Eduardo Murillo

MC9S12NE64 ATD voltage scaling

Discussion created by Eduardo Murillo on Jun 23, 2008
Latest reply on Jun 23, 2008 by Eduardo Murillo
Hi all,

I'm trying to use the MC9S12NE64 to monitor some batteries' voltages. The thing is, the voltage that I need to measure are either 24 or 48 V. I will monitor the batteries and set some kind of alarm when they reach a determined low voltage. I know that the ATD  input pins have a maximum voltage rating of 3.3 V on this microcontroller. So my problem is that I need to scale the batteries' voltage from the 0 - 24 V (or could also be a range from low voltage to 24V) range to the 0 to 3.3 V range, so I can use the on-board ATD to determine their voltages and don't overload the microcontroller. Can someone point me in the right direction as to what I will need to accomplish this? I'm kinda lost on this. Any help is really appreciated.:smileywink: