| ??? 01/31/05 13:02 Read: times |
#86194 - One small step Responding to: ???'s previous message |
Sun Din said:
I have a parallel pair of 0.1uf caps across the entire 5V input between 5V and Ground.
I did not yet connect them across each IC... To be effective, a bypass capacitor must be placed close the the IC's power pins. Did you look at that animation? Here's the link again: http://www.8052.com/forum/read.phtml?id=85887 Also, look at Michael Karas' link showing capacitor placement: http://www.8052.com/forum/read.phtml?id=85921 the PCB board was already designed and populated by someone else ... Did they include bypass capacitors? If not, you should be extremely worried - if they've missed something so basic, what other noise issues will the design have...?! :-0 Look at that FAQ section - is everything suggested there present in your design? http://www.8052.com/faq.phtml?CATEGORY=11 so I tried to solve the problem on the already built board, without having to design a new one, Quality & reliability need to be designed-in; they cannot be bolted-on after the event! I did however run the PIC cct of the power supply and when my cct stalls the PIC board runs as normal But have you tried the other test: Have you run your board from the "110V switchmode" PSU, but on your bench and away from all other unknowns? |
