Trouble starting PIC or internal clock on 12f683?
I am using the program from Walter Dunckel (http://www.scalerobotics.com/stamps/...ssthrough.html). It is unchanged from what's on the web. The PIC doesn't start or the internal clock isn't running. I read the application note on troubleshooting power-up problems, but it still fails. Here is the situation and what I have tried.
Chip is 12f682, tried two of them.
Power is 5.19 VDC
2200uf cap across +5 and GND where it enters the breadboard (tried it without that too)
1uf cap across pins 1 & 8
Power up is via switch so the rise time of +5 is fast and without much ring.
Checked the wiring a half dozen times.
Originally, the input across the 3 diodes was falling at a long slope so I added a pull-down resistor. Now the receiver pulses look like what Walter shows on his o'scope.
Tried it with and without a pull-up resistor on pin 4, mclr
With the given _INTRC_OSC_NOCLKOUT , it never starts, but if I change it to _INTOSCIO I can get it to start very very occasionally.
By "not starting" I mean there are no output pulses to the servos. All output pins are just low.
Any thoughts on what else I can check?
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