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Timer Interface Module (TIM)
Technical Data
MC68H(R)C908JL3E/JK3E/JK1E
—
Rev. 2.0
140
Timer Interface Module (TIM)
MOTOROLA
When ELSxB:ELSxA = 0:0, this read/write bit selects the initial output
level of the TCHx pin. (See
Table 10-3
.) Reset clears the MSxA bit.
1 = Initial output level low
0 = Initial output level high
NOTE:
Before changing a channel function by writing to the MSxB or MSxA bit,
set the TSTOP and TRST bits in the TIM status and control register
(TSC).
ELSxB and ELSxA — Edge/Level Select Bits
When channel x is an input capture channel, these read/write bits
control the active edge-sensing logic on channel x.
When channel x is an output compare channel, ELSxB and ELSxA
control the channel x output behavior when an output compare
occurs.
When ELSxB and ELSxA are both clear, channel x is not connected
to an I/O port, and pin TCHx is available as a general-purpose I/O pin.
Table 10-3
shows how ELSxB and ELSxA work. Reset clears the
ELSxB and ELSxA bits.
Table 10-3. Mode, Edge, and Level Selection
MSxB
MSxA
ELSxB
ELSxA
Mode
Configuration
X
0
0
0
Output
Preset
Pin under Port Control;
Initial Output Level High
X
1
0
0
Pin under Port Control;
Initial Output Level Low
0
0
0
1
Input
Capture
Capture on Rising Edge Only
0
0
1
0
Capture on Falling Edge Only
0
0
1
1
Capture on Rising or Falling Edge
0
1
0
1
Output
Compare
or PWM
Toggle Output on Compare
0
1
1
0
Clear Output on Compare
0
1
1
1
Set Output on Compare
1
X
0
1
Buffered
Output
Compare or
Buffered
PWM
Toggle Output on Compare
1
X
1
0
Clear Output on Compare
1
X
1
1
Set Output on Compare