18F2550 and Blink Led

[n0yox]

I was not aware of the 18F25K22. I should have asked for advice before I made the change. Sometimes selecting a new device can be very confusing. I will look at the data sheet for the 18F25K22 , do you have any other suggestions for a 16f648a substitute with more memory. I don’t really need the extra I/O’s just more code space.
Thank you very much!

[Dave]

If you are looking for a direct replacement I would suggest the 16F1847. Faster and twice the memory.

[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.