MC9S08SH4MPJR datasheet(32/341 Pages) FREESCALE

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Chapter 2 Pins and Connections

MC9S08SH8 MCU Series Data Sheet, Rev. 3

Freescale Semiconductor

When an on-chip peripheral system is controlling a pin, data direction control bits still determine what is

read from port data registers even though the peripheral module controls the pin direction by controlling

the enable for the pin’s output buffer. For information about controlling these pins as general-purpose I/O

pins, see Chapter 6, “Parallel Input/Output Control.”

The MC9S08SH8 devices contain a ganged output drive feature that allows a safe and reliable method of

allowing pins to be tied together externally to produce a higher output current drive. See Section 6.3,

“Ganged Output” for more information for conﬁguring the port pins for ganged output drive.

NOTE

To avoid extra current drain from ﬂoating input pins, the reset initialization

routine in the application program should either enable on-chip pull-up

devices or change the direction of unused pins to outputs so they do not ﬂoat.

When using the 8-pin devices, the user must either enable on-chip pullup

devices or change the direction of non-bonded out port B and port C pins to

outputs so the pins do not ﬂoat.

When using the 16-pin devices, the user must either enable on-chip pullup

devices or change the direction of non-bonded out port C pins to outputs so

the pins do not ﬂoat.

MC9S08SH4MPJR Datasheet(PDF) 32 Page - Freescale Semiconductor, Inc