33889 Datasheet, PDF (35/60 Pages) Freescale Semiconductor, Inc – System Basis Chip with Low Speed Fault Tolerant CAN Interface

FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
Recessive
state
CANL
Dominant
state
CANH
CANL terminated to Vbat
Other CAN node send
Recessive
state
Dominant
state
Rx
T_WAKE
T_WAKE
CAN in TxRx
CAN in TermVbat
CAN in TxRx
MC33889D in Normal mode _{MC33889D in Normal mode, Standby mode or in stop mode MC33889D in Normal mode}
T_WAKE: duration of the CAN wake up filter, typ 16µs. The MC33889D Rx dominant low level duration is the difference
between the duration of the bus minus the Twake, as illustrated below (Trx_dom = Tbus_dom - Twake)
Tx sender node
Example: A dominant duration at the bus level of 5
bits of 8us each results in a 40us bus dominant.
This results in a 24µs (40µs-16µs) dominant level at
Rx of MC33889D (while the CAN of the MC33889D
is in TermVbat).
Tx MC33889D
Rx MC33889D
Dominant state
T_WAKE
TRX_DOM
TBUS_DOM
Figure 15. Bus State Report of the CAN Interface Wake-Up Comparator on CANL and CANH
Analog Integrated Circuit Device Data
Freescale Semiconductor
33889
35