MPC555CME Freescale Semiconductor, MPC555CME Datasheet - Page 600

• Manufacturer Part Number: MPC555CME
• Description: KIT EVALUATION FOR MPC555
• Manufacturer: Freescale Semiconductor
• Type: Microcontrollerr

Specifications of MPC555CME

• Contents: Module Board, Installation Guide, Power Supply, Cable, Software and more
• Processor To Be Evaluated: MPC555
• Data Bus Width: 32 bit
• Interface Type: RS-232
• For Use With/related Products: MPC555
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

16.5.3 Auto Power Save Mode
MPC555
USER’S MANUAL
Auto power save mode enables normal operation with optimized power savings. Once
the auto power save (APS) bit in CANMCR is set, the TouCAN looks for a set of con-
ditions in which there is no need for the clocks to be running. If these conditions are
met, the TouCAN stops its clocks, thus saving power. The following conditions activate
auto power save mode.
While its clocks are stopped, if the TouCAN senses that any one of the aforementioned
conditions is no longer true, it restarts its clocks. The TouCAN then continues to mon-
itor these conditions and stops or restarts its clocks accordingly.
• To take the TouCAN out of low-power stop mode when the self wake mechanism
• The SELFWAKE bit should not be set after the TouCAN has already entered low-
• If both STOP and SELFWAKE are set and a recessive to dominant edge
• To prevent old frames from being sent when the TouCAN awakes from low-power
• If the TouCAN is in debug mode when the STOP bit is set, the TouCAN assumes
• Unlike other modules, the TouCAN does not come out of reset in low-power stop
• If the TouCAN is in low-power stop mode with the self wake mechanism engaged
• No Rx/Tx frame in progress
• No transfer of Rx/Tx frames to and from a serial message buffer, and no Tx frame
• No CPU access to the TouCAN module
• The TouCAN is not in debug mode, low-power stop mode, or the bus off state
/
for the TouCAN to set the STOPACK bit.
is enabled, write to CANMCR with both STOP and SELFWAKE clear, and then
wait for the TouCAN to clear the STOPACK bit.
power stop mode.
immediately occurs on the CAN bus, the TouCAN may never set the STOPACK
bit, and the STOP bit will be cleared.
stop mode via the self wake mechanism, disable all transmit sources, including
transmit buffers configured for remote request responses, before placing the Tou-
CAN in low-power stop mode.
that debug mode should be exited. As a result, it tries to synchronize with the CAN
bus, and only then does it await the conditions required for entry into low-power
stop mode.
mode. The basic TouCAN initialization procedure should be executed before
placing the module in low-power stop mode. (Refer to
tion.)
and is operating with a single IMB clock per time quantum, there can be extreme
cases in which TouCAN wake-up on recessive to dominant edge may not con-
form to the CAN protocol. TouCAN synchronization is shifted one time quantum
from the wake-up event. This shift lasts until the next recessive-to-dominant edge,
which resynchronizes the TouCAN to be in conformance with the CAN protocol.
The same holds true when the TouCAN is in auto power save mode and awakens
on a recessive to dominant edge.
awaiting transmission in any message buffer
MPC556
CAN 2.0B CONTROLLER MODULE
Rev. 15 October 2000
16.4.2 TouCAN Initializa-
MOTOROLA
16-18