave them out (if that is possible).

[newguy]

There's good practice and there's practice that "gets you by". Endeavour to hold yourself to good design practices and you'll be able to sleep at night because of the confidence you'll have in your design(s). Do enough to get by, and you're going to have a short career. ....And little sleep just prior to leaving the profession.

[gaugeguy]

ING.remco,
I have to disagree with you.
The primary purpose of the decoupling capacitors is not to reduce noise but to provide a low inductance current supply to the IC. This low inductance current supply is needed to provide the extremely short inrush of current required as digital gates switch states. Without this present, and depending on how many gates end up simultaneously switching state, the IC can experience a momentary, local brownout. All traces and all leads have inductance that increase with length. The only way for a decoupling capacitor to provide the low inductance current supply is to be physically close to the IC supply pins.
Ignore at your own peril...

[Ttelmah]

Hurrah!.

and (of course) as soon as a processor starts to do more work (either just calculating, or - worse - switching more external lines), the local changes in demand can 'shoot up'.....