Communication Processor Module
16-8
MPC823e REFERENCE MANUAL
MOTOROLA
RISC
COMMUNICATION
16
PROCESSOR MODULE
TIME—Timer Enable
This bit controls whether the microcontroller’s internal timer can send a tick to the
microcontroller based on the value programmed into the TIMEP field.
0 = Stop RISC timer table scanning.
1 = Start RISC timer table scanning.
Bits 1, 16–23 and 25–31—Reserved
These bits are reserved and must be set to 0.
TIMEP—Timer Period
This field controls the microcontroller’s timer tick. The RISC timer tables are scanned on
each timer tick and the input to the timer tick generator is the general system clock divided
by 1,024. The formula is (TIMEP + 1)
×
1,024 = (general system clock period). Thus, a value
of 0 stored in these bits gives a timer tick of 1
×
(1,024) = 1,024 general system clocks and
a value of 63 (decimal) gives a timer tick of 64
×
(1,024) = 65,536 general system clocks.
DR2M—IDMA Request 2 Mode
This bit controls the IDMA request 1 (DREQ2
) sensitivity mode.
0 = DREQ2
is edge-sensitive.
1 = DREQ2
is level-sensitive.
DR1M—IDMA Request 1 Mode
This bit controls the IDMA request 0 (DREQ1
) sensitivity mode.
0 = DREQ1
is edge-sensitive.
1 = DREQ1
is level-sensitive.
DRQP—IDMA Emulation Request Priority
This field controls the priority of the external request signals that relate to the serial
channels. Refer to
Section 16.2.3 Communication Between the Microcontroller and
Peripherals
for more information.
00 = IDMA requests have priority over the serial communication controllers and USB
(default).
01 = IDMA requests have priority immediatley following the serial communication
controllers (option 2).
10 = IDMA requests have the lowest priority (option 3).
11 = Reserved.
EIE—External Interrupt Enable
Configure this bit as instructed in the download process of a Motorola-supplied RAM
microcode package. This bit is also used by IDMA channel 1 to enable single-buffer mode,
as described in
Section 16.6.3.11.4 Single-Buffer Burst Fly-By Mode
.
0 = DREQ1
pin cannot interrupt the microcontroller.
1 = DREQ1
pin can interrupt the microcontroller.
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