16F877A system and tachometer (FIS version) on the table

[mazoul72]

If i put transistor directly to FIS without the +12V and 10Kohms resistors , i can have 12V from FIS (low level on PIC pin) and ground when transistor is "excited" .

[aratti]

Your FIS device has internal pullups, so you don't need the external one.

Cheers

Al.

[mazoul72]

Hello,

i have already put OPTION_REG for pull-up resistors on port B but it is strange :

on RB5 , RB7 i have 6.7 Volts and on RB6 i have 4.98V
My voltage regulator provide 5V and 12V on transformator (Stable)
I don't understand why .

i have an ASM routine for UP/DW/Reset detection .
it doesn't work well .

Start:

ASM

loop
BTFSS PORTB.5 ; on saute instruction suivante si B.5 = "1"
BCF PORTC.3 ; on passe C.3 à "0"
BTFSC PORTB.5 ; on saute instruction suivante si B.5 = "0"
BSF PORTC.3 ; on passe C.3 à "1"


BTFSS PORTB.6 ; on saute instruction suivante si B.6 = "1"
BCF PORTC.4 ; on passe C.4 à "0"
BTFSC PORTB.6 ; on saute instruction suivante si B.6 = "0"
BSF PORTC.4 ; on passe C.4 à "1"

;Si aucunes commandes validées alors on continu dans le programme complet
BTFSC PORTB.7 ; on saute instruction suivante si B.7 = 0 (validée)
GoTo loop

ENDASM

mainprog:
action for each command.....on Fis display
....
...
goto Start
END

Regards
Mazoul72

[mazoul72]

I've just seen that TRISB miss for input PORTB

Is this mistake provide bad functionnal reactions ?

OPTION_REG7=0
TRISB = %11100111 (RB5 to RB7-->steering wheel button detection , RB0 to RB2-->radio display input ENA/CLK/DATA) with internal pull-up .