Strange SerOut Problem

[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.

[masosi]

I've tried the circuit with the Crystal (4MHz), everything seems to be the same...

Attached is the circuit diagram, could someone please check it to see what I am doing wrong please???

The LED blinks if the serial port is not connected to the computer.
The LED doesn't blink if the serial port IS connected to the computer, so I'm thinking its a grounding problem. Any suggestions?

This is the code that I am testing with:

PORTA = 0
PORTB = 0
CMCON = 7 'Set 16F628A Comparators off

Include "modedefs.bas"
light var PORTB.0
Low light

Start:
Toggle light
SerOut PORTA.1,N300,["Pulse",10,13]
Pause 100
goto Start

High light
end

[skimask]

I've tried the circuit with the Crystal (4MHz), everything seems to be the same...

Attached is the circuit diagram, could someone please check it to see what I am doing wrong please???

The LED blinks if the serial port is not connected to the computer.
The LED doesn't blink if the serial port IS connected to the computer, so I'm thinking its a grounding problem. Any suggestions?

This is the code that I am testing with:

PORTA = 0
PORTB = 0
CMCON = 7 'Set 16F628A Comparators off

Include "modedefs.bas"
light var PORTB.0
Low light

Start:
Toggle light
SerOut PORTA.1,N300,["Pulse",10,13]
Pause 100
goto Start

High light
end

Ya, there's a few things wrong with that.
Check your little green book...page 131, 136, 139, 144. You might find your problem/answer there.