NXP Semiconductors MPC5644A, Reference Manual, Page: 957 / 1735

Enhanced Time Processing Unit (eTPU2)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor 957
24.5.9.6.3 ERTA/B as ALU destination and ERWA/B
The value in ERTA and ERTB registers can be written in match registers of the selected channel by using
fields ERWA and ERWB (
Section 24.5.9.3.5, Write Channel Match and UDCM Registers ). If, at the same
microinstruction, ERTA or ERTB is the destination of an ALU/MDU microoperation, the value written in
the Match registers is the ALU/MDU result.
The same applies to UDCM when ERTA is the destination of an ALU operation and instruction fields
ERWA and CMW are active.
If an ALU operation occurs in parallel with ERWA/B but ERTA/B are not the destination of an ALU/MDU
operation, then UDCM and MatchA/B receives the ERTA/B value.
24.5.9.6.4 ERWA/B and MRLE
ERWA/B automatically sets the MRLEA/B channel latch, respectively (see Section 24.5.9.3.5, Write
Channel Match and UDCM Registers ). Microinstruction fields ERWA/B independently sets MRLEA/B
channel flags, regardless of MRLE.
24.5.9.6.5 CHAN assignment, Read Match and ERWA/B
When CHAN is a destination of an ALU operation it causes a read of the CaptureA/B register values into
ERTA/B. The Capture registers loaded into ERTA/B are selected by the new CHAN value. The value of
the CaptureA/B registers overwrites any read-match commanded simultaneously.
If CHAN assignment happens with an ERWA/B operation in the same instruction, the updated Match
register(s) belong to the new selected channel.
24.5.9.6.6 Read Match and ERWA/B
If a read match operation is executed with ERWA/B in the same microinstruction, the MatchA/B registers
receive the old values of ERTA/B, and the ERTA/B registers receive the old MatchA/B values
simultaneously, i.e.: ERTA/B and MatchA/B swap their values.
If ERTA/B is the destination of an ALU operation at the same instruction, MatchA/B gets the ALU result
(see
Section 24.5.9.6.3, ERTA/B as ALU destination and ERWA/B ), but the ERTA/B not being written still
receives the old MatchA/B values.
yes yes SPRAM read data
(post-inc, pre-dec and ALU result
ignored)
no yes ALU result
(post-inc an pre-dec ignored)
Table 24-117. DIOB load from SPRAM and ALU
DIOB selected as
SPRAM read destination?
DIOB selected as
ALU destination?
DIOB load value