MPC555
/
MPC556
SIGNAL DESCRIPTIONS
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
2-45
Figure 2-12 Type G Interface
2.5.5 Five-Volt Input/Output Pad
This pad type is for 5-V bi-directional pins. There is provision to pull the pin up to 5 V
and logic to control when the pull-up is enabled. For a 5-V driver, the internal “Fast
Mode” signal selects the slow or fast driver. All 5-V inputs have hyteresis.
2.5.5.1 Type H Interface
This pad has logic for a 3-V output function as well as a 5-V input-output function. A
“3-V / 5-V sel” interface signal determines which driver gets selected.
This pad type has two separate data output paths. These paths are multiplexed onto
the output pin based on the 3-V / 5-V select signal. This pad also has a dedicated syn-
chronous input path.
If only one of the output paths is used on a device, the other can be connected to
ground. In this case, the 3-V / 5-V select signal must be tied to the appropriate value
to disable the other path.
Data Out
Pin
OE
IE
3 V
Data In
Drive Sel
Sprds
Driver
Receiver
Logic
3-V
3-V
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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