I have an Explorer16 and the PIC24FJ256B110 PIM. I have used rafalw's modified 4550 code to make it look like a PICkit 2. FirmwareV2.100.07b.for.Explorer16
I am able to successfully program the PIM. After the firmware is programmed, I have to press "run" and that works okay.
However, I am unable to use the debugger features; if I press "Halt" then MPLAB stops responding. If I hit a breakpoint, the PIM's firmware stops execution but MPLAB doesn't show the breakpoint as being hit. Once either of these conditions occur, if I unplug the USB and plug it back in again, I get Unknown Hardware, which means that the 4550 isn't responding to enumeration requests.
I think I may have narrowed the problem down. One potential issue is that the demo application I was using (Joystick) was setting RA0 and RA1 as outputs. However, these are connected to the 4550's TMS and TCK pins. I was afraid of potential contention on these lines, so I set them as inputs. This did not seem to solve the problem, however it does seem like the intelligent thing to do, so I left that part in.
This next method has managed to solve the problem I was having.
3) RESET! (this is the important part!)
Now I can use debugger features normally.
It stopped working again.
I don't understand. I had this working yesterday.
I can Animate. I can Step. I can Run to Cursor, as long as it doesn't take long for execution go get there. But if I Run, MPLAB locks up after about one second.
I have tried MPLAB 8.53 and 8.31.
Ended up purchasing a PICkit 3. No problems now. on-board PICkit 2 is still good for programming, just not debugging.
post edited by ajs410 - 2011/06/07 09:19:15