NXP Semiconductors MPC5644A, Reference Manual, Page: 783 / 1735

Enhanced Time Processing Unit (eTPU2)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor 783
3-4 TCRCF[1:0]—TCRCLK Signal Filter Control
This field controls the TCRCLK digital filter (see Section 24.5.6.5, TCRCLK digital filter ), determining
whether the TCRCLK signal input (after a synchronizer) is filtered with the same filter clock as the channel
input signals (see
Section 24.5.5.6, Enhanced Digital Filter – EDF ) or uses the system clock divided by 2,
and also whether the TCRCLK digital filter works in integrator mode or two sample mode (see
Table 24-15 ).
5-6 AM—Angle Mode Selection
This field enables the Enhanced Angle Counter logic to generate angle information (see Section 24.5.7,
EAC – eTPU angle counter ), and also select the tooth signal input and the channel used to process it, as
shown in Table 24-16 . When EAC is not disabled by AM and neither TCR1 nor TCR2 are STAC Clients,
the EAC (eTPU Angle Clock) hardware provides angle information to the channels using the TCR2 bus.
When AM is reset (non-angle mode), the EAC operation is disabled, and its internal registers can be used
as general purpose. For more information, see
Section 24.5.7, EAC – eTPU angle counter .
If TCR1 or TCR2 is a STAC Bus Client (see Section 24.5.6.3, STAC Interface ), the EAC operation is
forbidden, and if AM is set the Angle Logic does not work properly.
Note: Changing AM may cause spurious transition detections on the channel selected by AM, depending
on the channel mode and state (see
Section 24.5.5.3, Transition Detection and Time Base Capture ).
If AM must be changed with GTBE = 1, the recommended procedure is described in
Section 24.5.7.11, Restarting angle logic .
7-9 Reserved
Table 24-13. ETPU_TBCR field description (continued)
Field Description
Table 24-15. TCRCLK filter clock/mode
TCRCF Filter clock Filter mode
00 system clock divided by 2 two sample
01 filter clock of the channels two sample
10 system clock divided by 2 integrator
11 filter clock of the channels integrator
Table 24-16. AM - angle mode selection
Valu
e
TCR2 value Tooth signal
Tooth
processing
channel
0 0 Timebase (EAC operation disabled) not applicable
0 1
Angle Ticks
TCRCLK input 0
1 0 channel 1 input 1
1 1 channel 2 input 2