pic16f628: can't use MCLR pin for I/0!

[ramantas]

I disable MCLR by configuration bits,
__CONFIG _INTRC_OSC_NOCLKOUT & _MCLRE_OFF

then type

movlw 0x07
movwf CMCON
bcf STATUS, RP1
bsf STATUS, RP0
MOVLW 0xff
MOVWF TRISA

but TRISA register is not affected on bit 5, and i can not use PORTA bit 5 for input. Why? Microchip datasheet says that bit 5 supports input, if you disable MCLR. Currently i am working on Mplab IDE 6.30 - the chip has the same problem, or is it a software bug? (i noticed that checking the model pic16f628A does not correct the problem)

 

[Exo]

Seems like your config word isn't assembled right

Try __CONFIG 0x3D18

 

[ramantas]

thanks for the reply, but your hint doesn't seem to solve the problem. Anyways, I am planning to connect a 4*4 keypad matrix and an LCD screen to the PIC, so the number of I/O pins is a bit of an issue. Is there anything else I could try to disable MCLR?

 

[Exo]

Did you already try it for real? or just simulation.
I burnt a 16F628A here to try and read a switch on MCLR and it works...
Maybe a simulator bug

 

[ramantas]

Well, you' ve been a great help Exo! No, i hanen't tried this for real yet (no programmer available at this time). I guess I' ll try it again on the MPLAB 6.32 interim release

 

[justin_sane]

How do you reprogram after MCLR is set to input?

 

[Exo]

By making it 14V pic will go to programmer mode - regardless of how the pin is configured

 

[justin_sane]

I program using LVP.

I guess that is out if you are operating in that mode.