HI!
I tryed  to use in PIC16C621A, RA4 as output, open drain. I put a resistor
to Vcc.
Program is ok, but when the output (in that pin, RA4)fall to any value
<Vdd/2, this output come to zero and stay in zero even the value of the
output return to any value > Vdd/2.
In another words, if the output is high, and I force pin 3 ( RA4 ) with a
jump to zero, when I remove this jump the output stay in zero. Note, by the
program this output is high all the time.
The same test in a PIC16F84 this do not happen (no comparator sets!). The
output come to zero with a jump to zero and return to high when remove this
jump.
I didn't find nothing in data sheet.
My sets:
 banc1                                       ;macro to bank 1
 MOVLW  b'00000010'           ;Place option reg setup into W
 MOVWF  OPTION_REG       ; Set up OPTION register
 MOVLW   b'00000000'          ;Porta B as output
 MOVWF  TRISB
 MOVLW   b'00000011'           ; Coloca em w valor para entrada porta
 MOVWF  TRISA                      ;Porta A como entrada de teclado
 banc0                                        ;macro to bank 0
 MOVLW  0X07                         ;comparator off
 MOVWF  CMCON
 MOVLW  B'10100000'            ; int only to tmr0
 MOVWF  INTCON

VRCON left by default. (b'00000000')
Did I forgot any set?
Thanks.
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