mc9s12xd256 Freescale Semiconductor, Inc, mc9s12xd256 Datasheet - Page 333

• Manufacturer Part Number: mc9s12xd256
• Description: Hcs12x Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Freescale Semiconductor
.
CLK[1:0]
PAMOD
PEDGE
PAOVI
Field
PAI
3:2
5
4
2
0
Pulse Accumulator Mode — This bit is active only when the Pulse Accumulator A is enabled (PAEN = 1).
0 Event counter mode
1 Gated time accumulation mode
Pulse Accumulator Edge Control — This bit is active only when the Pulse Accumulator A is enabled
(PAEN = 1). Refer to
For PAMOD bit = 0 (event counter mode).
0 Falling edges on PT7 pin cause the count to be incremented
1 Rising edges on PT7 pin cause the count to be incremented
For PAMOD bit = 1 (gated time accumulation mode).
0 PT7 input pin high enables bus clock divided by 64 to Pulse Accumulator and the trailing falling edge on PT7
1 PT7 input pin low enables bus clock divided by 64 to Pulse Accumulator and the trailing rising edge on PT7
If the timer is not active (TEN = 0 in TSCR1), there is no divide-by-64 since the 64 clock is generated by the
timer prescaler.
Clock Select Bits — For the description of PACLK please refer to
If the pulse accumulator is disabled (PAEN = 0), the prescaler clock from the timer is always used as an input
clock to the timer counter. The change from one selected clock to the other happens immediately after these bits
are written. Refer to
Pulse Accumulator A Overflow Interrupt Enable
0 Interrupt inhibited
1 Interrupt requested if PAOVF is set
Pulse Accumulator Input Interrupt Enable
0 Interrupt inhibited
1 Interrupt requested if PAIF is set
sets the PAIF flag.
sets the PAIF flag.
PAMOD
CLK1
0
0
1
1
0
0
1
1
Table 7-18. PACTL Field Descriptions (continued)
Table
Table
PEDGE
CLK0
0
1
0
1
0
1
0
1
7-20.
7-19.
MC9S12XDP512 Data Sheet, Rev. 2.17
Table 7-20. Clock Selection
Falling edge
Rising edge
Divide by 64 clock enabled with pin high level
Divide by 64 clock enabled with pin low level
Use timer prescaler clock as timer counter clock
Use PACLK as input to timer counter clock
Use PACLK/256 as timer counter clock frequency
Use PACLK/65536 as timer counter clock frequency
Table 7-19. Pin Action
Description
Clock Source
Pin Action
Chapter 7 Enhanced Capture Timer (S12ECT16B8CV2)
Figure
7-70.
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