MPC563XM Reference Manual, Rev. 1
866
Freescale Semiconductor
Preliminary—Subject to Change Without Notice
when immediately after the detection of this extreme acceleration, the following tooth indicates extreme
deceleration back to the original RPM.
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.
23.4.7.10 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 23.4.7.5.3, “High Rate Mode (Acceleration)
) used to set the TDL1 flag on single transition modes,
and TDL2 on double transition modes (see signals TSE1,TSE2 in
). The same applies when
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: TDL1 asserted on single transition
modes, TDL2 asserted on double transition modes.
•
on mode m2_st: the window opens on Match1 (which enables Transition1) and does not close with
Match2. If Match2 comes before Match1, it blocks Match1 and, hence, Transition1.
•
on mode m2_o_st: the window opens on Match 1 (which enables Transition1) and closes on
Match2. Match2 is enabled by Match1, 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 Transition1, which is enabled by Match1. The window does
not close with Match2, but if it comes before Match1 the later gets blocked and, hence, blocks
Transitions. Match1 is also a condition for the window, so the microcode closes it by clearing
MRL1.
•
on mode m2_o_dt: the window opens on Transition1, which is enabled by Match1. The window
closes on Match2, which is enabled by Match1. Match1 is also a condition for the window, so the
microcode closes it by clearing MRL1.
•
on all other Double Transition modes, the window opens on Transition 1.
23.4.7.11 Restarting Angle Logic
It is not advisable to toggle the ETPUTBCR 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 ETPUTBCR 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.