mcf51jf128 Freescale Semiconductor, Inc, mcf51jf128 Datasheet - Page 837

• Manufacturer Part Number: mcf51jf128
• Description: Mcf51jf128 Reference Manual
• Manufacturer: Freescale Semiconductor, Inc

37.4 Functional Description
The following sections describe the FTM features.
The notation used in this document to represent the counters and the generation of the
signals is shown in the following figure.
Freescale Semiconductor, Inc.
QUADMODE
QUADEN
PHBPOL
QUADIR
TOFDIR
Field
4
3
2
1
0
Phase B Input Polarity
Selects the polarity for the quadrature decoder phase B input.
0
1
Quadrature Decoder Mode
Selects the encoding mode used in the quadrature decoder mode.
0
1
FTM Counter Direction in Quadrature Decoder Mode
Indicates the counting direction and it is updated according to selected encoding mode.
0
1
Timer Overflow Direction in Quadrature Decoder Mode
Indicates if the TOF bit was set on the top or the bottom of counting.
0
1
Quadrature Decoder Mode Enable
Enables the quadrature decoder mode. In this mode, the phase A and B input signals control the FTM
counter direction. The quadrature decoder mode has precedence over the other modes. (See the table
Mode, Edge, and Level Selection in the description of the CnSC register.)
This field is write protected. It can be written only when MODE[WPDIS] = 1.
0
1
Normal polarity. Phase B input signal is not inverted in FTM.
Inverted polarity. Phase B input signal is inverted in FTM.
Phase A and phase B encoding mode.
Count and direction encoding mode.
Counting direction is decreasing. FTM counter decrement.
Counting direction is increasing. FTM counter increment.
TOF bit was set on the bottom of counting. There was an FTM counter decrement and FTM counter
changes from its minimum value to its maximum value.
TOF bit was set on the top of counting. There was an FTM counter increment and FTM counter
changes from its maximum value to its minimum value.
Quadrature decoder mode is disabled.
Quadrature decoder mode is enabled.
FTMx_QDCTRL field descriptions (continued)
MCF51JF128 Reference Manual, Rev. 2, 03/2011
Preliminary
Description
Chapter 37 FlexTimer (FTM)
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