SC9S12XS256J1MAA FREESCALE [Freescale Semiconductor, Inc], SC9S12XS256J1MAA Datasheet - Page 484

• Manufacturer Part Number: SC9S12XS256J1MAA
• Description: HCS12 Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Timer Module (TIM16B8CV2) Block Description
16.4.3.1
Internal register whose output drives OCx can be programmed before timer drives OCx. The desired state
can be programmed to this Internal register by writing a one to CFORCx bit with TIOSx, OCPDx and TEN
bits set to one. Setting OCPDx to zero allows Interal register to drive the programmed state to OCx. This
allows a glitch free switch over of port from general purpose I/O to timer output once the OCPDx bit is set
to zero.
16.4.4
The pulse accumulator (PACNT) is a 16-bit counter that can operate in two modes:
Event counter mode — Counting edges of selected polarity on the pulse accumulator input pin, PAI.
Gated time accumulation mode — Counting pulses from a divide-by-64 clock. The PAMOD bit selects the
mode of operation.
The minimum pulse width for the PAI input is greater than two bus clocks.
16.4.5
Clearing the PAMOD bit configures the PACNT for event counter operation. An active edge on the IOC7
pin increments the pulse accumulator counter. The PEDGE bit selects falling edges or rising edges to
increment the count.
The Pulse Accumulator counter register reflect the number of active input edges on the PACNT input pin
since the last reset.
The PAOVF bit is set when the accumulator rolls over from 0xFFFF to 0x0000. The pulse accumulator
overflow interrupt enable bit, PAOVI, enables the PAOVF flag to generate interrupt requests.
16.4.6
Setting the PAMOD bit configures the pulse accumulator for gated time accumulation operation. An active
level on the PACNT input pin enables a divided-by-64 clock to drive the pulse accumulator. The PEDGE
bit selects low levels or high levels to enable the divided-by-64 clock.
The trailing edge of the active level at the IOC7 pin sets the PAIF. The PAI bit enables the PAIF flag to
generate interrupt requests.
484
Pulse Accumulator
Event Counter Mode
Gated Time Accumulation Mode
OC Channel Initialization
The PACNT input and timer channel 7 use the same pin IOC7. To use the
IOC7, disconnect it from the output logic by clearing the channel 7 output
mode and output level bits, OM7 and OL7. Also clear the channel 7 output
compare 7 mask bit, OC7M7.
The pulse accumulator counter can operate in event counter mode even
when the timer enable bit, TEN, is clear.
S12XS Family Reference Manual, Rev. 1.09
NOTE
NOTE
Freescale Semiconductor