mc9s08qd4 Freescale Semiconductor, Inc, mc9s08qd4 Datasheet - Page 154

• Manufacturer Part Number: mc9s08qd4
• Description: Hcs08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Timer/Pulse-Width Modulator (S08TPMV2)
If the associated port pin is not stable for at least two bus clock cycles before changing to input capture
mode, it is possible to get an unexpected indication of an edge trigger. Typically, a program would clear
status flags after changing channel configuration bits and before enabling channel interrupts or using the
status flags to avoid any unexpected behavior.
11.3.5
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 value registers are cleared
by reset.
In input capture mode, reading either byte (TPMxCnVH or TPMxCnVL) latches the contents of both bytes
into a buffer where they remain latched until the other byte is read. This latching mechanism also resets
(becomes unlatched) when the TPMxCnSC register is written.
154
CPWMS
Reset
Reset
X
0
1
W
W
R
R
Bit 15
Timer Channel Value Registers (TPMxCnVH:TPMxCnVL)
Bit 7
0
0
7
7
MSnB:MSnA
XX
XX
1X
00
01
Figure 11-10. Timer Channel Value Register Low (TPMxCnVL)
Figure 11-9. Timer Channel Value Register High (TPMxCnVH)
14
0
6
0
6
6
ELSnB:ELSnA
Table 11-5. Mode, Edge, and Level Selection
MC9S08QD4 Series MCU Data Sheet, Rev. 3
X1
X1
00
01
10
11
00
01
10
11
10
10
13
0
5
0
5
5
Pin not used for TPM channel; use as an external clock for the TPM or
revert to general-purpose I/O
Center-aligned
Edge-aligned
Input capture
compare
12
Output
Mode
PWM
PWM
0
4
0
4
4
Capture on rising edge only
Capture on falling edge only
Capture on rising or falling edge
Software compare only
Toggle output on compare
Clear output on compare
Set output on compare
High-true pulses (clear output on compare)
Low-true pulses (set output on compare)
High-true pulses (clear output on compare-up)
Low-true pulses (set output on compare-up)
11
3
0
3
3
0
10
0
2
0
2
2
Configuration
Freescale Semiconductor
9
0
1
0
1
1
Bit 8
Bit 0
0
0
0
0