MPC563XM Reference Manual, Rev. 1
Freescale Semiconductor
913
Preliminary—Subject to Change Without Notice
23.4.9.6.3
ERT1/2 as ALU destination and ERW1/2
The value in ERT1 and ERT2 registers can be written in match registers of the selected channel by using
fields ERW1 and ERW2 (
Section 23.4.9.3.5, “Write Channel Match and UDCM Registers
). If, at the same
microinstruction, ERT1 or ERT2 is destination of an ALU/MDU microoperation, the value written in
Match registers is the ALU/MDU result.
The same applies to UDCM when ERT1 is the destination of an ALU operation and instruction fields
ERW1 and CMW are active.
If an ALU operation occurs in parallel with ERW1/2 but ERT1/2 are not the destination of an ALU/MDU
operation, then UDCM and Match1/2 receives the ERT1/2 value.
23.4.9.6.4
ERW1/2 and MRLE
ERW1/2 automatically sets the MRLE1/2 channel latch, respectively (see
Channel Match and UDCM Registers
). Microinstruction fields ERW1/2 independently sets MRLE1/2
channel flags, regardless of MRLE.
23.4.9.6.5
CHAN assignment, Read Match and ERW1/2
When CHAN is a destination of an ALU operation it causes a read of the Capture1/2 register values into
ERT1/2. The Capture registers loaded into ERT1/2 are selected by the new CHAN value. The value of the
Capture1/2 registers overwrites any read-match commanded simultaneously.
If CHAN assignment happens with an ERW1/2 operation in the same instruction, the updated Match
register(s) belong to the new selected channel.
23.4.9.6.6
Read Match and ERW1/2
If a read match operation is executed with ERW1/2 in the same microinstruction, the Match1/2 registers
receive the old values of ERT1/2, and the ERT1/2 registers receive the old Match1/2 values
simultaneously, i.e.: ERT1/2 and Match1/2 swap their values.
If ERT1/2 is the destination of an ALU operation at the same instruction, Match1/2 gets the ALU result
(see
Section 23.4.9.6.3, “ERT1/2 as ALU destination and ERW1/2
), but the ERT1/2 not being written still
receives the old Match1/2 values.
yes
no
SPRAM read data
(post-inc and pre-dec ignored)
yes
yes
SPRAM read data
(post-inc, pre-dec and ALU result
ignored)
no
yes
ALU result
(post-inc an pre-dec ignored)
Table 23-98. DIOB load from SPRAM and ALU
DIOB selected as
SPRAM read destination?
DIOB selected as
ALU destination?
DIOB load value