Configuration switch to set PORTB as digital in 18F2XXX

[yvesmazzon]

Dear Picster,
I'm battling to get the PORTB as digital only. I'm using a 16F2585 chip. but I'm not getting the weak pull up effectively. I have configured as follow:

Device = 18F2585
Xtal = 20 ' Set Xtal Frequency

Config_Start
OSC = HS
PBADEN = off ' PORTB<4> and PORTB<1:0> Configured as Digital I/O Pins on Reset
WDT = OFF ' HW Disabled - SW Controlled
Config_End

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All_Digital = TRUE
PortB_Pullups = On 'Enable to have port B set with a weak pull up
Am I missing something?
Regards,
Yves

[pic-ignorant]

Have you looked through the datasheet to see what peripherals are on those pins, and checked their default state on POR?

[yvesmazzon]

yes I did over and over, and don't know what else has to be done. On a datasheet it says as follow:

Note: On a Power-on Reset, RB4:RB0 are
configured as analog inputs by default and
read as ‘0’; RB7:RB5 are configured as
digital inputs.
By programming the Configuration bit,
PBADEN (CONFIG3H<1>), RB4:RB0 will
alternatively be configured as digital inputs
on POR.

[captainslarty]

Hi
it looks like you will also need to do a trisb=255
after the portb pullups..
Apart from that, it looks ok at first glance in the ASM.

See example 10.2 in the datasheet under portB settings. As John says, some of the pins are set for other uses - CAN etc.

[yvesmazzon]

Hi Joe,
I have try trisb=255 as you suggested but still not working. The program I wrote is a bit long but worked perfectly with the 16F876A and I decided to upgrade the chip with the 18F2585 for more program and memory space. It seems that the the registry configuration is a mine field with the 18F chips. I'm not too experienced with all the subtility of the register. Something I learn is with Proton the ALL_Digital = true does not applies for PORTB. Am I wrong? Any more idea?
Regards,
Yves
For the small story. My cats was fascinated with you bug logo. I had to push it away before he start scratching my laptop screen. I suppose that was the only interesting thing he could find on the screen, smile.

[captainslarty]

Hi Sir, sorry about the cat attracting bug huha
Again, I have not looked too deeply into this specific chip,
but the asm

PROTON#CODE#START
ORG 0
GOTO PROTON#MAIN#START
ORG 8
PROTON#MAIN#START
CLRF 4088,0
CLRF 4011,0
MOVLB 0
F2_SOF EQU $ ; USB.PRP
F2_EOF EQU $ ; USB.PRP
F1_SOF EQU $ ; USB.BAS
F1_000039 EQU $ ; IN [USB.BAS] ALL_DIGITAL = TRUE
MOVLW 7
MOVWF ADCON1,0
F1_000040 EQU $ ; IN [USB.BAS] PORTB_PULLUPS = ON
BCF INTCON2,7,0

'Seems' to conform ok.
(ALL DIGITAL = TRUE) does not set all pins as you may think (on some devices).. it does though, in this case, appear to set as per datasheet... which is only certain pins on portB.
One thing I would suggest, is to look at ALL config settings, not just a few, in other word make usre you set ALL config fuses.
PortB uses some of the pins for CAN. etc.

If you could mail me your full code, I might be able to look at the code and see if I can help, but as said, I am not familiar with this device at all, purely a quick look at the datasheet and the code / asm.

[yvesmazzon]

Hi Joe,
I gave up so I changed my press button away of B0 - B1 and placed them at B6 - B7 and now I have the internal pull up I wanted,
many thanks for your time.
Regards,
Yves