18F2550 and Blink Led

[n0yox]

Thank you, I will make an order on Monday. I should have asked before I started this project.
I have tried to use the pic comparison page with some luck http://www.microchip.com/maps/microcontroller.aspx
Melabs once had a very simple chart that compared many of the most common controller however they deleted that page.

I have one more question about the 18f2550 can anyone tell me how to turn on the weak pullups on the top 4 of PORTB “4-7”.

[n0yox]

Is this close?
INTCON2 = %00000000 ' makes all of portb have WPU ? INTCON2<7> 'page 116
TRISB = %00001111 'B. 0:3 are now outputs WPU is now off?

[tumbleweed]

To enable the pullups on PORTB just clear the RPBU bit in INTCON2 using INTCON2.7 = 0. It's an all or nothing thing on that chip... you can't set them individually.

TRISB = %00001111 'B. 0:3 are now outputs WPU is now off?

The comment doesn't match the setting, but to set PORTB 7:4 to inputs and the others (3:0) to outputs you'd use
TRISB = %11110000

The WPU is only enabled when the pin is set to input mode (TRIS bit = 1). It's disabled when the pin is an output (TRIS bit = 0)

[n0yox]

What I was attempting to say with that comment was that by using TRISB = %00001111 after the line containing INTCON2.7 = 0 you would set the bottom 4 bits to outputs causing those 4 bits to no longer have WPU , Maybe I have this backward and it should be TRISB = %11110000 Is this also wrong? As it turns out I need all 8 ports to have WPU’s so I will not be using that line. However for future use I would like to know the correct usage?
Thank you so much!

[AvionicsMaster1]

Try longer pauses.

[richard]

Is this also wrong?

yes its wrong , if you read the datasheet its wpu for all pins that are inputs or no pins have wpu on that port

Each of the PORTB pins has a weak internal pull-up. A
single control bit can turn on all the pull-ups. This is
performed by clearing bit, RBPU (INTCON2<7>). The
weak pull-up is automatically turned off when the port
pin is configured as an output. The pull-ups are
disabled on a Power-on Reset.

[n0yox]

"The weak pull-up is automatically turned off when the port
pin is configured as an output."

So this means all of the wpu are turned off on portb if any pin is a output on portb? I guess I thought because the data sheet said "The weak pull-up is" not "The weak pull-ups are turned off it meant just that one pin.

Thank you very much for clearing that up.

[richard]

So this means all of the wpu are turned off on portb if any pin is a output on portb?

no it means
if (INTCON2<7>) is set then all portb pull ups are off
if (INTCON2<7>) is clear then all portb pull ups are on and that no pin that is an output can have a pull up

[tumbleweed]

If there's any confusion on how to set the pin direction, I like to think of it this way... the TRIS register is short for TRI-STATE register.
If a pin is tri-state, it's floating, so it must be an input. Setting the TRIS bit = 1 enables the tri-state, so 1=input, 0=output.