Enabling/Disabling UART in Code

[jecottrell]

Hello All,

I need to drive a 3.3V part with a 5V PIC (18F2525). So I'll have the UART on the 18F2525 driving a 3.3V part. I can either use a level shifter or a voltage divider. I haven't been able to find a level shifter that meets my needs: 3 High to low and 2 low to high drivers, SOIC part, shutdown, etc.... So I've resigned myself to voltage dividing. So that leads me to a couple of questions (all of which are driven by the need for low power).

1. Does the UART TX line idle low or high?

2. If it idles high, can I disable it in code to eliminate the drain through the voltage divider?

3. Does anyone have a better way to do this or know of good level shifter that is readily available (Digikey, Mouser, Newark)?

Thanks,

John

[PCM programmer]

http://www.ccsinfo.com/forum/viewtopic.php?t=25437&highlight=disable+uart