Datasheet

Chapter 3 Port Integration Module (PIM9E128V1)
MC9S12E128 Data Sheet, Rev. 1.07
Freescale Semiconductor 161
3.4.6 Polarity Select Register
The Polarity Select Register selects either a pull-up or pull-down device if enabled. The pull device
becomes active only if the pin is used as an input or as a wired-or output.
3.4.7 Pin Configuration Summary
The following table summarizes the effect of various configuration in the Data Direction (DDR),
Input/Output (I/O), reduced drive (RDR), Pull Enable (PE), Pull Select (PS) and Interrupt Enable (IE)
register bits. The PS configuration bit is used for two purposes:
1. Configure the sensitive interrupt edge (rising or falling), if interrupt is enabled.
2. Select either a pull-up or pull-down device if PE is set to “1”.
Table 3-36. Pin Configuration Summary
DDR IO RDR PE PS IE
1
1
Applicable only on Port AD.
Function
2
2
Digital outputs are disabled and digital input logic is forced to “1” when an analog module associated with the port is enabled.
Pull Device Interrupt
0 X X 0 X 0 Input Disabled Disabled
0 X X 1 0 0 Input Pull Up Disabled
0 X X 1 1 0 Input Pull Down Disabled
0 X X 0 0 1 Input Disabled Falling Edge
0 X X 0 1 1 Input Disabled Rising Edge
0 X X 1 0 1 Input Pull Up Falling Edge
0 X X 1 1 1 Input Pull Down Rising Edge
1 0 0 X X 0 Output to 0, Full Drive Disabled Disabled
1 1 0 X X 0 Output to 1, Full Drive Disabled Disabled
1 0 1 X X 0 Output to 0, Reduced Drive Disabled Disabled
1 1 1 X X 0 Output to 1, Reduced Drive Disabled Disabled
1 0 0 X 0 1 Output to 0, Full Drive Disabled Falling Edge
1 1 0 X 1 1 Output to 1, Full Drive Disabled Rising Edge
1 0 1 X 0 1 Output to 0, Reduced Drive Disabled Falling Edge
1 1 1 X 1 1 Output to 1, Reduced Drive Disabled Rising Edge