Using weak pull-up

[Sharky]

I think that I will stick to my pull up resistors, because I will not take any chances.

I have about 300 pcs. of my application with pull-up resistors in the field and they work just great, but now I have to make some changes on the PCB, and I could use a little more space for an extra molex connector.

Thanks for your inputs

Sharky

[dougsego]

I'm attempting to configure portb.0 and portb.1 on a 16F883 as inputs with weak pull-ups. The register set-up code I'm using is:

ANSELH=%00000000 'portb are all digital
trisb=%00000011 ' portb.0 and portb.1 are inputs
option_reg=%10010111 'Global Pull-up disabled and internal clk
WPUB=%00000011 'Weak pull-up portb.0 and portb.1
portb=%00000011 ' Outputs off, inputs don't care

However, when I measure these nodes with a DVM (input impedance ~ or > 500K), I get 0v instead of the 5v I'm expecting.

Any ideas?

Thanks

[Archangel]

I'm attempting to configure portb.0 and portb.1 on a 16F883 as inputs with weak pull-ups. The register set-up code I'm using is:

ANSELH=%00000000 'portb are all digital
trisb=%00000011 ' portb.0 and portb.1 are inputs
option_reg=%10010111 'Global Pull-up disabled and internal clk
WPUB=%00000011 'Weak pull-up portb.0 and portb.1
portb=%00000011 ' Outputs off, inputs don't care

However, when I measure these nodes with a DVM (input impedance ~ or > 500K), I get 0v instead of the 5v I'm expecting.

Any ideas?

Thanks

Hi Dougsego,
Global pull up cleared means bit 7 should be set to zero: option_reg=%00010111 , see page 77 of the Data sheet:
" 0 = PortB pullups are enabled by individual port LATCH values " .