Strange SerOut Problem

[masosi]

Try using SEROUT2, with a mode # of 3332 (which is optimal). Then try shifting 3332 up and down a bit and see what happens. Eventually you'll hit on a range of numbers that does seem to work. Take the middle one and use it.

I have tried SerOut2 with the following modes: 3322, 3327, 3332, 3337, 3342 and 3347 (+5 increments).
And then again with the following modes (inverted): 19706, 19711, 19716, 19721, 19726 and 19731.

I would have thought I'd get something on the PC, but still nothing. Is this range too big? or too small? If this doesn't work, the is the resonator really going to fix all this?

[skimask]

I have tried SerOut2 with the following modes: 3322, 3327, 3332, 3337, 3342 and 3347 (+5 increments).
And then again with the following modes (inverted): 19706, 19711, 19716, 19721, 19726 and 19731.

I would have thought I'd get something on the PC, but still nothing. Is this range too big? or too small? If this doesn't work, the is the resonator really going to fix all this?

Probably....but the main thing would be to put some sort of counter on it, 'scope, freq-meter, anything and write a program to see how fast the clock is really going.

Failing that, write a program that counts up in seconds. Let it run for a few hours, compare it with a stopwatch and see how far off it is. Maybe it's actually so far out in the weeds that you can't even get into the ball park.

What happens if you write a program to toggle an LED on and off once per second? Does it actually toggle once per second?

Did you smoke the PC's serial port? Have the right COM1 port selected, etc.?
Simple little things...we all know how it goes...but ya never know..could be something stupid that's tripping you up...

[masosi]

I'll try those ideas soon, thanks.

Another thought...
I'm running the 16F628A at 5.0V DC. After looking at the electrical information, it seems that I should be running it at 3.5V. This would run the internal oscillator at a more precise speed. Is this correct?

Please make sure I'm getting this right.
5V supply... 3.5V drop across the PIC... Voltage drop of 1.5V... PIC runs at 150mA
R = V / I
R = 1.5 / .15
R = 10 ohms (1/4 watt)

[skimask]

I'll try those ideas soon, thanks.
Another thought...
I'm running the 16F628A at 5.0V DC. After looking at the electrical information, it seems that I should be running it at 3.5V. This would run the internal oscillator at a more precise speed. Is this correct?
Please make sure I'm getting this right.
5V supply... 3.5V drop across the PIC... Voltage drop of 1.5V... PIC runs at 150mA
R = V / I
R = 1.5 / .15
R = 10 ohms (1/4 watt)

What electrical information is telling you to run it at 3.5v?
If you're talking about parameter F13, that's for 'jitter' not 'accuracy'.

[masosi]

This graph...
Correct?

[skimask]

This graph...
Correct?

That -1% @ 5v isn't going to kill your serial.
Also, it's say 'TYPICAL'...doesn't really mean 'yours'.

[masosi]

Ah... well thats another desperate idea gone...

I'll try the timing trials.