I am using MSP430F5418 wit IAR EW 5.10.
In my project I am using FreeRTOS 7.0 as operating system.
Consider the scenerio:
Setup RTC in alarm mode with one minute interrupt.
Create two tasks.
When one minute interrupt arrives, send a request to task 2 by task 1.
Task 2 response to to task 1 with 4 messages.
While receiving messages task 1 calls a simple function which loops for 0x7FFF times.
Here, after the 4th request, an RTC interrupt is generated immediatly even if one minute is not passed.
I am using the Work-around code provided by TI for RTC manipulation.
Can anybody please tell me why this unexpected behaviour happens???
Thank you,
Hari
I would say that you have two options
Use the newer F5418A which has the RTC problems fixed.
Don't use the RTC
I have a project based on the 5418 that was ported from an F149, which does not have a hardware RTC. As part of the porting process use of the software RTC was replaced with the hardware module. The TI code was used but there were so many problems with the registers not writing properly that the software RTC was put back in.
Related
I was able to make a working HID USB stack on my "StartUSB for PIC" board for the 18F2550 microcontroller. I based it on one of the MLA libraries, which was made for the 18F45K50 (MLA 2018_11_26, hid_custom, picdem_fs_usb_k50.x), but I converted it to work with the 18F2550 (there might have been easier ways, but only learned to work with PIC about 1 month ago). On the host side, I'm using LibUsbDotNet (also here, there might be easier ways - the documentation on this library really sucks) on a Windows 10 machine.
I'm using the HID class, full speed, and all seems to work. Although, I get some random errors on the host PC (see below), but doing one close/re-open cycle on the host side when getting the error is kind of solving it. Dirty, but it works. So I kind of ignore this now.
Win32Error:Win32Error:GetOverlappedResult Ep 0x01
995:The I/O operation has been aborted because of either a thread exit or an application request.
I'm not an expert on USB (yet). But all examples I'm seeing are based on 1) you send first a command to the device and 2) then you retrieve the answer from the device. I did some performance tests, and see that this indeed shows that I can do about 500 cycles/second. I think that is correct, because each cycle, sending command and retrieving answer, each takes 1 msec.
But do I really need to send a command? Can't I just keep reading endlessly, and when the device has somthing to say, it does send the data in an IN transaction, and when not it ignores which creates a timeout on the host side. That would mean that I can poll at 1000 cycles/second? Unfortunately, I have tried it by changing my implementation on the PIC, but I get very weird results. I think I have issues with suspend mode. That brings me to another question - how can I make the device get out of suspend mode (means that not the host, but the device should be triggering this event). I have searched the MLA library for command such as "wakeup", "resume", ... but couldn't find anything.
So, to summarize, 2 questions:
Conceptual: Can I send data from device to host without being requested for it by a command from the host?
For PIC experts: How can I have a device trigger for a wakeup from suspend mode?
And indeed, the answer is Yes on the first question.
In the meantime, I found another link on the web that contains a Visual Studio C# implementation of a USB library including all the source files.
If you're interested, this is the link
This C# host implementation works as a charm. Without sending a command to the device, I get notified immediately if a button is pressed. Great!
It also proofs that my earlier device implementation based on the original MicroChip MLA, is 100% correct. I stress tested the implementation by sending a "toggle LED command" as fast as I could, and I reach 1000 commands/second. Again great!
I think that LibUsbDotNet isn't that perfect after all. As I wrote above, I get rather unstable communication (Win32Error). But with this implementation, I don't get a single error, even after running for half an hour # 1000 commands/second.
So for me, case closed.
I am creating a .Net Project on which it monitors a specific data of devices via Modbus communication. I created a form for each devices connected to it, and for each form I added atleast 4 server-based timers from System.Timers.timers class, these 4 timers are the one who manage the communication between devices. Now my question is, since each form corresponds to 1 device, and 1 form has 4 Timers which is running background, my concern is, what If I have multiple device to monitor? let say 50 devices? So it mean I need to run atleast 200 timers at my project right? Does a .net project can accomodate that amount of Timers?
There is only the limit of your hardware (CPU, RAM, ...). So, when using multiple timers, which have the same delay think about using one timer, but do all the desired actions in that one tick to decrease your RAM usage.
I'm doing a bit of research on Intel Pin. I'm looking to see if there is a way of attaching a Pin tool to an existing process using the Pin API.
I can see there is a way of running the pin executable on an already running process using pin.exe -pid <process_id> but I can't see anything in the pin documentation.
EDIT: As per a previous comment, I'm updating the question with an example.
The problem I'm trying to solve is instrumenting an injected process (this is for malware analysis).
If the process/binary I'm instrumenting creates a child process then pin can seamlessly attach itself to said child process. Wonderful!
If, however, the binary process/binary I'm instrumenting injects into another process (i.e. OpenProcess > VirtualAllocEx > WriteProcessMemory > CreateRemoteThread) then Pin will NOT attach to the injected process. I need to be able to tell pin to attach dynamically at runtime.
You'll have to implement something like that yourself - instrument the system calls and if you see an injection pattern, attach pin to the process.
I'm developing an embedded app, written in C, using a M16C/28 uC from Renesas.
The app manages two simple task:
RFID for detection and reading MIFARE tags. ( Using HW: Mf500 from NXP ). The uC handles whole FW implementation.
To deal with a RS485 frame protocol as slave. ( This app, have to be able to process RS485 frames every 10ms ).
The RFID implementation contains blocking code and the time response to detect a RFID tag is about 15ms. This causes RX reception buffer overflows on the RS485 processing.
My questions are as follows:
Is it normal to deal with such time responses in the RFID world?
Should I use a RTOS to preempt RFID task to meet RS485 frames requirements?
Should I use an external uC acting as host controller to release the load of the RFID manager uC?
Thanks in advance
To answer your questions:
Depends
You could use a RTOS.
You could use an additional uC.
Better options would be to:
Use DMA on serial communications.
Make the RFID code non blocking.
Do more in your serial interrupt.
The response time varies depending on the type of card/rfid that your are communicating with. I don't know the timings of Mifare RFIDs but 15 ms does not seem to be bad.
In your situation, you may have more requests coming from RS485 than you can handle on the RFID part. You can use queues or FIFOs to store the input requests so that you can treat them later on, according to the physical limitations of your system.
Using an RTOS can help but usually, they are not free. Plus, you may have to port it to your platform if it is not already supported. If all your firmware does is handling RS485 requests and communicating with the RFID, you should sort this out with interruptions to store the incoming commands and a loop to process them separately.
And for the second uC, it's like the RTOS. It can help but might not be the right solution in this scenario (you will have to manage 2 firmwares, a communication protocol or a FIFO between uCs, it will cost twice the price, ...).
My app communicates with a simple USB device as follows:
The app sends commands (2 or 3 bytes each) to the USB device by using WriteFile (kernel32.dll).
For each command that is send, the USB device sends a short response, which the PC receives using ReadFile (kernel32.dll).
Reading and writing is done asynchronously, using GetOverlappedResult to check the status of an operation.
Testing on 2 out of 3 PCs, the app and device function perfectly: all responses are received 100% reliably.
Under identical tests on the third PC, approximately 50% of the ReadFile requests do not return any data - the status remains as pending (ERROR_IO_INCOMPLETE) forever.
In other words, approximately for every 2 commands sent, one response is received.
Because the device functions perfectly with the other PCs, it lead me to believe that the problem might be occuring inside Windows, in the underlying code which is called by ReadFile (I presume some lower level USB driver code).
Question:
Please could you advise what debugging tool is most useful to investigate this? With my current knowledge, the internal workings of ReadFile are quite opaque.
The PC which is experiencing the issue is running Windows 8.0
You could try DebugView. Run as admin.
Go to "Capture", enable "Capture Kernel", enable "Enable Verbose Kernel Output".
This might help to investigate errors on Kernel level, if any occured.