First, I program for Vintage computer groups. What I write is specifically for MS-DOS and not windows, because that's what people are running. My current program is for later systems and not the 8086 line, so the plan was to use IRQ 8. This allows me to set the interrupt rate in binary values from 2 / second to 8192 / second (2, 4, 8, 16, etc...)
Only, for some reason, on the newer old systems (ok, that sounds weird,) it doesn't seem to be working. In emulation, and the 386 system I have access to, it works just fine, but on the P3 system I have (GA-6BXC MB w/P3 800 CPU,) it just doesn't work.
The code
setting up the interrupt
disable();
oldrtc = getvect(0x70); //Reads the vector for IRQ 8
settvect(0x70,countdown); //Sets the vector for
outportb(0x70,0x8a);
y = inportb(0x71) & 0xf0;
outportb(0x70,0x8a);
outportb(0x71,y | _MRATE_); //Adjustable value, set for 64 interrupts per second
outportb(0x70,0x8b);
y = inportb(0x71);
outportb(0x70,0x8b);
outportb(0x71,y | 0x40);
enable();
at the end of the interrupt
outportb(0x70,0x0c);
inportb(0x71); //Reading the C register resets the interrupt
outportb(0xa0,0x20); //Resets the PIC (turns interrupts back on)
outportb(0x20,0x20); //There are 2 PICs on AT machines and later
When closing program down
disable();
outportb(0x70,0x8b);
y = inportb(0x71);
outportb(0x70,0x8b);
outportb(0x71,y & 0xbf);
setvect(0x70,oldrtc);
enable();
I don't see anything in the code that can be causing the problem. But it just doesn't seem to make sense. While I don't completely trust the information, MSD "does" report IRQ 8 as the RTC Counter and says it is present and working just fine. Is it possible that later systems have moved the vector? Everything I find says that IRQ 8 is vector 0x70, but the interrupt never triggers on my Pentium III system. Is there some way to find if the Vectors have been changed?
It's been a LONG time since I've done any MS-DOS code and I don't think I ever worked with this particular interrupt (I'm pretty sure you can just read the memory location to fetch the time too, and IRQ0 can be used to trigger you at an interval too, so maybe that's better. Anyway, given my rustiness, forgive me for kinda link dumping.
http://wiki.osdev.org/Real_Time_Clock the bottom of that page has someone saying they've had problem on some machines too. RBIL suggests it might be a BIOS thing: http://www.ctyme.com/intr/rb-7797.htm
Without DOS, I'd just capture IRQ0 itself and remap all of them to my own interrupt numbers and change the timing as needed. I've done that somewhat recently! I think that's a bad idea on DOS though, this looks more recommended for that: http://www.ctyme.com/intr/rb-2443.htm
Anyway though, I betcha it has to do with the BIOS thing:
"Notes: Many BIOSes turn off the periodic interrupt in the INT 70h handler unless in an event wait (see INT 15/AH=83h,INT 15/AH=86h).. May be masked by setting bit 0 on I/O port A1h "
Related
I'm trying to write to the flash memory of STM32L4R5 in 'FLASH_TYPEPROGRAM_FAST' mode of the HAL_FLASH_Program().
The flash of the MCU is configured as Single Bank.
Writing to the flash only works when using 'FLASH_TYPEPROGRAM_DOUBLEWORD'. The flash reads as 0xFFFFFFFF when written in 'FLASH_TYPEPROGRAM_FAST' mode.
This is my test project:
// Page Erase Structure
static FLASH_EraseInitTypeDef EraseInitStruct;
// Page Erase Status
uint32_t eraseStatus;
// Data Buffer
uint64_t pDataBuf[32] =
{
0x1111111122222222, 0x3333333344444444,
0x5555555566666666, 0x7777777788888888,
0x12345678ABC12345, 0x23456789DEF01234,
0x34567890AAABBB12, 0x4567890FABCDDD34,
0x1111111122222222, 0x3333333344444444,
0x5555555566666666, 0x7777777788888888,
0x12345678ABC12345, 0x23456789DEF01234,
0x34567890AAABBB12, 0x4567890FABCDDD34,
0x1111111122222222, 0x3333333344444444,
0x5555555566666666, 0x7777777788888888,
0x12345678ABC12345, 0x23456789DEF01234,
0x34567890AAABBB12, 0x4567890FABCDDD34,
0x1111111122222222, 0x3333333344444444,
0x5555555566666666, 0x7777777788888888,
0x12345678ABC12345, 0x23456789DEF01234,
0x34567890AAABBB12, 0x4567890FABCDDD34
};
// Flash Page Start Address
uint32_t pageAddr = 0x081FE000;
// Fill Erase Init Structure
EraseInitStruct.TypeErase = FLASH_TYPEERASE_PAGES;
EraseInitStruct.Banks = FLASH_BANK_1;
EraseInitStruct.Page = 255;
EraseInitStruct.NbPages = 1;
// Unlocking the FLASH Control Register
HAL_FLASH_Unlock();
// Clear OPTVERR Bit Set on Virgin Samples
__HAL_FLASH_CLEAR_FLAG(FLASH_FLAG_OPTVERR);
// Erasing the Flash Page
HAL_FLASHEx_Erase(&EraseInitStruct, &Error);
#if 0
// Wriring a Doubled Word to Flash. pDataBuf[0] is the 64-bit Word
HAL_FLASH_Program(FLASH_TYPEPROGRAM_DOUBLEWORD, pageAddr, pDataBuf[0]);
#else
// Wriring 32 Double Words. pDataBuf is the Starting Address of the 64-bit Array
HAL_FLASH_Program(FLASH_TYPEPROGRAM_FAST_AND_LAST, pageAddr, pDataBuf);
#endif
// Locking the FLASH Control Register
HAL_FLASH_Lock();
Am I doing anything wrong?
Thank you,
Ivan
Document RM0932, Reference manual for STM32L4+, section FLASH. It covers reading and writing from/to flash, for both single-bank and double-bank configurations and different MCU models of this line. It seems, most differences are about reading from Flash (64-bit for dual bank, 128-bit for single bank). As for writing, page 128:
Flash is very picky about data width, and every STM32 has different data width for its flash, it seems. Very recently I stumbled upon one, which accepted only 16-bit writes and reads. This one likes double words. There is no universal function to read and write flash to any STM32, so it seems one of your commands doesn't respect this MCU's Flash data width rules. You can check if any error flags appear as per reference manual, although, as you can see, it doesn't say anything about trying to write 32-bit piece of data. I would expect that write to fail, but we can't make any conclusions about error flags from the screenshot provided. If you're curious enough, you can look at what data width every mode/function of yours utilizes and see what happens. 64-bit writes have to work.
Computer:
Processor: Intel Xeon Silver 4114 CPU # 2.19Ghz (2 processors)
Ram: 96 Gb 2666 Hz: 12 - 8 Gb sticks
OS: Windows 10
GPU: None
Hard drive: Samsung MZVLB512HAJQ-000H2 - 512GB M.2 PCIe NVMe
IDE:
Visual Studio 2019
I am including what I am doing in case it is relevant. I am running a visual studio code where I read data off a GSC PCI SIO4B Sync Card 256K. Using the API for this card (Documentation: http://www.generalstandards.com/downloads/GscApi.1.6.10.1.pdf) I read 150 bytes of data at a speed of 100Hz using the code below. That data is then being split into to the message structure my device. I can’t give info on the message structure but the data is then combined into the various words using a union and added to an integer array int Data[100];
Union Example:
union data_set{
unsigned int integer;
unsigned char input[2];
} word;
Example of how the data is read read:
PLX_PHYSICAL_MEM cpRxBuffer;
#define TEST_BUFFER_SIZE 0x400
//allocates memory for the buffer
cpRxBuffer.Size = TEST_BUFFER_SIZE;
status = GscAllocPhysicalMemory(BoardNum, &cpRxBuffer);
status = GscMapPhysicalMemory(BoardNum, &cpRxBuffer);
memset((unsigned char*)cpRxBuffer.UserAddr, 0xa5, sizeof(cpRxBuffer));
// start data reception:
status = GscSio4ChannelReceivePlxPhysData(BoardNum, iRxChannel, &cpRxBuffer, SetMaxBytes, &messageID);
// wait for Rx operation to complete
status = GscSio4ChannelWaitForTransfer(BoardNum, iRxChannel, 7000, messageID, &amount);
if (status)
{
// If we have an error, "bytesTransferred" will contain the number of bytes that we
// actually transmitted.
DisplayErrorMessage(status);
printf("\n\t%04X bytes out of %04X transferred", amount, SetMaxBytes);
}
My issue is that this code works fine and keeps up for around 5 minutes then randomly it stops being able to keep up and the FIFO (first in first out) register on the PCI card begins to fill up faster than the code can process the data. To me this seems like a memory leak issue since the code works fine for a long time, then starts to slow down when nothing has changed as all the code is doing it reading the data off the card. We used to save the data in a really large array but even after removing that we had the same issue.
I am unsure how to figure out exactly what is happening and I'm hopping for a way to determine if there is a memory leak and how to fix it if there is.
It being a data leak is only a guess though and it very well could be something else that is the problem so any out of the box suggestions for diagnosing the problem are also appreciated.
Similar to Paul's answer, but I like to strategically place two (or more) _CrtMemCheckpoint followed by _CrtMemDifference, to cut down the noise.
Memory leaks can be detected and reported on (in Debug builds) by calling the _CrtDumpMemoryLeaks function. When running under the debugger, this will tell you (in the output tab) how many allocations you have at the time that it is called and the file and line number that each was allocated from.
Call this right at the end of your program, after you (think you) have freed all the resources you use. Anything left over is a candidate for being a leak.
I have a question regarding buffering in between blocks in GNU Radio. I know that each block in GNU (including custom blocks) have buffers to store items that are going to be sent or received items. In my project, there is a certain sequence I have to maintain to synchronize events between blocks. I am using GNU radio on the Xilinx ZC706 FPGA platform with the FMCOMMS5.
In the GNU radio companion I created a custom block that controls a GPIO Output port on the board. In addition, I have an independent source block that is feeding information into the FMCOMMS GNU block. The sequence I am trying to maintain is that, in GNU radio, I first send data to the FMCOMMS block, second I want to make sure that the data got consumed by the FMCOMMS block (essentially by checking buffer), then finally I want to control the GPIO output.
From my observations, the source block buffer doesn’t seem to send the items until it’s full. This will cause a major issue in my project because this means that the GPIO data will be sent before or in parallel with sending the items to the other GNU blocks. That’s because I’m setting the GPIO value through direct access to its address in the ‘work’ function of my custom block.
I tried to use pc_output_buffers_full() in the ‘work’ function of my custom source in order to monitor the buffer, but I’m always getting 0.00. I’m not sure if it’s supposed to be used in custom blocks or if the ‘buffer’ in this case is something different from where the output items are stored. Here's a small code snippet which shows the problem:
char level_count = 0, level_val = 1;
vector<float> buff (1, 0.0000);
for(int i=0; i< noutput_items; i++)
{
if(level_count < 20 && i< noutput_items)
{
out[i] = gr_complex((float)level_val,0);
level_count++;
}
else if(i<noutput_items)
{
level_count = 0;
level_val ^=1;
out[i] = gr_complex((float)level_val,0);
}
buff = pc_output_buffers_full();
for (int n = 0; n < buff.size(); n++)
cout << fixed << setw(5) << setprecision(2) << setfill('0') << buff[n] << " ";
cout << "\n";
}
Is there a way to monitor the buffer so that I can determine when my first part of data bits have been sent? Or is there a way to make sure that the each single output item is being sent like a continuous stream to the next block(s)?
GNU Radio Companion version: 3.7.8
OS: Linaro 14.04 image running on the FPGA
Or is there a way to make sure that the each single output item is being sent like a continuous stream to the next block(s)?
Nope, that's not how GNU Radio works (at all!):
A while back I wrote an article that explains how GNU Radio deals with buffers, and what these actually are. While the in-memory architecture of GNU Radio buffers might be of lesser interest to you, let me quickly summarize the dynamics of it:
The buffers that (general_)work functions are called with behave for all that's practical like linearly addressable ring buffers. You get a random number of samples at once (restrictable to minimum numbers, multiples of numbers), and all that you not consume will be handed to you the next time work is called.
These buffers hence keep track of how much you've consumed, and thus, how much free space is in a buffer.
The input buffer a block sees is actually the output buffer of the "upstream" block in the flow graph.
GNU Radio's computation is backpressure-controlled: Any block's work method will immediately be called in an endless loop given that:
There's enough input for the block to do work,
There's enough output buffer space to write to.
Therefore, as soon as one block finishes its work call, the upstream block is informed that there's new free output space, thus typically leading to it running
That leads to high parallelity, since even adjacent blocks can run simultaneously without conflicting
This architecture favors large chunks of input items, especially for blocks that take a relative long time to computer: while the block is still working, its input buffer is already being filled with chunks of samples; when it's finished, chances are it's immediately called again with all the available input buffer being already filled with new samples.
This architecture is asynchronous: even if two blocks are "parallel" in your flow graph, there's no defined temporal relation between the numbers of items they produce.
I'm not even convinced switching GPIOs at times based on the speed computation in this completely non-deterministic timing data flow graph model is a good idea to start with. Maybe you'd rather want to calculate "timestamps" at which GPIOs should be switched, and send (timestamp, gpio state) command tuples to some entity in your FPGA that keeps absolute time? On the scale of radio propagation and high-rate signal processing, CPU timing is really inaccurate, and you should use the fact that you have an FPGA to actually implement deterministic timing, and use the software running on the CPU (i.e. GNU Radio) to determine when that should happen.
Is there a way to monitor the buffer so that I can determine when my first part of data bits have been sent?
Other than that, a method to asynchronously tell another another block that, yes, you've processed N samples, would be either to have a single block that just observes the outputs of both blocks that you want to synchronize and consumes an identical number of samples from both inputs, or to implement something using message passing. Again, my suspicion is that this is not a solution to your actual problem.
I have a device that outputs 64 bits of binary data at a rate of 1KHz. I am reading the device over USB via a 3rd party DLL, converting the binary data into a float, timestamping it, and writing to file.
I have the following setup at the moment:
int main(int argc, char* argv[])
{
unsigned char Message_Rx[64];
USHORT Bytes_Read=0;
std::ofstream out(argv[1]);
do
{
Result = Comms.USBRead(&Message_Rx[0],&Bytes_Read);
unsigned long now = getTickCount(start);
if(Result != 0)
{
uint16_t msb (Message_Rx[11] & 0xff) \\leftshited 8;
uint16_t lsb (Message_Rx[12] & 0xff);
uint16_t rate = msb | lsb;
char outstring[1024];
sprintf(outstring, "%d\t%.7f", now, (float)rate*0.03125);
out << outstring << "\n";
}
}while(!kbhit());
out.close();
}
(Sorry, formatting gets messed up with >> or <<).
This produces perfectly good results on my desktop. There doesn't appear to be any data missing and the timestamps are continuous and 1ms apart.
143379582 -0.5937500
143379583 -1.5312500
143379584 -1.6250000
143379585 -1.4062500
143379586 -1.1875000
143379587 -1.3437500
143379588 -1.3125000
143379589 -1.3125000
143379590 -1.1562500
But when I run this on the old laptop that I need to use I get timestamps that appear in blocks and it looks like there must be some data missing:
143379582 -0.5937500
143379582 -1.5312500
143379582 -1.6250000
143379582 -1.4062500
143379582 -1.1875000
143379593 -1.3437500
143379593 -1.3125000
143379593 -1.3125000
143379593 -1.1562500
Is there a way to achieve a speedup of my code so that I won't lose data?
To say this loud and clear: for any PC that is not a Intel 486SX, 64kb/s is a utmost laughable rate. Getting a few Mb/s over USB is very doable with small, Dollar-a-piece microcontrollers without any optimization.
Whatever goes wrong needs investigation much more than your code does.
I don't know the Comms library, but that's where I'd look for the place where time is spent.
Other than that, your printing stuff to the screen should take orders of magnitude more time than your processing, but still shouldn't be a problem. As mentioned, 1kS/s * 64 b/S is nothing for modern (read: last twenty years) PC hardware.
I recommend storing the raw data until the key is hit. After the key is pressed, output the data.
You want to remove formatting and output from high performance code areas.
Paraphrasing a song, There will be time enough for printing when the data's done.
Edit 1:
An array-based circular queue is a good data structure to hold the incoming data. This gives you the last N data samples.
Whenever you have issues with performance, your first step should be to profile the code to see what parts of it are taking up time.
However, for your code, I would say that the printing and string handling are unnecessary for the main loop. I would have a separate array of timestamps and within my main loop only acquire data.
After a key is hit, you no longer have timing restrictions and can deal with the somewhat expensive operation of file I/O and building up of the strings.
A final note is that your OS might be stealing CPU cycles from you. You may want to try to run your code with higher priorities to rule out scheduling.
With all that said, as was mentioned above, your data rate should be sustainable unless you're running on some really vintage hardware.
The intention of the program below is to periodically output a dataframe on serial. The period is defined by a timed interrupt, every second.
The code worked on Arduino IDE version 0022, but on 1.0 I can't get it working. When using the timer routine and maxFrameLength is set to 0x40 or higher, the controller locks up. When using 0x39 or lower, the program keeps running (indicated by the flashing LED).
What's going wrong here and why? Is it a bug? Am I doing something wrong?
I'm using http://code.google.com/p/arduino-timerone/downloads/detail?name=TimerOne-v9.zip for the timer routine on a Mega1280.
#include "TimerOne.h"
#define LED 13
#define maxFrameLength 0x40
boolean stateLED = true;
byte frame[ maxFrameLength ];
void sendFrame() {
digitalWrite( LED , stateLED );
stateLED = !stateLED;
Serial.write( frame, maxFrameLength ); // ptr + bytes to send
}
void setup() {
pinMode( LED , OUTPUT );
Timer1.initialize( 1000000 ); // initialize timer1 with 1 second period
Timer1.attachInterrupt( sendFrame );
Serial.begin( 9600 );
};
void loop() {
};
There are a number of issues that may or may not be causing a problem, but it should be fixed in any case. These comments are general in nature; I am not familiar with Arduino or its library specifically.
It is almost certainly inappropriate to issue a Serial.write() call in an interrupt handler (ISR). If the Serial object is interrupt driven, it will have an associated buffer. If that buffer is not large enough to take all the data, the function may block, which is a no no in an interrupt handler. Moreover, if the timer interrupt is a higher priority that the serial interrupt, you will cause a deadlock when Serial.write() blocks. 0x40 (64 bytes) seems like a likely buffer size for serial output, so that is likely the primary cause. If you can increase the buffer size that may make it work, but it remains a bad idea to perform potentially blocking operations in an ISR.
Even if serial output is polled rather than interrupt driven, your interrupt handler will take rather long, which is also a bad idea, but probably not the issue in this case, but at 9600,n,8,1, 64 characters will take 67 milliseconds to clear the transmit register.
stateLED and frame are shared variables (between interrupt and main contexts) and should therefore be declared volatile.
It is not shown in your fragment how and where frame is updated, but since the interrupt will occur asynchronously, any update to frame should be in a critical section - with at least the timer1 interrupt disabled.
Update
In the light of A.H.'s response I downloaded the source code and took a look. Serial is a static object of class HardwareSerial defined in \arduino-1.0\hardware\arduino\cores\arduino\hardwareSerial.cpp/.h. The transmit buffer length is indeed 64 bytes, and the HardwareSerial::write() function does "busy-wait" if the buffer is full. You will need to modify and re-build the source to extend the buffer or add a non-blocking version of write().
This is however certainly the cause of the lock-up - the buffer will never empty because the transmit interrupt cannot be serviced while the timer1 interrupt is running.
The release notes for 1.0 tell you:
Serial transmission is now asynchronous - that is, calls to
Serial.print(), etc. add data to an outgoing buffer which is transmitted
in the background. Also, the Serial.flush() command has been repurposed
to wait for outgoing data to be transmitted, rather than dropping
received incoming data.
Therefore your code worked before 1.0, because HardwareSerial::write(uint8_t) (which is the foundation for all output) had no buffer and returned only after the byte has been transmitted.
I find it astonishing, that the reference page for Serial does not mention this behaviour.