TJA1041_6 © NXP B.V. 2007. All rights reserved.
Product data sheet Rev. 06 — 5 December 2007 5 of 26
NXP Semiconductors
TJA1041
High speed CAN transceiver
7. Functional description
The primary function of a CAN transceiver is to provide the CAN physical layer as
described in the ISO 11898 standard. In the TJA1041 this primary function is
complemented with a number of operating modes, fail-safe features and diagnosis
features, which offer enhanced system reliability and advanced power management
functionality.
7.1 Operating modes
The TJA1041 can be operated in five modes, each with specific features. Control pins
STB and EN select the operating mode. Changing between modes also gives access to a
number of diagnostics flags, available via pin ERR. The following sections describe the
five operating modes. Table 4 shows the conditions for selecting these modes. Figure 3
illustrates the mode transitions when V
CC
, V
I/O
and V
BAT
are present.
[1] X = don’t care.
[2] Setting the pwon flag or the wake-up flag will clear the UV
NOM
flag.
[3] The transceiver directly enters Sleep mode and pin INH is set floating when the UV
NOM
flag is set (so after
the undervoltage detection time on either V
CC
or V
I/O
has elapsed before that voltage level has recovered).
[4] When go-to-sleep command mode is selected for longer than the minimum hold time of the go-to-sleep
command, the transceiver will enter Sleep mode and pin INH is set floating.
[5] On entering normal mode the pwon flag and the wake-up flag will be cleared.
Table 4. Operating mode selection
[1]
Control pins Internal flags Operating mode Pin INH
STB EN UV
NOM
UV
BAT
pwon;
wake-up
X X set X X
[2]
Sleep mode
[3]
floating
cleared set one or both set Standby mode H
both cleared no change from Sleep mode floating
Standby mode from any
other mode
H
L L cleared cleared one or both set Standby mode H
both cleared no change from Sleep mode floating
Standby mode from any
other mode
H
L H cleared cleared one or both set Standby mode H
both cleared no change from Sleep mode floating
go-to-sleep command mode
from any other mode
[4]
H
[4]
H L cleared cleared X pwon/listen-only mode H
H H cleared cleared X normal mode
[5]
H
