Effects of Current Draw Using Internal VS External PullUps

[rixtalbert]

I am currently writing a little bot of simple code for a 10F206 Six Pin ver.
I have been studying the DICE routine written and posted by Ms. Melanie Newman.

The program just pulses out random high/low logic to a mosfet.

By setting TRISIO=%11111111
CMCONO=%00000001
Option_REG.5=0
Status_REG=10010000 ' the GPWU and GPPU for pullups.

I noticed that when I was in a closed loop waiting for GPIO.1 to go Low (via switch) that the uA current was about 40 to 60 uA without out and external 10k pullup resistor.
I did not have a Pullup resistor on GPIO.3 (MCLR) either.

I powered down the chip and added pullups to GPIO.1 and GPIO.3 .

The Current now while in the loop looking for a low on GPIO.1 is now 8 to 10.4 uA.

The circuit is on a breadboard and should be away enough from RF.
The circuit does not work reliable if the external pullups (10k) are removed and only using the Weak Pullups.

Any one got a hint were to read more on this.

I am using Pic Basic Pro ver 2.47

Thanks

Rix

[Melanie]

Ms. Melanie Newman is a bit formal Rix... just Melanie is fine here...

Internal Pull-Up's are good for local low-speed switching (such as user pushbuttons).

In the original design, R1/D8 also assisted the pull-up on GP3 but it 'should' work without it... when I have a moment, I'll butcher one of my Dice and check...

Note that your lines...

Option_REG.5=0
Status_REG=10010000

are not valid. OPTION_REG bits 6 and 7 control the Pull-Up's and I believe Status_REG should be just STATUS and the % is missing.