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by sheroy
Mon Jul 11, 2016 8:43 am
Forum: C/C++
Topic: Delays writing CSV files
Replies: 5
Views: 961

Re: Delays writing CSV files

see if fclose helps
by sheroy
Sun May 22, 2016 5:59 pm
Forum: C/C++
Topic: .wav file: play from a C/C++ program (Raspbian)
Replies: 33
Views: 7696

Re: .wav file: play from a C/C++ program (Raspbian)

To read a wav file you may refer to http://soundfile.sapp.org/doc/WaveFormat/ for the file format and how to read, you may use pread. use timing (from time.h) to read the sample at the right time and put out a voltage onto the DAC which a linear function of the sample read. Beware for data in 2's co...
by sheroy
Tue Apr 19, 2016 4:52 pm
Forum: C/C++
Topic: i2c/spi DMA in c++
Replies: 4
Views: 1565

Re: i2c/spi DMA in c++

you may want to look at https://github.com/notro/spi-bcm2708/bl ... -bcm2708.c of how to setup DMA and also refer to the 2835 peripheral datasheet.
by sheroy
Fri May 22, 2015 7:22 am
Forum: Bare metal, Assembly language
Topic: STICKY: Bare Metal resources
Replies: 26
Views: 104663

Re: bare metal resources

One more bare metal development link in c

This is a bit higher by using c but essentially instead of writing in assembly one can write in c

http://www.valvers.com/open-software/ra ... g-in-cpt1/
by sheroy
Sun Jan 04, 2015 6:56 pm
Forum: Other projects
Topic: Sample Multiple ADC's at the same time
Replies: 10
Views: 1616

Re: Sample Multiple ADC's at the same time

I found a chip that may fit my needs it is the LTC1407A...although a bit expensive but will be worth it. Any other suggestions before i buy it?

Now have to get the PI's SPI working faster.
by sheroy
Sat Jan 03, 2015 6:48 pm
Forum: Other projects
Topic: Sample Multiple ADC's at the same time
Replies: 10
Views: 1616

Re: Sample Multiple ADC's at the same time

Are you using the Linux SPI driver? I'd be interested to know how you are getting the number of SPI transactions per second which 500 ksps per second suggests. No I'm not using the Linux SPI driver. The code is written in C for accessing the ARM peripherals directly. To get a birds eye view and to ...
by sheroy
Sat Jan 03, 2015 6:22 pm
Forum: Other projects
Topic: Sample Multiple ADC's at the same time
Replies: 10
Views: 1616

Re: Sample Multiple ADC's at the same time

Could you clarify what you mean by 500 ksps. I ignored it as it seems like a typo. What software are you using to get 500 thousand samples per second? I assumed you were talking about SPI clock speed of 500 thousand bits per second. It is 500 thousand samples per second. I have written a c code to ...
by sheroy
Sat Jan 03, 2015 6:02 pm
Forum: Other projects
Topic: Sample Multiple ADC's at the same time
Replies: 10
Views: 1616

Re: Sample Multiple ADC's at the same time

Perhaps something like http://www.raspberrypi.org/forums/viewtopic.php?f=44&t=71089 will meet your needs. This may be one option but have to yet try out, but as i see bit banging may be slow and increase CPU load as i see it now. Also i do not know if i will be able to achieve > 500 ksps @ 12 bit.
by sheroy
Sat Jan 03, 2015 5:43 pm
Forum: Other projects
Topic: Sample Multiple ADC's at the same time
Replies: 10
Views: 1616

Sample Multiple ADC's at the same time

How does one sample multiple ADC at the same time? Requirements- one of the ADC's are on the SPI bus(allows me to achieve high sampling rates, right now about 500 ksps @ 12bits). I need to have another ADC that samples another signal but the sample is taken at the same time which is decided by the S...
by sheroy
Wed Nov 19, 2014 5:32 am
Forum: Other projects
Topic: Raspberry PI based RF spectrum analyzer
Replies: 4
Views: 8096

Re: Raspberry PI based RF spectrum analyzer

Hi! I'm working on an CATV level meter and I used an old Philips tuner UV1316. I want to switch to the new TDA18250 tuner but I can't find a full datasheet about it. Have you? P.S. nice toy rasperberry Hi, I have also not found the complete data sheet you may also try google on TDA18218 which has s...
by sheroy
Tue Nov 18, 2014 3:26 am
Forum: Other projects
Topic: [solved]Can not run GPU FFT in a loop
Replies: 6
Views: 2724

Re: Can not run GPU FFT in a loop

Thanks Daniel, It works i was missing the mbox_close(mb) the the function after gpu_fft_release().
by sheroy
Mon Nov 17, 2014 4:57 pm
Forum: Other projects
Topic: [solved]Can not run GPU FFT in a loop
Replies: 6
Views: 2724

[solved]Can not run GPU FFT in a loop

I am currently working on a TV tuner based spectrum analyzer, more on http://www.raspberrypi.org/forums/viewtopic.php?f=41&t=47188 As mentioned in the post i am not yet able to get the gpu_fft code to be able to run in an infinite loop by calling the below functions in sequence mbox_open(); gpu_fft_...
by sheroy
Fri Oct 31, 2014 5:34 pm
Forum: Other projects
Topic: Raspberry PI based RF spectrum analyzer
Replies: 4
Views: 8096

Re: Raspberry PI based RF spectrum analyzer

The progress report so far. I have currently scrapped out the idea of using an SA602 as the front end. What I currently use is a TV tuner (I2C interface) that has been scraped out of a set top box. It is supposed to give a tuning range from 40MHz to about 1 GHz. The IF output can have an bandwidth u...
by sheroy
Sat Sep 06, 2014 5:58 am
Forum: Troubleshooting
Topic: [i think solved] Failure of my first series of the RPi 256Mb
Replies: 7
Views: 1221

Re: [i think solved] Failure of my first series of the RPi 2

ghans wrote:That's interesing. Can you post a picture ?

ghans

here is the picture of the RAM chip after the process.
20140906_111626_resized2.jpg
hot solder and hot iron moved across the RAM chip....(read the posts above for a more accurate account.)
20140906_111626_resized2.jpg (56.46 KiB) Viewed 862 times
by the way.. the pi is yet up...about 25 days...
by sheroy
Sat Aug 30, 2014 6:28 am
Forum: Troubleshooting
Topic: [i think solved] Failure of my first series of the RPi 256Mb
Replies: 7
Views: 1221

Re: Failure of my first series of the Raspberry Pi 256Mb ver

Yes, I think I fixed my Pi. but not quite so by dumping it into an oven or by using a hot air gun. Right now it has been stable for about 19 days. it was rebooted once by mistake. but I did not see the problem crop up. So what I did was start the pi use earphones to play some music(it was stable in ...
by sheroy
Sat Aug 02, 2014 8:35 pm
Forum: Troubleshooting
Topic: [i think solved] Failure of my first series of the RPi 256Mb
Replies: 7
Views: 1221

[i think solved] Failure of my first series of the RPi 256Mb

A problem with my very first Raspberry Pi B 256Mb popped up a few months ago. I am not yet able to figure out a solution. Symptoms - HDMI output goes blank, Network goes blank(with the lights on/off)...can not SSH...random flickering of memory access light stops. The pi fails within a few minutes(~5...
by sheroy
Sun Jul 06, 2014 4:30 pm
Forum: Troubleshooting
Topic: Pi shuts down soon after powering up at random points
Replies: 88
Views: 27730

Re: Pi shuts down soon after powering up at random points

I have also been having the same problem but this problem has just started recently on my 256Mb Pi which was running fine some time ago(for a few months), with a particular power supply and network connection. I have verified the pi turns off completely as I loose the network connection and the HDMI...
by sheroy
Wed May 28, 2014 12:25 pm
Forum: Troubleshooting
Topic: Polyfuse: The Pi suddenly dies when running
Replies: 5
Views: 913

Re: Polyfuse: The Pi suddenly dies when running

Next I tested the voltages, they were ~4.84V when it failed. The voltage on an average stayed near the value of 4.84V. So what I did was to short the input polyfuse and left the pi on, upto now ~3days it has not had a problem. also the voltage is close to ~4.96V. 4.84v shouldn't be too low - 4.75v ...
by sheroy
Wed May 28, 2014 8:25 am
Forum: Troubleshooting
Topic: Polyfuse: The Pi suddenly dies when running
Replies: 5
Views: 913

Re: Polyfuse: The Pi suddenly dies when running

fruitoftheloom wrote:I would say get a better quality Power Supply, the Polyfuse is there for a reason......
By the way it is the power supply from the RS site... I have been using it for months. (5V 1A)
by sheroy
Wed May 28, 2014 8:12 am
Forum: Troubleshooting
Topic: Polyfuse: The Pi suddenly dies when running
Replies: 5
Views: 913

Polyfuse: The Pi suddenly dies when running

My model B 256 Mb version has been lying on for a few months, It suddenly started failing and was not able to figure out. Everytime after I reformatted the card and restarted, the pi worked fine for a few days. But what was happening that the Pi during this time was not powered and thus it worked af...
by sheroy
Sat Jun 15, 2013 4:33 pm
Forum: Other projects
Topic: Raspberry PI based RF spectrum analyzer
Replies: 4
Views: 8096

Raspberry PI based RF spectrum analyzer

I am in progress of making a Raspberry pi based RF spectrum analyser The basic components are a direct digital synthesizer(DDS currently using AD9850), an RF mixer(like SA602) and an ADC like MCP3021. The basic operation is that the RF(say from an antenna with a preamp) is mixed with the time varyin...
by sheroy
Fri Jun 14, 2013 6:01 pm
Forum: C/C++
Topic: Read an MCP3021 using c
Replies: 0
Views: 1697

Read an MCP3021 using c

I am not able to figure out how to read the MCP3021 ADC from microchip.. I have not been able to use i2ctools for the above, which I would also like to figure out. mainly I need a c program to do the same. current state- device address is 0x4d as detected via i2c detect but when I do an i2cdump I ge...

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