At 05:44 PM 4/29/2012, Spehro Pefhany wrote: >Internal brownout can't be guaranteed to not reset the part below 2.11V >on the LF32x. (between 1.80 and 2.11V with nominal at 1.90V. Thanks for that clarification. OK - that means that I can't use=20 brown-out reset at all. However, I *thought* that I had the config=20 word set up to disable the BOR module. >If you have "noise" on the power supply, for example, from operating >an intermittent load such as a beeper, motor, solenoid, pulsed LED=20 >or some such load, >then if that noise causes the power supply voltage to drop below=20 >1.90 V (nominally) >for more than a microsecond or thereabouts, then the chip will go=20 >into reset and not >begin to operate again until 1.925 to 1.95V, the way I read the data=20 >sheet. Worst-case it might not come out of BOR until 2.16V. Maybe=20 >it goes back into reset then if the load starts again. > >Does that sound like a possibility? Have you put a decent (>=3D50MHz bandw= idth) >scope on the power supply rails _right_ at the MCU GND/VDD pins? Yeah - I had a 200MHz DSO right at the power pins. That helped me=20 fix one problem I was having (my bench supply going into current=20 limit for a couple of microseconds when the PIC went to turn on one=20 of those monstrously-high inrush-current LM2623 DC-DC converters I=20 talked about a few weeks ago). I fixed that by momentarily=20 connecting some nice, stiff NiMh cells in parallel with the power=20 supply during the DC-DC converter startup. For tracking down this problem, I simply disconnected the enable=20 lines to the DC-DC converters (they have pull-up and pull-down=20 resistors so as to float safely) but was still observing this=20 problem. There was no other load on the power supply except for the=20 PIC chip itself, which wasn't driving any outputs. I mentioned that I had previously tried adding "_LPBOR_OFF" to the=20 config word without having any effect other than increasing current=20 while the PIC was supposedly in sleep. Unfortunately, I could find=20 no description of what the LPBOR module was or how it was supposed to=20 work in the datasheet, so I removed "_LPBOR_OFF" from the config=20 word. What I don't remember is whether that was when I was using the=20 beta version of the AC244045 Debug Adapter or whether it was with the=20 chip all by itself. Anyway, I opened a support ticket with Microchip. The first=20 suggestion they gave was to add that "_LPBOR_OFF" bit back into the=20 config word. This time, it appeared to fix my problem. I'm working with the PIC=20 all by itself at this point and indeed: dropping the supply voltage=20 down to below 2.0V resulted in the chip NOT going into reset - the=20 output pins remained as low-impedance. I didn't go much below 2.0V=20 since I don't expect to be working at that low of a supply voltage. So: I look to be OK at this point. I did have problems with the beta=20 version of the debug adapter not working at less than about 2.5Vdc=20 but I'm attributing that to the beta nature of the adapter. I see=20 that production versions of the adapter are now available, so I'll=20 order some of those for future work with the 10F32x family. But the=20 LF322 does indeed work down to less than 2.0Vdc. I appreciate the suggestions that were made. Many thanks! dwayne --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .