Im doing a dsp project and i want to take an anolog file and convert it to a digital output using a microconroller attached to a ADC on a dsp board. How would i program this in c?
Pretty much its as simple as that, atleast i think.
This is what i need.
Input --------- Output
Angolog --> Digital
Digital --> Anolog
You really need to clarify your question. Like what do you mean by analog file? File systems are binary from a programming perspective, sure the media is magnetic or other technologies and there is analog involved. An ADC goes from Analog to Digital, so it is an an analog input not a digital output.
ADC analog to digital converter, takes analog inputs to the device and converts them to digital so you can use them inside the chip, program, save to files, etc.
DAC digital to analog converter, takes digital values and converts them to analog outputs.
In both cases you need to look at the specific details for the chips and the board. From a programming perspective if nothing else you need to look into the details for the ADC and or DAC. Microcontrollers having an ADC is not uncommon, but you need to read up on how to get the ADC on that microcontroller to initiate a sample, how to know when the sample has completed and how to read the digital data once the sample has been taken. DACs are often external, sometimes serial, so you may have to bit bang spi or i2c or look into what hardware the microcontroller might have for speaking spi or i2c or if there is a dac in the microcontroller, how to use it (what registers to write, etc).
If you have a specific publicly available microcontroller board, for example an eval board, then that makes it much easier for folks here or elsewhere to show you where to look for the schematics, data sheets, etc. Otherwise, even knowing exactly which microcontroller and what I/O pins are used, would be helpful when asking such a question. There are probably lots of example programs out there that could be borrowed from. And it could be as simple as a few lines of C to an existing library, or as complicated as many lines of C with interrupt service routines, and possibly some assembler.
This is extremely dependent on your hardware and there's no information in the question that would enable a real answer.
In general, you should see the documentation for your system, especially the AD/DA parts. There should be good examples. If there's a particular problem, post a more specific question.
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I try to make a Bluetooth speaker with a microcontroller (Arduino, teensy... I don't have a defined model, because I'm considering the frequency)
My question is if I want to put a SD, for reading music stored, the problem is there are library only for ".wav" files, but I want to extend for ".mp3", ".m4a", ".aac" and other.
Exist any library for this? and if is not, How I can do it?
I need to decode an audio files, convert the data in bytes and send it to the DAC.
An example code in C++ will help me a lot, I can created a new library for this.
I don't want use modules, I want to try to do my own circuit.
Edit:
I gonna use a third party microcontroller compatible with Arduino, because I need more capacity for audio.
PDT: I don't know if I had to post this in Arduino o electrict defined, so I put in general.
The Arduino does not have sufficient resources to do this. An MP3 decoder needs plenty of memory and floating point support. The AVR processors used for Arduinos have neither of these.
The only way you are going to do this with a Arduino is if you use a module.
Teensy base on ARM microcontroller (Cortex-M3 & M4) come with FPU, have capacity for play videos. Teensy is a board compatible with arduino. With DAC and SD slot. Adafruit have a library for play .mp3 on this board.
Well .mp3 is enough for me, but in the future I want to learn how to decode other audio file formats.
I need to do some NON-STANDARD signal processing operations with an RFID-reader, so I'd like to know if it is possible to extract antenna's individual analog (actually digital samples right after ADC) input signal samples with Motorola FX7500 (if you know how this works on FX7400 or FX9500, please do tell, could be helpful). Samples would be processed in a JAVA-based host computer program.
What I've already tried:
Investigating Motorola's own RFID3 API's possibilities, it doesn't go deep enough to actually get in touch with input analog signal samples.
Using LLRP to its full extent, it doesn't allow analog signal sample access either. RFsurvey-functionality would have been helpful to some extent, but FX7500 doesn't support it either.
Accessing RFID-reader's linux terminal, trying to find the driver function(s), that could listen the input sample stream. If current input sample(s) could be extracted from the input stream, I could (in theory) make a script, that would save a few of those sample values in a txt-file in the host computer during a tag inventory round. My linux skills are kinda bad, hence I ask this question.
The only realistic way to solution seems to be via linux terminal, so if you folks have any ideas about that (where to look and what to do), please advise!
Contents of reader:
rfidadm#FX7500abcdef:/$ ls -1
apps
bin
dev
etc
home
include
lib
linuxrc
media
mnt
platform
proc
readerconfig
run
sbin
sys
tmp
usr
var
I cannot completely rule that out, but it's highly unlikely you can get the raw signal digitized; the devices you're looking at aren't really software defined radio devices, typically.
"speaking" RFID physically is a bit different from "usual" wireless communication: The reader doesn't only observe the energy transmitted from the tag, but more importantly the fluctuations of energy extracted from the near field of the reader's antenna coil. Hence, you don't actually have a baseband of RF bandpass signal, but hardware-specific modulations of transmitted (and inversely, antenna-reflected) energy. Demodulation is hence usually done in specialized hardware.
However, do not fret: It's totally possible to build a software defined RFID reader. There have been several approaches to that, but personally, I trust these based on Ettus USRPs and/or GNU Radio best. Look through the results IEEExplore gives you, eg. this search.
Most probably this is not possible with the Motorola readers. What you can do, is use one of the RFID chipsets available on the market: either the AMS RFID IC's, or the Impinj RFID IC's. As far as I know, both IC's support retrieving the digital samples that are received. They also have a development kit to test-drive the IC's.
I've been looking online for solutions on how to generate a simple beep with an DE2 Altera board using VHDL but I can not seem to find anything.
I've seen some things that are talking about Audio Codec but I haven't been able to get a firm grasp of what I would need to do with it.
Thanks a lot!
-Will
The "audio codec" is a separate chip (a Wolfson WM8731 in your case) which can turn information on digital form into analog information to be amplified/played through a standard sound system with amplifier/speaker/etc.
You'll need to find out how to interface to the audio codec chip from the FPGA (google a datasheet for the chip), and then send it the necessary information to generate you beep. Depending on how advanced the audio chip is, this task can vary rather much in complexity. As it's an educational board, you might be able to find people who've already done something similar, and then build on their experience.
If all you need is a simple beep though, you might also be able to create a simple circuit with a piezo-buzzer or similar yourself - that can be controlled without having to use an audio codec...
On a basic embedded systems speaker with a single line of output, wiggling the output as 0 or 1 in a for given periods produces sound.
I'd like to do something similar on a modern Linux desktop. A brief look-see of Portaudio, OpenAL, and ALSA suggests to me that most people do things at a considerable higher level. That's ok, but not what I'm looking for.
(I've never worked with sounds on Linux before, so if a tutorial exists, I'd love to see it).
Actually, it... kinda is. While you can generate the waveform yourself, you still need to use an API to queue it and send it to the audio hardware; there no longer even exists a sane way to twiddle the audio line directly. Plus you get cross-platform compatibility for free.
[...] embedded systems speaker with a single line of output, wiggling the output as 0 or 1 in a for given periods produces sound.
Sounds a lot like the old PC speaker. You might still find code for it in the Linux kernel.
I'd like to do something similar on a modern Linux desktop.
Then you need AFAIK a driver for ALSA. There you can find infos on how to write an ALSA driver. Use PWM to produce the sound.
Since there are many different sound cards and audio interfaces produced by different companies, there is no uniform way to have a low level access to them. With most sound I/O APIs what you need to do is to generate the PCM data and send that to the driver. That's pretty much the lowest level you can go.
But PCM data is very similar to the 0-1 approach you describe. It's just that you have the in-between options too. 0-1 is 1-bit audio. 8-, 16-, 24-bit audio is what you'll find on a modern sound card. There are also 32- and 64-bit float formats. But they're still similar.
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I want to start FPGA programming. I don't have any knowledge at all about how FPGAs work and such. I would like to get a development board, not too expensive, but it should have at least 40 I/O pins. Anything up to $300 is OK.
I decided that I want to program in Verilog. I am not sure about the following:
How will my compiled 'program' be stored on the chip? I would guess the chip has some kind of EEPROM to save my program, but from what I have read, it is apparently stored in RAM. I want my program to remain on the chip (or to be loaded somehow) every time it powers up.
Can I buy a separate FPGA chip (not a whole development board) for production? And if yes, how can I upload my program to the separate chip? Does it in some way connect to the development board?
I'd recommend the Digilent Basys board as an introduction. It only has 16 external I/O, but it already has RAM, USB, switches, buttons, LEDs, 7-segment displays, a VGA connector, and a PS/2 connector onboard - You're unlikely to find an FPGA with fewer than 40 I/O pins. If you want I/O for another project, use the Nexys instead - More peripherals than I care to list, and also has a high-speed Hirose 43-pin connector if you have a project which specifically needs about 40 connections.
Also, consider how you want to interface with your PC. Is your goal to make an embedded system, or to interface with a computer through a PCI/Ethernet/USB connection?
Yes, you can buy separate FPGA boards for production - There's a dizzying array of options, though - Digikey has 5,300 at this time. You do need some way to program the FPGA, and an onboard NVM chip that programs the FPGA on startup is a popular option. However, you should start with a development board that's well supported and already has a programmer, toolchain and simulator available before you get too far into designing your board or worrying about how to save your program onto the chip. Those are good things to know, but they're not what you want to worry about right now. Good luck!
The whole point of using an FPGA is that your "program" is actually a circuit, not RAM. There are physical logic components that are configured when you write the bitstream to the FPGA. This is why they can run so much faster for specialized applications--you are basically making custom hardware.
Xilinx is one of the main FPGA manufacturers. Try their website. Check out the Boards & Kits section.
Try reading more about the technology before you get ahead of yourself. You will need a strong understanding of how FPGAs work before you can program them effectively. Wikipedia is a great place to start.
In Xilinx FPGA terminology the "program" is called bitstream. There are some FPGAs that have embedded flash to store the bitstream (e.g. Spartan 3AN). Most of the FPGAs require some external bitstream storage. Here is a configuration guide on how to configure an FPGA.
Yes you can. There are multiple ways to do configuration. Most of them require some external circuitry.
Check out Actels's new Smart Fusion FPGA. Its has a FPGA fabric of course, with a hard ARM MCU with a good analog end (DAC, ADC etc).
The Eval board is only 100$
http://www.actel.com/products/hardware/devkits_boards/smartfusion_eval.aspx
And all the software you need to get up and running if free.