AVR-Chat

>>> wbounce@safeplace.net 26/11/2004 2:39:20 pm >>>
>I agree with the CLEAN 5V but you do not need 2 sources. You can use
the
>same source for motor and MCU. You need to put a separate voltage
>regulator on the MCU circuit from the motor circuit with caps going
from
>the input to ground and from the output to ground. 
>Also an important consideration is the type of voltage regulator you
are
>using. If it is a 7805 you need something like 1.5 volts above the
>output which over 6.5 volts. This means you can not use 4 AA
batteries.
>Six AA 1.5 V batteries will give you plenty of room but 6 AA
>rechargeables only have 1.2V which is still borderline.

In this situation you would use a low-dropout version of the 7805 as
standard practice.
What out though, LDO regs are unstable, they must be bypassed
properly.

Dave :)