I am working with hack-rf one and GNU radio. I have one hack-rf one device and i am trying to transmit and receive signals continuously. Is there any module in GNU radio which makes it possible?
Currently i have a flowchart for receive and one for transmit.
I am using selector block but manual switching isnt working properly.
I need to send and receive the same signals after reflection and study the difference.
Any suggestion is welcomed.
Since that is physically impossible for the device: No, no software on this earth can do that for you.
I have a PIC32MX340F512 board developed by another company for us, The board has a DS1338 RTCC and 24LC32A eeprom, and display unit on an I2C bus, on this bus i included a TSL2561 I2C light sensor, i wrote code in c to poll the light sensor continously , when the light sensor reaches a certain level i save the time and date and light sensor value on SD card. This all works fine but if i leave the system without exposure to light inside tunnel where incident light on one end of the tunnel is ought to be monitored the system becomes unresponsive no matter how much amount of light you apply and then if i switch power off and back on again everything starts to work normal. i am a one man development team and have been trying to find out the problem for months, i activated the watchdog timer to prevent the system from hanging but the problem still persisted. i then decided to find out if the problem is with the sensor by including a push button to activate light measurement but still when 4-5 hours elapse the PIC cant even detect a change in the the input pin. Under the impression that a hardware reset overrides anything going on i included a reset button and it also works ok for the first few hours after that the PIC doesn't seem to be responding to anything including a reset. I was getting convinced that there is nothing wrong with the firmware but also with all this happening the display unit (pic16f1933 and lcd) on the I2C shares power with the main unit and doesn't seem to be affected as it alternates between different messages constantly Does anybody have an idea what could be wrong (hardware/firmware or my sensor). I am using a 24v DC power supply purchased seperately. The PIC seems to go into a deep sleep although i dd not implement any kind of SLEEP mode in my code. Nb We use the same board for many other projects and i haven't come across such a problem . Thanks in advance.
I think you need to (if you haven't already) explore the wonderful world of in-circuit-debugging (such as with the ICD3 or PICkit 2/3). It allows you to run the processor in a special mode that lets you pause execution, see exactly which line of code is being executed, inspect variable values, and step through the code to see which parts are running and not running, or see exactly where execution takes a wrong turn. If the problem takes hours to reproduce, that's okay. You can just leave it overnight running in debug mode and hopefully it will be locked-up or 'sleeping' in the morning. At this point, you will be able to pause the processor and poke around to see if you got caught in some kind of infinite loop or something. This is often the only way to dig inside a running piece of code to see why things aren't working as you expect. But as you say, those bugs that take hours or days to manifest are the trickiest. Good luck!
It sounds like you can break up your design into two main parts, sd card interfacing, reading the rtc and reading the light sensor. If it were me I would upload a version of the code that mimics reading the light sensor but only returns fake data and see if that cures the problem. Additionally do the same with the other two modules separately and see if any of the three versions of your project not show this problem. From there just keep narrowing it down until you find the block of code thats causing problems.
if Two or more versions of your debug code show the same problem then my guess is it has to do with one of the communication protocols. I had a problem with a Pic32 silicon version blocking when using the DMA in conjunction with the SPI peripherals. So I would suggest checking the errata for your chip.
If you still cant find the problem, my only suggestion would be to check for memory leaks or arrays that are growing into reserved memory.
Hope that helps, good luck!
This is a little off the beaten path. I've got a DLink DWL-G520 card I'm using under OpenBSD and it works fine. What I want to do is be able to access the radio part of it. Why? I want to use it in a radio telescope. It's a 2.4 GHz receiver with an external antenna connector. I want to connect some coax, some amplifiers, and an old TV dish and point the dish at the sky. It has an RSSI signal and variable RF gain (which it adjusts, from what I can find) so all I'd need to do is record those over time while pointed at a certain spot in the sky. I don't need to control the frequency really since most natural events are broadband.
I'm poking through the OpenBSD ath driver following nested structs but I don't want any of the normal network stuff, which is most of what the driver does. dmesg identifies it as an AR5212 which according to the Atheros PDF is always paired with an AR2112 radio. Is there any easier way than wading through PCI stuff to see what my options are? I need to turn the transmitter off so it doesn't fry my amps too. Trying to find low level documentation is about impossible from what I've seen. Ultimately I'd like to have this work with other WiFi cards too, but I'll start with this one. I've got a Cistron with an external antenna connector also.
Alan, ab1jx
We need to drive 8 to 12 monitors from one pc, all rendering different views of a single 3d scenegraph, so have to use several graphics cards. We're currently running on dx9, so are looking to move to dx11 to hopefully make this easier.
Initial investigations seem to suggest that the obvious approach doesn't work - performance is lousy unless we drive each card from a separate process. Web searches are turning up nothing. Can anybody suggest the best way to go about utilising several cards simultaneously from a single process with dx11?
I see that you've already come to a solution, but I thought it'd be good to throw in my own recent experiences for anyone else who comes onto this question...
Yes, you can drive any number of adapters and outputs from a single process. Here's some information that might be helpful:
In DXGI and DX11:
Each graphics card is an "Adapter". Each monitor is an "Output". See here for more information about enumerating through these.
Once you have pointers to the adapters that you want to use, create a device (ID3D11Device) using D3D11CreateDevice for each of the adapters. Maybe you want a different thread for interacting with each of your devices. This thread may have a specific processor affinity if that helps speed things up for you.
Once each adapter has its own device, create a swap chain and render target for each output. You can also create your depth stencil view for each output as well while you're at it.
The process of creating a swap chain will require your windows to be set up: one window per output. I don't think there is much benefit in driving your rendering from the window that contains the swap chain. You can just create the windows as hosts for your swap chain and then forget about them entirely afterwards.
For rendering, you will need to iterate through each Output of each Device. For each output change the render target of the device to the render target that you created for the current output using OMSetRenderTargets. Again, you can be running each device on a different thread if you'd like, so each thread/device pair will have its own iteration through outputs for rendering.
Here are a bunch of links that might be of help when going through this process:
Display Different images per monitor directX 10
DXGI and 2+ full screen displays on Windows 7
http://msdn.microsoft.com/en-us/library/windows/desktop/ee417025%28v=vs.85%29.aspx#multiple_monitors
Good luck!
Maybe you not need to upgrade the Directx.
See this article.
Enumerate the available devices with IDXGIFactory, create a ID3D11Device for each and then feed them from different threads. Should work fine.
I know that in a CAN controller if the error count reaches some threshold (say 255), bus off will occur which means that a particular CAN node will get switched off from the CAN network. So there won't be any communication at all. But what if the above said scenario happens while the car is moving which contains the ECU (includes the CAN controller)?
Is there any auto-recovery mechanism in a CAN controller to avoid any of the above situations?
During bus off, the node will be isolated.
CAN waits for the mandatory time period, 128 x 11 bits (1408 bits - 5.6 ms for a 250 kbit/s system) of time, and then tries to re-initialize the node.
Yes, if a CAN Tx error count reaches 255, a node will turn off and potentially reset itself. A good implementation will not continue resetting a node if the problem persists.
In addition to this safety mechanism, ECU's (electric control units) also time the duration between valid transmissions of the messages they expect to receive. Therefore, if the engine controller goes offline, nearly every ECU in the vehicle will report "Lost Communication with the Engine Controller."
Typically, these type of CAN problems are identified by DTC's (diagnostic trouble codes) beginning with U, like this one: http://www.obd-codes.com/u0115
Depending on the severity of the issue, the vehicle might enter a "limp home" mode, or might be totally disabled. Problems with the CAN bus on a vehicle are extremely rare, unless there has been some tampering.
The recovery mechanism depends on the software stack that's being used. Most new vehicles have AUTOSAR compliant software implementations. In the AUTOSAR communication stack, the CanSM (state manager) module has configurable BusOff Monitoring and Recovery. You can read more at http://autosar.org .
A BusOff however, is a serious situation in a running vehicle. How this is handled at the vehicle level is very specific to the system design. But, in most cases the system would go into a safe mode of operation and all parameters would take pre-set fault values to let the vehicle run with a reduced functionality. You would see the warning lamps on the dash go off to alert the driver. ECUs typically comply with some level of ASIL (https://en.wikipedia.org/wiki/Automotive_Safety_Integrity_Level) standard. This makes sure that such situations are thought of and taken care of during design and development.
Nothing spectacular will happen, even if the Engine Control Unit looses CAN communication. The car will continue running.
When bus-off occurs, the CAN network isolates that node and then resets that node which can able to start communication.
As you mentioned, after reaching a specific error count, that node gets disconnected/prohibited from transmitting anything on the bus. This is a description for the bus side.
On the controller side, every CAN controller generates an interrupt on BUS_OFF. It is the controller's responsibility that it should reset the CAN controller and bring it back to the normal state.
This is strictly followed for every CAN controller in any car. And this all happens in a few milliseconds... So for the driver, nothing happens!
When the ECU detects a BUS_OFF fault, the ECU should stop its emissions so this is a good question to ask.
There is an auto-recovery mechanism:
For the first three detections, the CAN controller resets its registers without a delay
For the next detections, the ECU waits 1 second before the reset
There is something called limp-home mode for the cars. That is the condition when all the ECUs fail in the car network. Then a set of default parameters for the ECUs are initialized and then the system, i.e., your car can continue running only for some time before it is properly serviced by the OEM.
I know this is an old thread, but the answers are a bit different from the situation I have observed, in relation to the OP question.
From experience, I'm have an issue where my ECU stops communicating with the diagnostic tools while the engine is running, apparantly it has entered the CAN off state. The only reason I know is I have a OBD 2 plug in monitor for engine parameters. I don't get ANY DTC, well most of the time anyways.. sometimes I get DTCs that are not applicable to my vehcile, and some U codes.
That said, the vehicle continues to run just fine, and if I didn't have the plug-in monitor, I would have no idea there was a problem! I'm now pretty sure the ECU for the Engine is having communication problems, and hitting the error counter and shutting off, it's the only thing that makes sense. I checked the CAN signals with a 2 channel O-scope, and they are a bit noisy compared to one of my other cars, so my next step is to swap the ECU and see if that fixes it. I already swapped out the TIPM (Total Integrated Power Module), it serves as a router of sorts between the 2 CAN networks, to the OBD2 port. That apparantly wasn't it.
if a CAN Tx or RX error counter reaches 255 , the node will turn off and be isolated
What happens if a bus-off error occurs in a CAN controller while a car is in motion?
1)HARD SWAPPING can be done in can network.
eg: Assume four(4) nodes(ECUS) are connected in can bus network.if we disconnected one
ecus then also can bus works properly.
2)In BUSS OFF condition it can hear every signal on the bus network but it cant transmit
mssgs(signal). If the car in motion or in rest position.
eg: Ecus(ABS) are using for better performance but actual work is done by actuator(DISK BRAKE).