NXP Semiconductors MPC5644A Reference Manual page 880

Enhanced Time Processing Unit (eTPU2)
Match A causes the output to be driven high (for simplicity the output and input signals are shown as
positive logic). It also causes a transition A, because IPACA = 100 and the input is still low. Match B
occurs after the expected driver delay, and causes a service request. If the output is shorted, a Transition B
occurs on Match B because IPACB = 100. This will cause the output to go low immediately, because
OPACB = 100.
In the second example, an output pulse is generated from an input transition without microcode
intervention. Match A opens a window for transitions and also enables Match B. A rising edge on input
sets output high. On Match B the window closes, and input signal is checked: if sampled high, the output
resets; otherwise it stays high.
In the third example, a pulse is generated depending on the value sampled on the input signal at a
predetermined time. Match A samples the input signal, causing a Transition. Low level on input sets output
low, otherwise it stays high. Match B sets output high. In both cases a service request is issued (microcode
intervention), at the beginning and at the end of the pulse (Match B), if required (SRI := 0).
When IPAC = 1xx, a match event can cause simultaneously a Match
recognition and a Transition detection. Depending on the Channel Mode,
these Match and Transition may have conflicting effects on other
Transition/Match blocking or enabling. In these cases, blocking always
prevails over enabling, effective on the next microcycle.
880
NOTE
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor