User manual
55
Serial Bus Analysis
❙ FRAME: The submenu offers different options, like
trigger on ERROR (general frame error), OVERLOAD
(trigger on CAN Overload frames) or DATA (trigger on
data frames). With the soft menu key READ/DATA you
are able to trigger on read and data frames. With the soft
menukeyIPTYPEtheidentiertype(11bit,29bitor
any.) can be selected.
❙ ERROR S: Identiesvariouserrorsinaframe.Thismenu
allows you to choose one or several error message types
as trigger condition. Individual frame segments (e.g.
framestartetc.)arecodedduringthebitstufng
procedure. The transmitter automatically adds a
complimentary bit to the bit stream if it detects 5
consecutive bits with identical value in the bit stream to
be transmitted. A “STUFF” error occurs if the 6th
identicalbitlevelisdetectedinthespeciedsections.A
FORMerroroccursifaxedbiteldcontainsoneor
several invalid bits. An authentication error occurs if the
transmitter receives no authentication (acknowledge).
CAN BUS applies a complex checksum calculation
(Cyclic Redundancy Check). The transmitter calculates
the CRC and transmits the result in a CRC sequence. The
receiver calculates the CRC in the same manner. A CRC
error occurs if the calculated result deviates from the
received CRC sequence.
❙ IDENTIFIER: Identiesthepriorityandthelogical
address of a message. In the menu that opens you can
press the top soft menu key to select the FRAME TYPE
(general data, read data or read/write data) via universal
knob. The soft menu IDENTIFIER SETUP below allows
youtospecifythelengthoftheidentiertypeviasoft
menu key ID TYPE and universal knob (11 bit base or 29
bits for extended CAN frames). The soft menu key
COMPAREdenesthecomparisonfunction.Ifthepattern
includes at least one X (don’t care), it is possible to trigger
onavalueequalornotequaltothespeciedvalue.Ifthe
pattern includes only 0 or 1, it is possible to trigger on an
areagreaterthanorlessthanthespeciedvalue.The
PATTERN INPUT may be binary or hexadecimal. If you
choose the binary input, the soft menu key BIT and the
universal knob allow you to select which individual bits
within the data are to be edited. Select the option STATE
to assign a logic state to each bit (High = H = 1, Low = L
=0orX=don’tcare).ThestateXdenesanystate.If
you choose the hexadecimal input, the soft menu key
VALUE and the universal knob allow you to set the value
for the respective byte. If the input is hexadecimal, only
the entire byte can be set to X. Use the soft menu key
BYTE to toggle between bytes.
❙ IDENTIFIER AND DATA: Includes the same settings as
the soft menu IDENTIFIER. In the menu that opens you
can select the FRAME TYPE (general data or read data)
via top soft menu key and universal knob. In the menu
IDENTIFIER SETUP below you can enter the address of
the respective pattern.
❙ DATA SETUP: Allows you to specify the data bit pattern
or HEX values for up to 8 bytes (only available if DATA
was selected as frame type). Available comparisons for
address and data values are GREATER, EQUAL OR LESS,
EQUAL and NOT EQUAL.
Press the MENU OFF button several times to close all me-
nus, and the oscilloscope will trigger on the set data. For
measurements without measuring object please refer to
chapter 12.2.2.
12.8 LIN BUS
The LIN bus (Local Interconnect Network) is a simple mas-
ter/slave bus system for automotive applications and is
used for the data exchange between controller units and
sensors or actuators. The signal is transmitted on one line
with ground reference to the vehicle mass. A LIN BUS has
the following properties:
❙ Serial single-wire communication protocol (byte-oriented)
❙ Master-slave communication (generally up to 12 knots)
❙ Master-controlled communication (master initiates /
coordinates communication)
The data is transmitted in bytes without parity (based on
UART). Each byte consists of a start bit, 8 data bits and a
stop bit.
Fig. 12.20: CAN BUS
For CAN BUS trigger and decoding you need the R&S®HOO12 op-
tion or the upgrade voucher R&S®HV112.
Fig. 12.19: CAN data trigger menu