I'm rather unexperienced on the field of microcontrollers, I come from a Java background so the question might seem a bit noob but I didn't find much information on this.
So is it possible to debug an STM32F4 board via bluetooth (using eclipse or some othe IDE)? And if so could you send me some links that might help? We're building a robotic car controlled by a discovery board and debugging using an USB cable is not really an option if we don't want to disassemble the whole stuff every time something goes wrong. Hence this would really come in handy. So any help is appreciated
For doing this you would need to find a "Bluetooth Enabled" Debugger. I have never seen any and not sure whether there exists such thing or not.
I would suggest you one thing:
Assuming you have bluetooth connectivity between your board and your Machine,
Insert Debug strings: Send some strings from your board to your PC via Bluetooth. These strings will give you what's going on in Circuit.
For example, After Initialization, send "Init Completed" and like that. You can see these strings and see what's wrong.
I usually do this for my Wireless Device.
What you're wanting to do is really not practical; you're coming at this from way too high a level and trying to imagine the system as if it were running an operating system from the word go.
When you get the STM32 it as empty shell; you need to program it to do what you need to do and the only [sensible] way to get register-level debugging is to use a JTAG interface.
If, and this is a big if, you get it working reliably, but just want to give some debug information back while it is running, you could write a load of routines within the code to send out debugging messages when it enters certain parts of the program - and send it out over Bluetooth - but this is nothing like what you're used to single stepping through your Java code with Eclipse. If you want to do that kind of thing, you are going to have to put a little connector on that allows you to connect your JTAG or two-wire debugger cable to the processor. Even then, when you do that, you will be completely resetting your program and not simply single stepping through from where it went wrong.
You could insert a monitor program within your program to send out register values, program status etc over Bluetooth, but you still have to write the inital code and the only way to do this with out a ridiculous amount of trail and error is via your JTAG or two-wire interface.
Would this product work? It's a "IOGEAR Bluetooth Serial Adapter, GBC232A" for connecting to a serial port over bluetooth. I'm interested in wireless debugging too because my surface-clone dev computer only has one usb and this seems like it could be convenient over a tangle of usb cords and a usb hub. I have zero experience with any of this, so maybe you could validate or invalidate it as an option. I figure it just needs a proper serial connector wired up on the board and power from on-board?
Related
I want to create an application or modify USB in a way so that, upon insertion into any PC, I can get the information that PC was inserted.
eg. upon insertion, I can read PC name and make an API call with this as post data so I'm able to know that my USB was inserted in some PC. But this should happen right away as USB is read by the machine, so even if the user formats it thereafter, it should not matter.
If it was earlier windows, I could write autorun and that would work. But I want this detection mechanism for Windows 7 and above.
I have done some research on the topic but could not find any reliable content. Some articles were related to USB based hacking attacks by changing wiring (USB hardware, to harm the computer) or something like that. But I totally don't want to do that. Just the detection, that USB was used.
I am programming a pci device with verilog and also writing its driver,
I have probably inserted some bug in the hardware design and when i load the driver with insmod the kernel just gets stuck and doesnt respond. Now Im trying to figure out what's the last driver code line that makes my computer stuck. I have inserted printk in all relevant functions like probe and init but non of them get printed.
What other code is running when i use insmod before it gets to my init function? (I guess the kernel gets stuck over there)
printks are often not useful debugging such a problem. They are buffered sufficiently that you won't see them in time if the system hangs shortly after printk is called.
It is far more productive to selectively comment out sections of your driver and by process of elimination determine which line is the (first) problem.
Begin by commenting out the entire module's init section leaving only return 0;. Build it and load it. Does it hang? Reboot system, reenable the next few lines (class_create()?) and repeat.
From what you are telling, it is looks like that Linux scheduler is deadlocking by your driver. That's mean that interrupts from the system timer doesn't arrive or have a chance to be handled by kernel. There are two possible reasons:
You hang somewhere in your driver interrupt handler (handler starts its work but never finish it).
Your device creates interrupts storm (Device generates interrupts too frequently as a result your system do the only job -- handling of your device interrupts).
You explicitly disable all interrupts in your driver but doesn't reenable them.
In all other cases system will either crash, either oops or panic with all appropriate outputs or tolerate potential misbehavior of your device.
I guess that printk won't work for such extreme scenario as hang in kernel mode. It is quite heavy weight and due to this unreliable diagnostic tool for scenarios like your.
This trick works only in simpler environments like bootloaders or more simple kernels where system runs in default low-end video mode and there is no need to sync access to the video memory. In such systems tracing via debugging output to the display via direct writing to the video memory can be great and in many times the only tool that can be used for debugging purposes. Linux is not the case.
What techniques can be recommended from the software debugging point of view:
Try to review you driver code devoting special attention to interrupt handler and places where you disable/enable interrupts for synchronization.
Commenting out of all driver logic with gradual uncommenting can help a lot with localization of the issue.
You can try to use remote kernel debugging of your driver. I advice to try to use virtual machine for that purposes, but I'm not aware about do they allow to pass the PCI device in the virtual machine.
You can try the trick with in-memory tracing. The idea is to preallocate the memory chunk with well known virtual and physical addresses and zeroes it. Then modify your driver to write the trace data in this chunk using its virtual address. (For example, assign an unique integer value to each event that you want to trace and write '1' into the appropriate index of bytes array in the preallocated memory cell). Then when your system will hang you can simply force full memory dump generation and then analyze the memory layout packed in the dump using physical address of the memory chunk with traces. I had used this technique with VmWare Workstation VM on Windows. When the system had hanged I just pause a VM instance and looked to the appropriate .vmem file that contains raw memory latout of the physical memory of the VM instance. Not sure that this trick will work easy or even will work at all on Linux, but I would try it.
Finally, you can try to trace the messages on the PCI bus, but I'm not an expert in this field and not sure do it can help in your case or not.
In general kernel debugging is a quite tricky task, where a lot of tricks in use and all they works only for a specific set of cases. :(
I would put a logic analyzer on the bus lines (on FPGA you could use chipscope or similar). You'll then be able to tell which access is in cause (and fix the hardware). It will be useful anyway in order to debug or analyze future issues.
Another way would be to use the kernel crash dump utility which saved me some headaches in the past. But depending your Linux distribution requires installing (available by default in RH). See http://people.redhat.com/anderson/crash_whitepaper/
There isn't really anything that is run before your init. Bus enumeration is done at boot, if that goes by without a hitch the earliest cause for freezing should be something in your driver init AFAIK.
You should be able to see printks as they are printed, they aren't buffered and should not get lost. That's applicable only in situations where you can directly see kernel output, such as on the text console or over a serial line. If there is some other application in the way, like displaying the kernel logs in a terminal in X11 or over ssh, it may not have a chance to read and display the logs before the computer freezes.
If for some other reasons the printks still do not work for you, you can instead have your init function return early. Just test and move the return to later in the init until you find the point where it crashes.
It's hard to say what is causing your freezes, but interrupts is one of those things I would look at first. Make sure the device really doesn't signal interrupts until the driver enables them (that includes clearing interrupt enables on system reset) and enable them in the driver only after all handlers are registered (also, clear interrupt status before enabling interrupts).
Second thing to look at would be bus master transfers, same thing applies: Make sure the device doesn't do anything until it's asked to and let the driver make sure that no busmaster transfers are active before enabling busmastering at the device level.
The fact that the kernel gets stuck as soon as you install your driver module makes me wonder if any other driver (built in to kernel?) is already driving the device. I made this mistake once which is why i am asking. I'd look for the string "kernel driver in use" in the output of 'lspci' before installing the module. In any case, your printk's should be visible in dmesg output.
in addition to Claudio's suggestion, couple more debug ideas:
1. try kgdb (https://www.kernel.org/doc/htmldocs/kgdb/EnableKGDB.html)
2. use JTAG interfaces to connect to debug tools (these i think vary between devices, vendors so you'll have to figure out which debug tools you need to the particular hardware)
I'm trying to program some tool and i want to simulate a network cable lose with it.
So i want to get the same effect like i unplug the networkcable from my computer and plug it in again. It's not the same as the '/renew' / '/release' commands. When i disconnect / connect it manualy it look likes windows remember some things and it's connected very fast back again.
Is it possible and maybe how to do it in code?
Thank you very much!
edit:
I found another program that just blocks all ports, this is ok for me too but how to do in code :).
You should set the fetch and send data bitrate to 0
Alternatively you could just set the receive bitrate to 0 bits and leave the send untouched this would also simulator the same.
Check out a great little tool called WANem . You can use it to simulate different WAN scenarios. Loss of connectivity is one possibility, but also jitter, noise and more on the line. Even simulating a dial-up connection. Runs as a bootable ISO and very easy to use.
Got a customer request but no idea can it be done. So need your opinions on this. This might be a utterly stupid thing to ask but yet need some facts so can work out best solution.
Scenario,
My Customer is an OEM Manufacturer. They make an automated system with a embedded touch screen (Windows XPe) this system got a button panel with some LED indicators (apart from keyboard) and 7 USB Ports. These button panels and USB ports are checked before sending to QC process. Currently a USB thumb drive with standalone executable with all indicators and controls flags is inserted to one of the USBs and then will run the exe. This exe capture user inputs from button panel and indicate which button is pressed so that it can be verify as working. And from program user can set LED indicators to different states (flashing, steady and off) so they can be verified as well. Once this is done then USB thumb drive will be inserted to each port and will verify it recognise. But after each verify step it needs to safely remove the drive from task bar. Once each test is finish user required to fill up the sheet with all pass and fail states for the entire button panel, indicators and USB ports. This is a quite length process when its come to mass production.
Apart from this embedded system all other components which suppose to connect to one of above embedded systems are tested via a program which I make and records all test outputs as they are tested. This program installed and components are connected to a testing embedded system.
Requirement,
What customer asks, can my program test completed embedded system with our host system (testing embedded system, may be via USB to USB) Its more like Testing a PC from another PC. Any ideas ?
Additional Info.
Apart from USBs there is one Network Port.
Thanks for looking, Feel Free to ask any questions. Any opinion is appreciated.
I'm not an expert on this topic, but it seems like this would be problematic because USB is an assymetrical protocol. There are hosts and there are devices. Hosts make the requests, and devices fulfill the requests. The problem is that PCs are USB hosts, not USB devices, so you would have two hosts trying to get the guy on the other side to do what he wants. Testing with a USB thumb drive worked because the thumb drive is a device.
It sounds like the unit to be tested doesn't have an ethernet port, which is a shame, because that would be the easiest way to go. If it has a serial port you could do it that way, but that is both slow and a hassle.
I am trying to make U9 telit modem send SMS messages. I think I handle protocol correctly, at least, I manage to send them, but only under these circumstances: the native application was executed beforehand, and killed by task manager (without giving it a chance to initialize things).
It looks like the supplied application is good at doing certain initialization/deinitialization which is critical. I also see the difference between the two states in output of AT+CIND command. When I am trying to do things on my own, it returns zeroes (including signal quality), but when I run the same command after killing the native application, the output looks reasonable.
I am out nearly of ideas. I have tried many things, including attempts to spy at modem's COM ports (didn't work). Haven't tried setting windows hooks to see what the application is trying to get thru.
Perhaps you have encountered a similar situation?
Agg's "Advanced Serial Port Monitor" actually helped a lot. Sometimes it caused blue screen, but it helped uncover secret commands which seem to help. AT+PCFULL is not described anywhere on the net, for example. The real trigger of non-operatio was AT+CFUN, the power disable/standby feature.
Also, it appeared that we have more issues. At first, the modem appears on the bus only as disk drive. It doesn't want to appear as any other devices before the drivers are installed. So, the U9 Telit software sends an IOCTL to disk driver to tell the modem to reappear as more devices (modem, 3 serial ports, another disk drive).