Hi, can anyone think of any reason why my olimex icd2 works when i connect to the 40pin dip version of the 18f4550, but not the smt 44-tqfp version?

I have a professionally manufactured 18f test board with a 44 pin smt pic on it, but the icd2 wont connect. MPLAB allways says that wrong target ID is connected.

I have tested and retested the ICSP connections, all are fine.

Any ideas?

Many thanks.
Chris.

 

Do you have a schematic or part # of the target board?

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com

 

Hi bill,

Ive got a schem of my board, but not the of the other one.

This is my first go at smt pics, its not going well!

Ive basically just soldered on the pic and a ICSP header, and soldered on the (bottom pcb side) blue jumper wires.

This is allways the first thing i do when i make a new board. If the ICSP doesnt work, then somethings not right.

MPLAB doesnt recognise my board, or the other pro. one. If i connect up a previous project (uses a 4550 40pin pdip) and i can get the stupid olimex programmer to work, then MPlab connects without problems.

Please tell me im doing something foolish, i just cant work out why it doesnt work.

Ive trashed three 4550's on several copies of my board, i kept thinking that i had ruined the chips through ESD.
Lucky ive got my trusty (if not slightly vulgar) AOYUE rework station.

Anyway ive now come to the conclusion that the chips are ok.

everything in the schem s unconnected, just the pic and the icsp are soldered to the board.


Cheers bill.

Attached Images

	schem1.png (40.0 KB, 17 views)
	board1.png (30.3 KB, 9 views)

 

I think the 44pin device have dedicated ICD pins, take a look at the datasheet and search for ICD.

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com

 

yeah i noticed that,
I cont checked the pro board and found that it was wired up to the multiplexed pins though.

Ill whip up another basic board, that simply has 2 headers and a 4550. Ill connect one header up to the dedicated and the other, the multiplexed pins.

I hope this works.
thanks mate.

 

How did you fix your ICD2?

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com

 

i didnt, it still wont enter debug mode, and it sometimes wont program succesfully.

Still waiting on my student loan, to buy parts.

icd2 will work with every board i have tried, apart from these smt ones.

 

Hi Herbert
Did you notice the schematic and Layout, at pins 28 and 29. I fear, Vdd is shown connected to Gnd and Vss to 5V as per the schematic? It should be otherwise I feel. Same is the case with pins 6 & 7. please check .
This will sort it out.

__________________
Regards,
Sarma.

 

Hi Chris,
Plz check whether u hav connected the Vcc of ur target board & the pin No. 2 of RJ11 from ICD2 r shorted.
Regards,
Renjith..!

 

Well spotted Sarma.

Mike.

 

Sarma your a genious!

I was just about to give up hope.

Reputation++.

thanks very much.

 

Just tried it, it works!

Once again, nice one sarma

 

This doesnt explain why the Professional board doesnt work, but i really dont care as long as my boards work.

Does anyone know if the dedicated ICSP port has to be turned on before use (i.e config bits)?
If it does, it strikes me as slightly foolish, having to config the pic using legacy ports first.

 

Happy that the Chip is ALIVE with all the trouble it had with reverse polarity. Thanks for the compliment-- there is nothing about it. i looked at it with open mind and with no prior bias in my mind while looking at the problem.
You are lucky that the chip is working.
Thanks again

__________________
Regards,
Sarma.

 

thats the good thing about these forums. I tend to have a fairly closed mind when it comes to problems with my own boards.

I have probably ruined about 4 chips in total, whilst removing them from the board. Not to worry though, it works now.

cheers mate