Trying to edit Flexray_UNIFIED_cfg.c in Freescale NCV7383 demo (using CW5.1 and MC9S12XF512) to send bigger packets with different frame IDs to match my automotive target system. Any of youse guys ever grok flexray? Thanks.
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I'm trying to implement the UPLINK of a Ground Station controlling a small satellite. The idea is that the link should stay always active in between each transmitted telecommand. For this, I need to insert some DUMMY or IDLE sequence bytes such as 0xAA or similar.
I have found that some people already faced a similar issue and posted their questions here:
https://www.ruby-forum.com/t/constant-carrier-digital-transmission/163379
https://lists.gnu.org/archive/html/discuss-gnuradio/2016-08/msg00148.html
So far, the best I could achieve was to modify the EventStream Source block from https://github.com/osh/gr-eventstream in order to preload the vectors with my dummy sequence (i.e. 0xAA) instead of preloading them with zeroes. This is a general overview of the GNURadio graph I'm using:
GNURadio Flowgraph Picture
This solution however introduces a huge latency and the sent message does not appear at the output until a huge amount of time has expired (in the order of several seconds).
Is there a way of programming the USRP using GNURadio so that it constantly sends a fixed sequence which should only be interrupted when an incoming message is passed? I assume that the USRP has the ability of reading tagged streams in order to schedule transmissions. However, I'm not sure how to fit this in my specific application.
Thanks beforehand!
Joa
I believe this could be done using a TCP or UDP source block.
Your control information could be sent to the socket using TCP/UDP. GNU Radio would then collect and transmit the packets. Your master control program would then have to handle the IDLE stuffing but solving the problem external to GNU Radio is easier.
Your master control program would basically do the following:
1. tx control data as needed
2. if no control data ready before next packet must be sent send an IDLE packet
I'm currently working on a c project, having an XBee Pro Series 1 on my pc, allowing me to send data to my nibo2 roboter, also having that xbee module attached.
Sending data from the nibo2 roboter to my pc works great and there is no kind of data loss.
Sending data from my pc to the nibo2 works not fine:
When I'm trying to send 16 Bytes at one point of time, only the first 8 Byte arrive at my nibo2. The second 8 Byte are lost. When i send the data split into 8 Bytes and send them with a time difference of maybe 1s - 2s, it works fine.
The maybe interesting things you should know about this, are listed here:
XBee Datasheet: http://ftp1.digi.com/support/documentation/90000982_H.pdf
The used library for the roboter (using uart0): http://nibo.sourceforge.net/doc/html/
Does anyone have an idea or does someone know the problem? Is it a thing about configuring the xbee module? interrupt problem?
Thanks a lot.
How have you configured the XBee modules? Which firmware version? What baudrate? Are you using hardware flow control (CTS and RTS signals)?
Can you use the "Assemble Packet" button on Terminal tab of X-CTU on the PC to send the 16-byte packet and have it received properly?
Can the serial port of the NIBO2 handle 16 bytes in one request? Does it work if you use a wired connection instead of wireless?
I know there are various programs that sniff packets like WireShark, but I'm pretty sure you can only view the data. I want to know if it's possible to edit incoming packets. I'm not sure if packets are the right term. I just want to edit incoming data that is recieved through the internet and who's destination is a specific application. Let's say I am playing an online game. As it loads my computer, it is recieving information like "This person has 10 coins in their money pouch". Obviously not exactly like that but you get the point. I would like to be able to change the data so it is say 100 instead of 10. I know something like this would be possible if you were to do this: Imagine my computer is connected to the internet with an ethernet cord. There is a device attached to the ethernet cord which recieves the data and changes it and then lets it continue to my computer. I would just like to know if this is possible, and how it could be accomplished.
Thanks!
The way I do it, is one of 2 ways:
1.
If your application supports it set up a HTTP Proxy on your machine and you could software like burp / Fiddler to mess with the data
If not (the protocol is not HTTP) you could use either one of 2 options i'v tried [Both based on Hooking the API calls from the application to the OS]:
EchoMirage software that allow messing around with the packets
[Bit more advanced: ] There is a debugger named OllyDbg which has a plugin named Universal Hooker; it enables to hook any window API function and execute a python script on demend. the uHooker contains examples for how to hook WSASend and WSARecive (which are the API functions used in windows sockets).
Over the past two days, I am doing some reading on how to get data over USB from an external device which has no device driver installed. I have to read data from a WT500 Yokogawa Power Meter (basically I want to read just one of the parameter that the meter shows, just the power values) over USB. I am aware that a device driver for WT500 is available, but it has some dependencies and I do not want to install a software or change anything majorly in our node to cater to that.
I have found that libusb could be used to perform what I would want, and I have a C program that sniffs the USB device and returns some information. I have looked into usb-robot as well, which also uses libusb. The server node that I am probing has OpenSUSE Linux kernel 2.6.30. I have usbfs mounted.
Question:
I am expecting that using libusb, I would be able to get data dumps from the power meter whenever I request, via usb device. Can I request the meter something like - send 25k of data, and then upon parsing it, I get the parameter value that I am looking for? Considering that I have zero knowledge about the device, can I get some meaningful values out of it? An example code would help.
--
There are some standard messages like ?IDN with which a USBTMC device could be queried. However, specific queries need to be sent to a meter (the syntax should be there in the technical doc/manual/communication interface) if one needs to get whatever is showing up on screen.
I guess there are no easier ways of doing what I want - like just reading a file using something like fread ??
--
Yes, almost. If USBTMC module is installed (the default one in our kernel did not work, detailed explanation of installing and querying a device is here - http://code.google.com/p/scte/wiki/USBTMC), then one just needs to send some queries and read the response via cat or something from the specific files under /dev.
From the meter technical document, I see that the driver communication interface that is described is Windows specific, so I reckon I might need to do some reverse engineering.
--
Yes, but only a tiny bit or may be not at all.
Thank you.
EDIT: After a bit of googling I think I have the answers, I have added them next to the questions I asked.
If I understand the parallel port right, sending data from (D0 to D7) simultaneous, but that it can control the sticks individually?
example:
D0 = Input
D1 = Input
D2 = Output
...
...
...
D7 = Input
would it work?
what I want to do is to both send and receive data simultaneously.
Data wires (D0-D7) are being read or set simultaneously. For various tecniques for bidirectional I/O read the attached articles:
Standard parallel port: http://www.beyondlogic.org/spp/parallel.htm
EPP: http://www.beyondlogic.org/epp/epp.htm
ECP: http://www.beyondlogic.org/ecp/ecp.htm
This site is a good source for programming the parallel port.
The basic idea is that you need a DLL, add-on or library that allows you to access the I/O Ports of the PC. For Windows XP on up you need a specific driver that will allow you do this as the OS doesn't offer access out of the box.
The Parallel port will generally reside at one of three address 278,378, 3BC. This port. have the bytes you are reading or writing.
The (base)+1 port allows access to the status bytes. IE. 279,379, 3BD
The (base)+2 port allows access to the control bytes. IE. 27A,37A,3BE
The parallel port documentation will tell not only how to implement the common modes (like bi-directional) but how to control the port at the byte level to implement your own custom.
Back in the day there was only the standard mode available. You pump out your bytes at the (base) port. Some application, like mine, manipulated individual bits of that ports as form of cheap Digital I/O Controller. We did use the status and control bytes as additional inputs and outputs. There were commands you can send to the Parallel Port chip configure the modes precisely.
Today there are are hundreds of sites with example of using the Parallel Port to solve all kinds of problems. I would be surprised that one of doesn't have something you can use for you specific application.
Again the book I recommend starting with is Parallel Port complete. It tells just about everything you need to start with. If your application is too esoteric for that book it will give a springboard from which you can find the exact setup you need.
Of course by sending a number that has just the required bit set (2n) you'd get the expected result.
I'm not sure about bidirectional access though. I guess it's achieved by using control pins along with the data pins but that's just a guess.
Parallel ports doing EPP or ECP only allow D0-D7 to be all input or all output. Trying to do otherwise may fry your hardware.
See http://www.nor-tech.com/solutions/dox/ieee1284_parallel_ports.pdf, page 6.
However, parallel ports have several control lines that may be useful if you only need a small amount of input/output in the "other" direction.
I believe its bit 5 in the port's control register (base address + 2) that switches direction. (no hardware line attached)