55
Serial Bus Analysis
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 = 0 or X = don’t care). The
state X defines any state. 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. The soft menu 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 twice or three times to close
all menus, and the oscilloscope will trigger on the set data.
For measurements without measuring object please refer
to chapter 10.2.5.
13 .7 .3 CAN BUS Table
Tab. 13.5: Content of the CAN BUS table
Column
Description
Start Time
Time of frame start in relation to the trigger point
Type
Frame Type:
❙
DATA
= Data Frame
❙
REMOTE
= Remote Frame
❙
ERR-F .
= Transmission error (Error Frame)
❙
OVL-F .
= Overload Frame
ID
Frame ID
DLC
Data length code, number of data bytes
Data
Values of the data bytes
CRC
Cyclic Redundancy Check
State
Frame State:
❙
OK
= Frame is valid
❙
CRC
= the calculated result deviates from the
received CRC sequence (cyclic redundancy
check failed)
❙
NACK
= not Acknowledge
❙
CRC+NACK
= cyclic redundancy check failed
followed by „not Acknowledge“
❙
STUFF
= Bit Stuffing Error
❙
INS
= the frame is not completely contained in
the acquisition; the acquired part of the frame is
valid.
13 .8 LIN BUS
The LIN bus (Local Interconnect Network) is a simple
master/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.
13.8.1 LIN BUS Configuration
After choosing the BUS type LIN in the BUS menu press
the soft menu key CONFIGURATION. In the menu that
opens you can press the top soft menu key DATA to select
the desired channel via universal knob in the CURSOR/
MENU section. The soft menu key POLARITY allows you
to toggle between High and Low; the active function will
be highlighted in blue. An analog or a digital channel can
be connected to LIN-High or LIN-Low. You can select any
version for the LIN standard (version 1x, version 2x, J2602
or any) via soft menu key VERSION and universal knob.
The option BIT RATE allows you to specify the number
of transmitted bits per second. You can use the univer-
For CAN BUS trigger and decoding you need the R&S®HOO12
option or the upgrade voucher R&S®HV112.
Fig. 13.19: LIN byte structure
Prior to the
BUS configuration it is necessary to set the correct
logic level (threshold). Please refer to chapter 4.5. The default
setting is 500 mV.
Fig. 13.18: Example CAN BUS table
