July 24, 2024, 05:58:36 AM

PIC-P26J50 power

Started by AlainBlaster, June 16, 2014, 07:02:09 AM

Previous topic - Next topic


I have a pair of PIC-P26J50 with MOD-MRF89-915 plugged in to UEXT.

When I program and run the MiWi P2P Node1 (coordinator) demo code using PICKit3 and run it via the PICKit it works.
I can see it send three broadcast packets using XENA packet sniffer on channel 24.

After FLASHING when I run the board using just a USB cable and no PICKit3 attached it does not work.

The USB power LED is on.
The USB power jumper is shorted (factory default).
I read 3.27 V on the supply pins.
The Node1 code does not turn on LED_1 like it does via PICKit.
I see no packet activity on XENA even after manual resets.

Why is this? Is the board not getting reset properly when not attached to a PICKit?
Manual reset does not solve the problem either.

Before I start probing around with an oscilloscope...
...I am asking first in case this issue has been seen by others.

I see the same kind of behavior (not working) with the end node code Node2.
I have not tried running it through the PICKit3 yet.

If these boards do not work without PICKit's (highly unusual) I'd be out of luck for I do not have two PICKits! What is going on with this board?

Surely this board has been tested running just off a USB cable to provide power?
So it does not make sense, it should work off USB power and or external 3.3 V power (I don't have one to try).

Any ideas?


Hey AlainBlaster,

3.27 V is a bit lower than the usual 3.30V.

PIC-P26J50 should work off the USB. I recommend you to test and see what happens if you first power the board and then connect the module. I'd also test with another USB port and possibly and another cable - sometimes these might limit the maximum current. Avoid using USB hubs or splitters.

Best regards,
Technical support and documentation manager at Olimex


Are you sure you compiled a 'release' version for use without the Pickit3?
If you left the 'DEBUG = ON' config parameter at ON, then it won't work without Pickit3.
Otherwise you should be fine.