On Apr 10, 2006, at 2:48 PM, Ben Warren wrote: > Hello, > > I'm a noobie to this CPU, and am utterly confused with how the bits > are > ordered on the GPIO ports. I imagine it's the same as all Freescale > PPCs, but who knows. Anyway... > > Using an MPC8349MDS eval board, I have one LED to play with. From the > schematic, it's connected to GPIO1[1]. From other processors that > I've > worked with, I would have expected to toggle it with either 0x40000000 > (IBM 405) or 0x00000002 (68360). Nope. To make this bit move, I mess > with bit 0x00000040 in the appropriate DAT register. This leads me to > believe that either the bit ordering is something > like ...89abcdef01234567 (sorry for the confusing notation, but > hopefully it makes sense) or the schematic has a typo. Since I'm > trying > to write a generic GPIO handler, I'd like to have a little > confidence in > my extrapolation from a single point. > > Can anybody shed some light on this?
This is because the Freescale docs are misleading. If you look at the schematic you will see the LED is wired to GPIO1[5] which makes sense for the 0x40 value you have to use. - kumar
