Thanks, but I meant the other way around. The 3.3REG is powering the PIC also Pickit3 as required

PICkit is powered fom USB

 

hi C,
Is this track path an option.?
E

Hi E,
Yes it used to be there before I moved the Pickit3 socket over to fit the 100nF Cap
I'll add a link, thanks.
C

PICkit is powered fom USB

Hi T,
Yes it is, but it also needs an external supply too. If, as you say only the PIC is being programmed, then it would program ok, without the external supply.
Cheers, C.

 

hi C,
Is this track path an option.?
E

Hi E,
Yes it used to be there before I moved the Pickit3 socket over to fit the 100nF Cap
I'll add a link, thanks.
C

PICkit is powered fom USB

Hi T,
Yes it is, but it also needs an external supply. If, as you say only the PIC is being programmed, then it would program ok, without the external supply.
Cheers, C.

 

Hi,
The 18F4431 side is programmed and the LEDs are flashing
C

 

Hi,
Added the 18LF4620 and now it gets hot
I'll re-check everything and try again.
C

 

Hi,
16LF4620
I found one of the PORT PINs was grounded , I removed the fault.

While the PIN-GND was there, the VDD/VSS PINS got hot, now it is removed the resistance between VDD and GND is APP 25ohms, (too low) and they still get hot. Could the GND cause a PIC to internally fault?
C

 

You measure 25 ohm between pic18 Vss and Vdd? It is very low resistance for PIC indeed. Are you measured voltages on the pads before installing the MCU?

 

You measure 25 ohm between pic18 Vss and Vdd? It is very low resistance for PIC indeed. Are you measured voltages on the pads before installing the MCU?

Hi T,
Yes, I check every pad for shorting with the next one, also the VSS VDD voltage.
I now have to add another test: each PIN resistance to GND.
C.

 

You measure 25 ohm between pic18 Vss and Vdd? It is very low resistance for PIC indeed. Are you measured voltages on the pads before installing the MCU?

Hi T,
Yes, I check every pad for shorting with the next one, plus it's continuity, also the VSS VDD voltage.
I now have to add another test: each PIN resistance to GND.
C.

 

hi C,
Another method I have used to find a PCB short circuit, is power the 5V or 3.3v [ which ever ] via a
100 ohm resistor, then measure the +V tracking with a DVM,

E.
BTW: when you make a new PCB, check the power rails for shorts or incorrect pathways BEFORE assembling.

 

hi C,
Another method I have used to find a PCB short circuit, is power the 5V or 3.3v [ which ever ] via a
100 ohm resistor, then measure the +V tracking with a DVM,

E.
BTW: when you make a new PCB, check the power rails for shorts or incorrect pathways BEFORE assembling.

Hi E,
I was just thinking, that I would add an LED line onto the '-V' lead of a DCM, with a switch to GND, then when I'm going round the, in this case, 44x PIN PIC, as above, I could also switch, to see if the LED lights.

I'm constantly checking all of the above, but the error was on a VIA, added after the PIC.

I'm going to swap the PIC for another, and try to answer my question.
C.

 

I a

Hi,
16LF4620
I found one of the PORT PINs was grounded , I removed the fault.

While the PIN-GND was there, the VDD/VSS PINS got hot, now it is removed the resistance between VDD and GND is APP 25ohms, (too low) and they still get hot. Could the GND cause a PIC to internally fault?
C

Are all peripherals ( compass, barometer etc.) in use?
Could you measure the current from the battery.

 

hi C,
Another method I have used to find a PCB short circuit, is power the 5V or 3.3v [ which ever ] via a
100 ohm resistor, then measure the +V tracking with a DVM,

E.
BTW: when you make a new PCB, check the power rails for shorts or incorrect pathways BEFORE assembling.

Hi E,
I was just thinking, that I would add an LED line onto the '-V' lead of a DCM, with a switch to GND, then when I'm going round the, in this case, 44x PIN PIC, as above, I could also switch, to see if the LED lights.

I'm constantly checking all of the above, but the error was on a VIA, added after the PIC.

I'm going to swap the PIC for another, and try to answer my question.
C.

 

Hi,
PIC swapped TICK.
DVM tests TICK.
Programmed and flashing LED TICK.

So, to remind me later: If a PIC is shorted, then it may be damaged, so change.


Now to be more adventurous and try SPI between the PICS.
C.

 

I a

Are all peripherals ( compass, barometer etc.) in use?
Could you measure the current from the battery.

Hi J,
I proceed slowly adding things, when bulding, so onle 3x LEDs added so far.
I've popped the DVM mA fuse, but on 10A it shows app 1.5 AMP total.
---------------------------------------------------------------------------
I have a list for each peripheral current, and uncluding 5Xpots and an LCD screen here is my list:
5110 400 uA led 1-2 mA
18lf4620 1mA
18LF4431 1mA
LED X 3 60mA
POT x5 ??
BAROMETER 40 Ua
COMPASS 10mA
C

 

Hi J,
I proceed slowly adding things, when bulding, so onle 3x LEDs added so far.
I've popped the DVM mA fuse, but on 10A it shows app 1.5 AMP total.
---------------------------------------------------------------------------
I have a list for each peripheral current, and uncluding 5Xpots and an LCD screen here is my list:
5110 400 uA led 1-2 mA
18lf4620 1mA
18LF4431 1mA
LED X 3 60mA
POT x5 ??
BAROMETER 40 Ua
COMPASS 10mA
C

1.5A ??

 

Something is shorting power rails, i would expect maximum 100mA current draw.

 

Something is shorting power rails, i would expect maximum 100mA current draw.

Hi J and T,
Is that decimal point relevant

App 100-150mA.

the 4620 LED flashed for a while, then went intermittent. I checked and as I've run out of 18LF4620, I used an 18F4620 NO GOOD!
I've found an old LF version, so I'll swap that and give it another try.
C

 

Hi,
18LF4620 swapped, TICK
Programmed and LED flashing, TICK
I'll leave it running for a while, before a smiley face.
C

 

Hi,
It ran for a few minutes, then the 18LF4620 LED started flickering and stopped. It occasionally starts, then stopps again.????
Voltages are all ok.
C