NXP Semiconductors MPC5644A Reference Manual page 896

Enhanced Time Processing Unit (eTPU2)
Field
12 Insert Physical Tooth
IPH This bit generates a dummy physical tooth which has the same effect as a real physical tooth, and resets
itself subsequently. If EAC is in Halt mode, it switches back to Normal mode
it switches to High Rate Mode. If Angle Logic is frozen by HOLD = 1 (see below), it returns to the state it
was at the freezing moment.
No Operation.
Insert dummy physical tooth.
IPH reads as 1 in the next microinstruction after it is asserted, negating subsequently. However, it can be
set twice in two consecutive microinstructions to generate two teeth and make the EAC go from Halt to
Normal to High Rate Mode.
13-14 Missing Tooth Counter
MISSCNT Decremented on each estimated tooth, stops at zero. Used for generation of "Dummy Tooth" whenever it
holds a non-zero value.
00No missing tooth
01One missing tooth
10Two missing teeth
11Three missing teeth
If the tooth is detected or inserted before the missing tooth tick count completes (going High Rate mode,
see Section 24.5.7.5.3, High rate mode
count continues in High Rate mode (see
15 Last Tooth Indication
LAST Asserted by microcode and negated when a tooth is detected or inserted via IPH.
Not Last Tooth.
Last Tooth - reset TCR2 Counter at the end of the tooth tick count (after physical tooth or IPH = 1) when
MISSCNT = 0.
If the tooth is detected or inserted before the tooth tick count completes (going High Rate mode, see
Section 24.5.7.5.3, High rate mode
the tooth count completes and MISSCNT = 0
1
Missing a physical tooth naturally causes EAC to get into Halt mode.
24.5.7.2.2 TCR2 – Timer Counter 2
In Angle Mode TCR2 counts angle ticks instead of time.
896
(Acceleration)), MISSCNT resets immediately, but missing teeth
Section 24.5.7.12.1, TPR
(Acceleration)), LAST resets immediately, but TCR2 resets only when
MPC5644A Microcontroller Reference Manual, Rev. 6
Description
buffering).
1
. If EAC is in Normal Mode,
Freescale Semiconductor