mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 484

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

Timer/PWM Module (TPMV3)
21.3.5
These read/write registers contain the captured TPM counter value of the input capture function or the
output compare value for the output compare or PWM functions. The channel registers are cleared by
reset.
21-12
Reset
CPWMS
ELSnB
ELSnA
MSnA
Field
3–2
W
4
X
0
1
R
Mode select A for TPM channel n. When CPWMS and MSnB are cleared, the MSnA bit configures TPM channel
n for input capture mode or output compare mode. Refer to
controls.
Note: If the associated port pin is not stable for at least two bus clock cycles before changing to input capture
Edge/level select bits. Depending upon the operating mode for the timer channel as set by CPWMS:MSnB:MSnA
and shown in
the level that is driven in response to an output compare match, or select the polarity of the PWM output.
If ELSnB and ELSnA bits are cleared, the channel pin is not controlled by TPM. This configuration can be used
by software compare only, because it does not require the use of a pin for the channel.
TPM Channel Value Registers (TPMxCnVH:TPMxCnVL)
0
7
MSnB:MSnA
mode, it is possible to get an unexpected indication of an edge trigger.
XX
XX
1X
00
01
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
Figure 21-12. TPM Channel Value Register High (TPMxCnVH)
Table
0
6
Table 21-5. TPMxCnSC Field Descriptions (continued)
21-6, these bits select the polarity of the input edge that triggers an input capture event, select
ELSnB:ELSnA
Table 21-6. Mode, Edge, and Level Selection
X1
X1
00
01
10
11
00
01
10
11
10
10
5
0
Output compare
Center-aligned
Pin is not controlled by TPM. It is reverted to general purpose I/O or
Input capture
Edge-aligned
Mode
TPMxCnV[15:8]
0
PWM
PWM
4
Description
Table 21-6
Low-true pulses (set output on channel match when
0
3
High-true pulses (clear output on channel match)
High-true pulses (clear output on channel match
Low-true pulses (set output on channel match)
other peripheral control
when TPM counter is counting up)
Toggle output on channel match
Capture on rising or falling edge
Clear output on channel match
for a summary of channel mode and setup
Set output on channel match
TPM counter is counting up)
Capture on falling edge only
Capture on rising edge only
Software compare only
0
2
Configuration
Freescale Semiconductor
0
1
0
0