MPC555CME Freescale Semiconductor, MPC555CME Datasheet - Page 594

• 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

16.4.3 Transmit Process
MPC555
USER’S MANUAL
The transmit process includes preparation of a message buffer for transmission, as
well as the internal steps performed by the TouCAN to decide which message to trans-
mit. For the user, this involves loading the message and ID to be transmitted into a
message buffer and then activating that buffer as an active transmit buffer. Once this
is done, the TouCAN performs all additional steps necessary to transmit the message
onto the CAN bus.
The user should prepare or change a message buffer for transmission by executing
the following steps.
Once an active transmit code is written to a transmit message buffer, that buffer begins
participating in an internal arbitration process as soon as the receiver senses that the
CAN bus is free, or at the inter-frame space. If there are multiple messages awaiting
transmission, this internal arbitration process selects the message buffer from which
the next frame is transmitted.
3. Initialize mask registers for acceptance mask as needed
4. Initialize TouCAN interrupt handler
5. Negate the HALT bit in the module configuration register
1. Write the control/status word to hold the transmit buffer inactive (code =
2. Write the ID_HIGH and ID_LOW words
3. Write the data bytes
4. Write the control/status word (active Tx code, Tx length)
/
MPC556
a. The control/status word of all message buffers must be written either as
b. All other entries in each message buffer should be initialized as required
a. Initialize the interrupt configuration register (CANICR) with a specific
b. Set the required mask bits in the IMASK register (for all message buffer
a. At this point, the TouCAN attempts to synchronize with the CAN bus
0b1000)
an active or inactive message buffer.
request level
interrupts), in CANCTRL0 (for bus off and error interrupts), and in
CANMCR for the WAKE interrupt
In both the transmit and receive processes, the first action in prepar-
ing a message buffer must be to deactivate the buffer by setting its
code field to the proper value. This step is mandatory to ensure data
coherency.
Steps one and four are mandatory to ensure data coherency.
CAN 2.0B CONTROLLER MODULE
Rev. 15 October 2000
NOTE
NOTE
MOTOROLA
16-12