CANoe Tool Questions:
01. What is difference the between IG and G block in CANalyzer/CANoe tool?
Answer: There
are two limitations to the Generator block that limit its effectiveness in
complex tasks. The block is misleading for some people because it requires
multiple windows for setting up the transmit message list. The second problem
is the block settings have to be set before the CANalyzer measurement starts.
No changes can be made if the measurement is running.
Fortunately, CANalyzer has
another transmission block that eliminates both practical limitations: the
Interactive Generator block (IG).
The IG block
combines the configuration windows of the Generator block into one window;
therefore, everything can be setup in one spot. In addition, changes can be
made with the IG.
Without CAPL,can we simulate
the other ECU’s CAN Messages except Test ECU in the CAN Simulation Network in
CANoe tool without using IG or G blocks.
02. How to change the baud rate in CANoe without changing the code?
The bit rate may be changed
by either changing the oscillator frequency, which is usually
restricted by the processor
requirements, or by specifying the length of the bit segments in “time quantum”
and the prescaler value.
In Canoe tool, we can change
the bus timing register 0 & 1 values for correcting the baud rate.
In Autosar, we can use post
build configuration for CAN baudrate values.
03. What is environment variable?
Environment variables are
data objects global to the CANoe environment and are used to link the functions
of a CANoe panel to CAPL programs.
04. What is HIL and SIL testing?
Answer: Hardware-in-the-loop (HIL) simulation is
a technique that is used in the development and test of complex
real-time embedded systems. HIL simulation provides an
effective platform by adding the complexity of the plant under
control to the test platform. The complexity of the plant under control is
included in test and development by adding a mathematical
representation of all related dynamic systems. These mathematical
representations are referred to as the “plant simulation”. The embedded system
to be tested interacts with this plant simulation.
Hardware-In-the-Loop System is
an effective platform for developing and testing complex real-time embedded
systems. HIL system provides the complexity of the plant under control using
mathematical representation, called “plant simulation”, of all related dynamic
systems. It also includes electrical emulation of sensors and actuators which
act as the interface between the plant simulation and the embedded system under
test.
Advantages of HIL System
- Provides Cost Savings by Shortened Development time
- Complete, consistent test coverage.
- Supports automated testing
- Enables testing the hardware without building a “plant prototype”
- Simulator performs test outside the normal range of operation
- Supports reproducible test runs that can assist in uncovering and tracking down hard to find problems.
- Enables testing with less risk of destroying the system
SIL: SIL refers to the
kind of testing done to validate the behavior of the C-code
used in the controller. That code can be auto-generated from
the model used in algorithm development. Emmeskay has a deep
understanding of SIL testing and auto-code generation from the many SIL
projects we have performed for our customers.
Testing and Validation
- Plant model developed in vehicle simulation environment is imported to Simulink as a library.
- Controller is tested in loop with the plant for different routes and speed profiles.
- Controller is tested for different fault modes of the system using GUI VisualConnex
RTOS Question:
What is RTOS?
Real-Time Operating System
is a multitasking operating system intended for real-time applications. It is
used on every device/system needing real time operations that means operations
based not only on correctness but also upon the time (clock cycles) in which
they are performed.
In general, an operating
system (OS) is responsible for managing the hardware resources of a
computer and hosting applications that run on the computer. An RTOS performs
these tasks, but is also specially designed to run applications with very
precise timing and a high degree of reliability. This can be especially
important in measurement and automation systems where downtime is costly or a
program delay could cause a safety hazard. To be considered “real-time”, an operating
system must have a known maximum time for each of the critical operations that
it performs (or at least be able to guarantee that maximum most of the time).
Some of these operations include OS calls and interrupt handling. Operating
systems that can absolutely guarantee a maximum time for these operations are
commonly referred to as “hard real-time”, while operating systems that can only
guarantee a maximum most of the time are referred to as “soft real-time”.
Example:
Imagine that you are designing an airbag system for a new model of car. In this
case, a small error in timing (causing the airbag to deploy too early or too
late) could be catastrophic and cause injury. Therefore, a hard real-time
system is needed; you need assurance as the system designer that no single
operation will exceed certain timing constraints. On the other hand, if you
were to design a mobile phone that received streaming video, it may be ok to
lose a small amount of data occasionally even though on average it is important
to keep up with the video stream. For this application, a soft real-time
operating system may suffice. An RTOS can guarantee that a program will run
with very consistent timing. Real-time operating systems do this by providing
programmers with a high degree of control over how tasks are prioritized, and
typically also allow checking to make sure that important deadlines are met.
How Real-Time OSs
Differ from General-Purpose OSs?
Operating systems such as
Microsoft Windows and Mac OS can provide an excellent platform for developing
and running your non-critical measurement and control applications. However,
these operating systems are designed for different use cases than real-time
operating systems, and are not the ideal platform for running applications that
require precise timing or extended up-time. This section will identify some of
the major under-the-hood differences between both types of operating systems,
and explain what you can expect when programming a real-time application.
Interrupt
Latency
Interrupt latency is
measured as the amount of time between when a device generates an interrupt and
when that device is serviced. While general-purpose operating systems may take
a variable amount of time to respond to a given interrupt, real-time operating
systems must guarantee that all interrupts will be serviced within a certain
maximum amount of time. In other words, the interrupt latency of real-time
operating systems must be bounded
Unanswered Interview Questions If
you know comment as reply)
What is the use of Passive
error node?
Error Passive receivers can
no longer interrupt the data transfer as a recessive Error Flag does not
influence the bus levels. An Error Passive transmitter can still interrupt its
own message by sending a passive Error Flag. Attention, if one Receiver is in
error passive mode no data consistency is guaranteed any more.
How to find the bug in code
using debugger if pointer is pointing to a illegal value?
If two CAN messages with
same ID sending at a same time, different data which can node will gain
arbitration? How to test it?
Is it possible to declare
struct and union one inside other? Explain with example
- Spi and I2C difference.?
- What is UDS advantages?
- What is cross compiler
- Unit/integration/all testings.
- Regression testing.
- Test case types.
- Malloc calloc
- Function pointers Advantage where it is used?
How many can database files
are required for CAN Network simulation in CANoe tool.
what is the difference
between CANalyzer,CANoe and CANape tools?
Mention the few uses of the
CANoe tool?
what is a panel is CANoe
Tool and its Use?
Why CAPL scripting is used
in CANoe tool?
Is it possible to simulate
other ECU’s Except Test ECU without CAPL Scripting in CANoe tool?
what is purpose of CCP
protocol which is also used in CANape tool?
I really like it when individuals get together and share thoughts.
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