icsp pin programing error in pic24fj128gb204

Aycan · Joined: 02 Apr 2004 Posts: 13 Location: TURKEY

ccs c ver 5.075
mplab-x ver 4.05

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

temtronic · Posted: Wed Jun 27, 2018 6:16 pm

While I don't use that PIC, I found it interesting that while PK3 found the device and erased it it couldn't program it. I'd have thought the hardware was OK (pin #s) as 2 out of 3 operation were sucessful.
Something else then got me thinking, as ICSP and ICD are 2 different concepts. ICSP (In Circuit Serial Programming) is just a way to 'stuff code into a PIC' whereas ICD (In Circuit Debugging) is a complicated 'master' program to allow the programmer a 'line by line' view of a PIC program running.
Then I wonder about the 'chicken and egg' problem where you want the PIC to use an optional set of pins for ICD/ICSP yet you need to program the PIC to tell which pins but the hardware is on the optional pins. All this hopefully is explained in the PIC datasheet. Maybe I'm getting too old for PICs...

Jay

Ttelmah · Joined: 11 Mar 2010 Posts: 19504

Any of the ICSP pairs can actually enter the programming mode. For programming _all_ the sets are permanently active. It is the manipulation of the MCLR line needed that prevents accidental entry to programming mode. Once the chip is in programming mode, for debugging, the debug executive program is loaded into the chip, and it is this that then only uses one pair of the pins to load the rest of the code, and for debugging.

So wrong pair of pins selected, the chip will still accept the initial executive programming and reply to this. However when the debug executive takes over, it'll then fail.

If he is just programming the device, there is no need to select the pin pair involved. If it is failing with a second pair, then look at the wiring (length of connections, capacitance etc..). The ICSP connections can be fussy on the faster PIC's in particular. On a couple of PIC24's I have to use cables that are half the length of the normally supplied ones for ICSP to work....

temtronic · Posted: Thu Jun 28, 2018 4:29 am

Thanks for the explainatin Mr T. !
Things were a lot simpler when PICs had windows on them.

Aycan · Joined: 02 Apr 2004 Posts: 13 Location: TURKEY

Hi everybody.
While i trying to fix problem in yesterday night, i realized pickit3 programmed when i connect oscilloscope probe to mclr pin for observe waveform.
Then i connect two of 0.1uF and 0.01uF additional capacitor to 3.3V power trace. Finally it worked. Thanks all of you for giving a time.
Have a nice days.