On Mon, Apr 29, 2013 at 02:59:29PM +0100, emacstheviking wrote:
I have built a library for using the Hexwax expandIO-USB chip and I have now got some code to drive a stepper motor:
doOption :: HWHandle -> Flag -> IO () doOption dev (Backward n) = do putStrLn $ "> STEP BACKWARD " ++ (show n) let x = [ stepBit b | b <- [3..0]] return () where stepBit p b = setBit p b 0 >> setBit p b 1 where setBit p b s = HW.setPortBit dev p b s >> stepDelay
The other posted solutions are good, but I also want to make a very important comment about the above code: it does not actually step any bits! All it does is print some stuff. x is simply a name for a list of IO actions; it is never used so it just gets garbage collected and the IO actions are never run. -Brent