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
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.
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.
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 ??
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?.
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.