m using ICD2 Lotha's clone

Its working with PIC16F877A only at 4MHz

Cannot even connect when I use 20MHz

Is it a limitation of ICD or 16F877A?

How can I debug at 20MHz

the speed is critaical to me

Please help me

 

It isn't a limitation of either. You must have something wrong with your clone. Dry joint, dodgy connection etc.

Mike.

 

clone is working properly I debugged 16F877A and 16F877 at 4MHz. its working perfecly. running sepping breakpoints are working. I got only 4Mhz 16F877 so I do not know weather its running at 20Mhz with 16F877

but not 16F877A is not running at 20MHz not even at 10MHz (I cheked with many cristals) But working perfecly with 4MHz

But I want the speed of 20Mz for 16F877A for debuging

Any solutions guys?


S Dewinda

 

My clone works perfectly on a 16F877A at 20MHz and so it must be something wrong with your clone.

Mike.

 

It could be a problem with your program. Have you configured the PIC correctly? If fosc<= 4 MHz you should select the XT oscillator in the configuration word; if fosc>4 MHz select the HS oscillator.

 

I am using clone with opamp MCLR interface vertion (Lothar's design) are u using it or transistor version? however Ill try to assmble ICD on a good PCB. currently Im using perferated board like Lothar's one.

what type of board you are using?

to my expereince PIC are workig quite ok cristals with out 33pF or 15pF stabilizing caps. are they really effects.

sahan

Sahan

 

So is the clone itself that doesn't work? or - as I understand from your posts - you can't debug a target application?

The firmware for the ICD is specifically written for a 20 MHz crystal. My ICD clone is based on Lothar Stolz's old version (the one with transistors), if it matters.

 

You MUST have the capacitors, it 'may' work without, but often it won't, and it certainly won't be reliable - they are there for a reason - FIT THEM!.

You leave out vitally important parts of the circuit, then wonder why it doesn't work?

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Probably missing decoupling caps too, seems people love to leave em out.

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

 

ICD is working with a 20MHz cristal. its ok. im talking about the target PIC .

The program is ok I tested it with 16F877 (without A) with ICD (old version)

As 16F877 is no longer in production I had to go to 16F877A and ICD2

HS XT issue was also cheked. Previusly I used caps for 4MHz its working even without caps (ok I fixed them again)

is there any different typs of cristals the only way I can check a cristal is to connect it to pic and check weather its running. Should I worry about cristal brands or typs ??

Sahan

 

Leads to the crystal should be as short as possible, as should the leads of the capacitors, and also the decoupling capacitors should be as short as possible and close to the PIC.

I suspect you're probably building this on a breadboard, and fairly messily?.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Make sure you are not trying to use the pins that the ICSP uses. You have to leave RB6 and RB7 alone if you expect debugging to work. Without this things act really WIERD and nothing works quite right

I have run a 16F877A both on a Inchworm+/Unicorn (ICD2) and Junebug (Pickit2) clones.

__________________
August Treubig

AG5AT

 

ICD2 clone is made with 16F877A and 20MHz cristal acording to Lothars design

Please conferm me you have debuged 16F877A with 20MHz target with that ICD.

if so I have made some mistake with my board

 

In that case it's your target chip. I've debugged the 16F877A @ 20MHz no problem.

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

 

In fact, that is the only speed I have run the 16F877A at.

__________________
August Treubig

AG5AT