SX52 gets REALLY hot.
spooky
Posts: 2
Hi, long-time SX user, first-time posting. [noparse]:)[/noparse]· Thanks to parallax for hosting this page.
Anyway, I am using an SX52 on a pcb i had made from expresspcb.com.· I have used the design before and things worked fine.· Last night I populated a new board (essentially just a 5V regulator, blocking cap, and sx52).· I "ohmed" out important pins with respect to each other to make sure nothing was shorted and all seemed fine.· Then I powered it up and it got REALLY hot.· I disconnected it and rechecked the device for shorts...· nothing.· (i did the soldering under a 40x scope.· All the pins matched up with the pads and I tried to wiggle each pin with tweezers to make sure it was a good solder joint.)
Anyway, I powered it up again and I can do a Run->Device->Read and it seems to read the contents of FLASH (whatever was left in there from shipping).· I can do a Run->Device->Verify and the bar fills up and then it says something like "Verify failed at oscillator" or "Verify failed at E2FLASH..."...· ????· If I try to program, it just says "Programming failed".
I tested the SX-Key with another board with the same exact circuit layout and the SXkey programmed it fine.
Did I nuke the chip somehow?· Has anyone seen this before?· I have on occaision seen the chip heat up a lot, but after I program and let it run it's ok...· What could I be doing???
ah, i did realize that I have MCLR *directly* connected to +5V, without a resistor.· That's probably not great design practice, but I assumed MCLR to be high impedance????
Anyway, I am using an SX52 on a pcb i had made from expresspcb.com.· I have used the design before and things worked fine.· Last night I populated a new board (essentially just a 5V regulator, blocking cap, and sx52).· I "ohmed" out important pins with respect to each other to make sure nothing was shorted and all seemed fine.· Then I powered it up and it got REALLY hot.· I disconnected it and rechecked the device for shorts...· nothing.· (i did the soldering under a 40x scope.· All the pins matched up with the pads and I tried to wiggle each pin with tweezers to make sure it was a good solder joint.)
Anyway, I powered it up again and I can do a Run->Device->Read and it seems to read the contents of FLASH (whatever was left in there from shipping).· I can do a Run->Device->Verify and the bar fills up and then it says something like "Verify failed at oscillator" or "Verify failed at E2FLASH..."...· ????· If I try to program, it just says "Programming failed".
I tested the SX-Key with another board with the same exact circuit layout and the SXkey programmed it fine.
Did I nuke the chip somehow?· Has anyone seen this before?· I have on occaision seen the chip heat up a lot, but after I program and let it run it's ok...· What could I be doing???
ah, i did realize that I have MCLR *directly* connected to +5V, without a resistor.· That's probably not great design practice, but I assumed MCLR to be high impedance????