Tuesday, 29 March 2016

power - PIC circuit won't stay powered


I've built a simple LED sequencer using PIC 18f4550. Outputs are 10 pins on ports C&D. I have now built (soldered) this circuit 3 times and it still only powers on intermittently. I installed a very low current "power on" LED to help troubleshoot. I notice if I touch the chip or certain areas of the board, the circuit works (& power light on). But it intermittently goes out. Almost like there's a loose connection or some capacitive issue. Circuit works fine when the power light is on. Symptoms are the same whether breadboard or soldered. Ideas?


Thanks




please excuse the crudeness of this drawing.
led sequencer for PIC18f4550



Answer



You probably are missing a pullup on the reset pin (/MCLR)


No comments:

Post a Comment

arduino - Can I use TI's cc2541 BLE as micro controller to perform operations/ processing instead of ATmega328P AU to save cost?

I am using arduino pro mini (which contains Atmega328p AU ) along with cc2541(HM-10) to process and transfer data over BLE to smartphone. I...