MPC555CME Freescale Semiconductor, MPC555CME Datasheet - Page 591

• 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

16.3.3.1 Configuring the TouCAN Bit Timing
16.3.4 Error Counters
MPC555
USER’S MANUAL
quanta clock operates at the S-clock frequency.
clock, CAN bit rate, and S-clock bit timing parameters. Refer to
Model
The following considerations must be observed when programming bit timing func-
tions.
The TouCAN has two error counters, the transmit (Tx) error counter and the receive
(Rx) error counter. Refer to
counters.The rules for increasing and decreasing these counters are described in the
CAN protocol, and are fully implemented in the TouCAN. Each counter has the
following features:
Table 16-8 Example IMB Clock, CAN Bit Rate and S-Clock Frequencies
Frequency
IMB Clock
• If the programmed PRESDIV value results in a single IMB clock per one time
• If the programmed PRESDIV value results in a single IMB clock per one time
• If the prescaler and bit timing control fields are programmed to values that result
• The TouCAN bit time must be programmed to be greater than or equal to nine
• 8-bit up/down-counter
• Increment by eight (Rx error counter also increments by one)
• Decrement by one
• Avoid decrement when equal to zero
/
quantum, then the PSEG2 field in CANCTRL2 register must not be programmed
to zero.
quantum, then the information processing time (IPT) equals three time quanta;
otherwise it equals two time quanta. If PSEG2 equals two, then the TouCAN
transmits one time quantum late relative to the scheduled sync segment.
in fewer than 10 IMB clock periods per CAN bit time and the CAN bus loading is
100%, then any time the rising edge of a start-of-frame (SOF) symbol transmitted
by another node occurs during the third bit of the intermission between messag-
es, the TouCAN may not be able to prepare a message buffer for transmission in
time to begin its own transmission and arbitrate against the message which trans-
mitted the early SOF.
IMB clocks, or correct operation is not guaranteed.
(MHz)
MPC556
25
20
16
25
20
16
for more information on the bit timing registers.
CAN Bit Rate
(MHz)
0.125
0.125
0.125
1
1
1
CAN 2.0B CONTROLLER MODULE
16.7 Programmer’s Model
Possible S-Clock
Frequency (MHz)
Rev. 15 October 2000
1, 1.25, 2.5
1, 2, 2.5
10, 20
8, 16
1, 2
25
Possible Number of
Time Quanta/Bit
Table 16-8
8, 16, 20
8,10, 20
10, 20
8, 16
8,16
25
for more information on error
provides examples of IMB
PRESDIV Value + 1
16.7 Programmer’s
25, 20,10
20, 10, 8
16, 8
2, 1
2, 1
1
MOTOROLA
16-9