I'm writing a software synth in Linux using libasound. I want to control it with a MIDI keyboard.
I have some working code using snd_seq_open() and snd_seq_event_input() but it only creates a virtual MIDI port. I have to go to the commandline and type "aconnect 20 128" to route the MIDI data to my app.
How can I get my code to either set up the connection by itself or connect directly to the MIDI hardware?
You have to create the connection with a function like snd_seq_connect_from().
See, for example, the aseqdump source code.
Related
AudioKit 4.9. I would like to receive MIDI events from the new AKSequencer, handle them and send the handled data to an external gear connected to a midi port of an audio interface like I can do with AKMIDICallbackInstrument set to an output of AKAppleSequencer. Investigating the source code I've figured out that there are two ways to receive MIDI from AKSequencerEngineDSPKernel (an internal sequencer in AKSequencer) : in AudioUnit and via MIDIEndpoint. I couldn't find any AudioUnit alternative for AKMIDICallbackInstrument, thus I wonder if there is any way to pass a value to midiEndpoint of AKSequencerEngineDSPKernel to correspond the AKMIDICallbackInstrumen.midiIn? It's possible that I missed something, please explain a better way to solve this problem.
So I took it upon myself to learn all about the FPGA this semester. To test my skills, I picked up a project to encrypt and decrypt files using a FPGA implementation of the age old AES. Now implementation of AES using Verilog has been done umpteen times and for my reference I used the code at http://opencores.org/project,systemcaes. What I wish to do is use the Verilog file handling functions to read a small file, use it as input to the encryption block on the FPGA, and save the encrypted file back on the computer. I am aware that this can be done on the testbench(though I have not attempted it, I am sure it can be done). But how do I do the same when I implement the code on the FPGA board? Is there a way to select the file to be encrypted/decrypted and pass it onto the board? Is it even possible?
Sorry if I come across as a noobie, its my first time in the world of FPGAs. Thanks in advance everyone!
You need to understand that the FPGA will only take a description of the hardware that you are going to build. It is not like a programming language.
So if you want to load data into a memory on the FPGA you need a way to move the data from you PC into the FPGA. The easiest way is to implement an UART on the FPGA so you can communicate with a serial port on your PC. Then you load data from some terminal program on your PC into the FPGA.
Then you can use the serial port to read the data back to your PC.
This of course require you to have implemented the hardware needed to read and write things to and from a memory in your FPGA.
It might also be that you can stream data through the FPGA. But then I think I would use two serial ports.
Verilog RTL does not have a concept of a file system, you would need the FPGA 'driver' to break the file down and send it over byte by byte or load it into a memory for the program on the FPGA to read.
I am not experienced with FPGAs, my under standing is that you synthesis the design and stream it into the FPGA. I thought that you might have still had some connectivity to the device where you were able to stream data to it. In the same way I think you can control the Arduino over USB.
How do you plan on getting the data back out of the FPGA? Do your tools allow you access to send and load data?
I am using STM32F205RGT6 Cortex-M3 microcontroller and coding with IAR Embedded Workbench.
I plan to keep the microcontroller in a power saving mode most of the time except when an external component tries to either communicate via SPI (the STM32 microcontroller is meant to be a SP slave) or via USB.
One external compinent is connected via SPI (PB12-15) and PC is connected via USB (PA11-12).
The communication works fine - I have tested both the SPI as well as USB.
I figured that once I am done setting up SPI and USB I will call a power saving function and add the same function call at the end of interrupt service routines. I have found PWR_EnterSTANDBYMode and PWR_EnterSTOPMode (in stm32f2xx_pwr.h) both of which I tried using.
However with such arrangement I cannot establish any communication (SPI or USB) with the microcontroller.
Is there something extra that needs to be configured (for example which pins should wake the microcontroller up)?
Am I using wrong function? Or wrong header file?
Can you point me to an example resembling such case (I could not find anything similar on ST's website)?
Any constructive feedback would be welcome.
In the mean time I found the application note AN3430 (http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/APPLICATION_NOTE/DM00033348.pdf) which is somehow more digestible (only 38 pages) which gives an excellent overview on power saving in the microcontroller.
Since I don't have access to PA0-WKUP (the wake-up pin) I had to discard using stand-by. Seems that just a simple sleep mode in main loop - by calling __WMI(); - should lower current consumption enough in my case. I might consider stop mode if sleep mode isn't enough but I will have read fragments of datasheet on configuration of EXTI registers that the application notepoints to.
How can i connect a windows phone 7 device with a WiFi-enabled micro controller. Should i use socket programming?? If yes then how?? I actually want to send a text file or a text message to the micro controller using WI-FI??
Your question is a bit vague. Are you trying to write a app that enables you to send a text file/message?
or are you trying to accomplish this by connecting to the microcontroller with the default connection your phone provides.
If you want to write your own app, you can do this by using a windows socket function. Have you looked into the standard code examples windows provides? They provide good examples about the basis of windows phone wifi connectivity
in example:
Example 1
Example 2
Edit:
You should take a look at this example.
Example
In this microsoft example, they make the game tic tac too between two windows phones. For your cause, you can read the data form file. Temporarly store it in an array. And send it over wifi. if you customize the example to fit your needs, so in steps:
Declare a socket (with the right ip adresses, ports etc)
Read file
Store in array
Send array by the wifi (using your previously declared socket)
And then on the microcontroller, you need some way to filter your data out of the incomming wifi buffer. I looked into one of my older projects where i did something like this. But i couldn't find it anymore. So i must have deleted it at some point "sorry :( " i you can work this out using the example
I would like to make a simple VST plugin that does this :
analyze an audio stream (volume, beat, etc...)
has triggers on the analyzer's output (e.g. do something when volume > threshold)
generate MIDI events based on the triggers
This is to be able to chain plugins, even if they are not designed for it. For example I could control the gain of a compressor with the envelope of an audio stream, simply by connecting the MIDI OUT of my plugin to the MIDI IN of the compressor's gain button.
The problem is I don't know how to do this. Is there support for direct MIDI connections like this in VSTs ? Or maybe I need some sort of "virtual midi device" for interconnects ?
Your hunch here is probably correct; this task will be easier to accomplish by writing a virtual MIDI device instead of a VST plugin. It is possible to send MIDI events to a sequencer using the sendVstEventsToHost() call, but the problem is that the documentation never specifies how the host is required to react to these events. Many hosts simply ignore them, and I certainly can't think of one which allows easy routing from a plugin to a MIDI channel (maybe plogue bidule?).
You might be able to accomplish this with Audio Units with the kAudioUnitType_Generator plugin type... though I've never written such a plugin, my impression was that this is what you'd use to generate MIDI to the host. But again, the problem here is that I'm not sure how the host would allow you to route audio to the plugin and accept MIDI from it.
At any rate, your idea implemented as a plugin will be the most difficult to implement when you want to standardize its behavior for the most widely used sequencers. I think that a far easier way to accomplish what you want is to create a virtual MIDI device, as you'd thought of already, and then use rewire to route an input signal to your program.
Edit: Here's some resources on writing MIDI drivers for various systems:
Audio device driver programming in OS X
Windows MIDI driver API guide
VST plugins do not support direct midi connections, they can only have midi in/out ports.
It is still possible to do it though, you just need a host that supports routing midi from one plugin to another. Modular hosts such as EnergyXT, Bidule, AudioMulch and Console excel here. They all allow audio and midi signals to be routed freely (except no feedback paths). But it also may be possible in hosts with more 'traditional' mixer style vst racks. (For example, AFAIK Reaper will forward any midi from one plugin to the next.)
If you want to build your plugin in .NET take a look at VST.NET