Help with odd problem

[Nils Roos]

Update: it finished succesfully.

There is one little gotcha though - the Makefiles are not aware that nginx depends on sources in "ngx_ext_modules". So if you change some code in that folder and make the build/sbin/nginx target again, it will not recompile the changed code.

I got it to rebuild with the following:

Code: Select all

make -C Bazaar/nginx clean
rm build/sbin/nginx
make build/sbin/nginx

With the previously built RAMdisk contents intact it takes less than a minute.

[erikgroving]

Hey again,
so I'm still in the process of getting that rebuilt. I had been trying to build from windows and haven't gotten the 64 bit ubuntu set up on the virtual machine, plus the 6.3 gb download of vivado 13.3 will be fun

Thanks for updating on that, knowing that it can build that way is a big relief. I didn't see you had replied until now, the sneaky page 2 got me.

But, I do have another question. I implemented a slow i2c controller using a separate i2c DA converter. The hardware is fine so that's not a problem, and won't ask any questions regarding other hardware, and the update rate is fine, (my dac_write C function is updating at 8,533 write/second, which is fine for what I want), the issue is the speed at which the fpga fabric is giving me data. My current method of accessing channel data is g_osc_fpga_cha_mem[g_osc_fpga_reg_mem->wr_ptr_cur], however, I only get a new value ever 0.025 seconds or so, (around a 40 Hz update, so can't really resolve 10 Hz signals, around 4-5 points per period, so you can see what it is but it's not smooth). SO what I want to know, is there any way I could communicate the current value of the adc input(and later the value of my internal FPGA signals, current adc value is for testing purposes) into the shared memory any faster? If not then I will need to use a different input source for my signal (perhaps using the spi interface for input?). I know the oscilloscope application uses a buffer to make the curve look smooth, but I don't think reading the entire buffer every time I look for a signal will work? Especially since the update rates of the buffer and my function wouldn't be the same. Unless there's a way to keep track of when it updates, but waiting for a the whole buffer to fill up adds a delay to my control. Any advice?

[erikgroving]

Thinking about it, I think it's actually unavoidable, memory latency is memory latency. Meh, that's fine!

[erikgroving]

It built for about an hour and then I got this message:

make[1]: Entering directory `/home/labuser/Desktop/RedPitaya/Bazaar/nginx'
strip nginx-1.5.3/objs/nginx
strip: Unable to recognise the format of the input file `nginx-1.5.3/objs/nginx'
make[1]: *** [install] Error 1

Upon entering the directory and typing file nginx, the following is displayed

nginx: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.16, not stripped

WELL I'LL BE.
After much headscratching and fruitless effort, the nginx server has somehow compiled. Thanks for everything Nils and I'll post again if my original aspiration of displaying multiple signals (dac out, spectrum) on one web app succeeds!
Have a good weekend

[Nils Roos]

Good to hear that you got it to compile in the end, because I couldn't think of a likely cause for your problems.

I am quite surprised about the 0.025s that you reported, it shouldn't have such a high latency, but I can't really look into it at the moment, so if it's not a pressing issue for you, I'll let it rest.

[erikgroving]

Latency came from the zoom of the scope in the web app. The slow trigger in the app made my update rate low. Zooming out all the way gave me the good update rate. If I change a few lines, I should be able to get my value regardless of the trigger. This gives me updates rates of about 8 kHz(which is perfect) for my PID, I think it could be even faster if the i2c bus was faster, but seeing that I only need 100 Hz update rate at max for my application my slow pid is more than fine now.

Also update with the server: everything is working now. nginx.conf needed to be changed manually(it's not changed by making the server) to increase the indices of datasets but nginx is fairly easy to configure so that was not too hard. Other than that it was just a matter of copying in the makefile built nginx and everything was good to go. I now have access to all the signals I wanted in the app .

No more problems on my end, for now!