Enhanced Time Processing Unit (eTPU2)
MPC5644A Microcontroller Reference Manual, Rev. 6
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Freescale Semiconductor
When the microcode detects such a case, the Tooth Counter has been advanced by mistake to the next
tooth. The microcode can set the HOLD bit in the TPR, forcing the EAC to freeze and wait for the next
physical tooth to close the gap. When the next physical tooth arrives, HOLD is automatically negated and
the EAC proceeds from that point to the remaining portion of the tooth period, in the same mode it was
when HOLD bit was asserted.
24.5.7.10 Angle logic and channel modes
The TCRCLK transition detection is qualified by a signal that comes from channel 0 (see
and depends on the particular mode (PDCM) programmed for that channel. This configures a window for
TCRCLK detection for the angle logic which is the same (except on High Rate mode, see
Section 24.5.7.5.3, High rate mode (Acceleration)
) used to set the TDLA flag on single transition modes,
and TDLB on double transition modes (see signals TSE1,TSE2 in
channels 1 or 2 are used to control EAC (see signals TS1, TS2 in
window depends on the channel mode as follows:
•
On all modes, the window closes upon a tooth edge detection: TDLA asserted on single transition
modes, TDLB asserted on double transition modes.
•
On mode m2_st: the window opens on Match A (which enables Transition A) and does not close
with Match B. If Match B comes before Match A, it blocks Match A and, hence, Transition A.
•
On mode m2_o_st: the window opens on Match A (which enables Transition A) and closes on
Match B. Match B is enabled by Match A, so it cannot come before.
•
On all other Single Transition modes, the window is “always open”, independently of matches.
•
On mode m2_dt: the window opens on Transition A, which is enabled by Match A. The window
does not close with Match B, but if it comes before Match A the later gets blocked and, hence,
blocks Transitions. Match A is also a condition for the window, so the microcode closes it by
clearing MRLA.
•
On mode m2_o_dt: the window opens on Transition A, which is enabled by Match A. The window
closes on Match B, which is enabled by Match A. Match A is also a condition for the window, so
the microcode closes it by clearing MRLA.
•
On all other Double Transition modes, the window opens on Transition A.
24.5.7.11 Restarting angle logic
It is not advisable to toggle the ETPU_TBCR bit AM while GTBE = 1. However, if the Angle Logic must
be restarted without interfering with the timebase count running on TCR1, the procedure below must be
followed:
1. Write ETPU_TBCR setting AM = 00 and TCR2CTL = 111 at once. That prevents TCR2 from
incrementing while the Angle logic is disabled. The Angle Logic state-machine resets to Normal
mode and the tick prescaler to the initial count by AM = 00, but not the microengine registers TPR
and TRR.
Summary of Contents for MPC5644A
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Page 24: ...MPC5644A Microcontroller Reference Manual Rev 6 24 Freescale Semiconductor...
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Page 1228: ...Decimation Filter MPC5644A Microcontroller Reference Manual Rev 6 1228 Freescale Semiconductor...
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