Anbeyon, You have to be very careful using RA4. This one is an "open-drain" output which means you cannot set it high by just setting the port bit. You can fix it by connecting a pull-up resistor (10k is fine) to +5v on this pin. It's the only open-drain output and it catches a lot of folks! Then you will remember it forever.
-Craig
Hi I hoping someone might be able to help me.
>
> I am using a pic16f627a to perform bit banged i2c & update of a video
> on screen display chip. all lines used to do this, 5 in total, are
> on
> port a.
>
>
> OSD Chip select, OSD clk, OSD data are on port a bits 0, 1 & 2
> respectively
> I2C SCL and SDA are on port a, bit 3 and 4 respectively.
>
>
> I have a very wierd problem. If I set or clear bits on bits 0,1 or 2
> something happens and causes an i2c bus collision on the sda line.
> sda, is cleared!!
>
>
> as a consequence my master grinds to a halt
>
>
> I have CMCON reg = 0x07 so all comparators etc.... are disabled.
>
>
> Any one out there experienced anything wierd like this ?
>
>
> any thoughts would be greatly appreciated.
>
>
> Anbeyon
>