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by mhelin
Fri Apr 13, 2018 1:20 pm
Forum: Graphics, sound and multimedia
Topic: 24-bit/192kHz Audio Over HDMI
Replies: 8
Views: 8056

Re: 24-bit/192kHz Audio Over HDMI

How is this today? Can 24 bit/192kHz audio played using ALSA over HDMI now?
by mhelin
Mon Mar 27, 2017 8:26 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Multiple I2S input
Replies: 29
Views: 21566

Re: Multiple I2S input

Good to know someone has succeeded with this hack, congrats to flatmax! Anyway, one thing that keeps me away from multichannel PI I2S/GPIO route is the fear that for some reason the BCM internal FIFO's loose sync (overflow) and as a result the channels will be shifted. In practice this could mean th...
by mhelin
Mon Mar 13, 2017 8:48 pm
Forum: Graphics, sound and multimedia
Topic: Modifying I2S output
Replies: 1
Views: 505

Re: Modifying I2S output

Just use YM3414 between Pi and DAC's. You need different clock signals, and the data format for YM3414 is right justified 16-bits.
by mhelin
Mon Feb 06, 2017 6:33 pm
Forum: Graphics, sound and multimedia
Topic: There is a Pi audio revolution and it wont be televised
Replies: 2
Views: 891

Re: There is a Pi audio revolution and it wont be televised

Mind letting us know how the protocol conversion works, how the I2S frames are handled by the FPGA? It would be nice if there were some kind of standard for marking the single I2S frames for multichannel mapping. You could either not mark anything and rely on continuum (but then if you miss a sample...
by mhelin
Sun Feb 05, 2017 12:04 pm
Forum: Advanced users
Topic: Pi 3 Studio DAW
Replies: 2
Views: 8222

Re: Pi 3 Studio DAW

Tracktion Waveform will be available for RPi (guess with Biotek synts):

https://www.youtube.com/watch?v=0c-eB2EwSAo
by mhelin
Thu Mar 31, 2016 6:01 am
Forum: General discussion
Topic: Which OS for Raspberry Pi 3?
Replies: 2
Views: 668

Re: Which OS for Raspberry Pi 3?

Try OSMC which got Kodi front-end.

http://kodi.wiki/view/OSMC
by mhelin
Wed Mar 30, 2016 10:48 am
Forum: Graphics programming
Topic: Stereo 3D using Bluetooth LE on RPi 3
Replies: 2
Views: 1358

Stereo 3D using Bluetooth LE on RPi 3

Is it possible to sync the GPU / HDMI to external "Full HD 3D" glasses to make it possible send 3D image possibly to any display device (also some VR glasses) supporting something like 120 Hz frame rate? I think these specs specify the used protocol (which is partly optional): https://www.bluetooth....
by mhelin
Tue Mar 08, 2016 1:22 pm
Forum: General discussion
Topic: The Raspberry Pi 3 Model B Q&A thread
Replies: 457
Views: 184288

Re: The Raspberry Pi 3 Model B Q&A thread

What about i2c clock streching issue ont the pi3? VideoCore is unchanged on Pi3 and that is where the I2C peripheral is, so no change in behaviour. Are the peripherals in VideoCore defined by software? If so then please consider implementing the TDM multichannel format for the PCM/I2S block as well.
by mhelin
Tue Oct 13, 2015 8:45 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Multiple I2S input
Replies: 29
Views: 21566

Re: Multiple I2S input

Regarding TDM one option would be to use a mode with CLKM = 1 , FSM = 0 (see the BCM2835 ARM Peripherals datasheet, MODE_A registers). Set the PCM to output and input data using two channels. Connect the 12.2880 MHz clock to PCM/I2S bitclock, and set the frame length for 32 bits: FRXP = FTXP = 0 for...
by mhelin
Wed Sep 16, 2015 7:05 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: TDM (TIME-DIVISION MULTIPLEXED) mode
Replies: 2
Views: 2258

Re: TDM (TIME-DIVISION MULTIPLEXED) mode

It might be possible. You have to generate the TDM frame sync from I2S/PCM (left justified) word clock. It's simple using a 74HC74 (one half of it or two in series). You have to reset the flip-flop (using a GPIO port) just when playback or record is triggered (in ALSA "trigger" callback in driver), ...
by mhelin
Thu Aug 27, 2015 4:23 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 868
Views: 368018

Re: I2S sound: Anyone got it running? (answer is yes!)

Nevermind, got it working. The normal preallocation doesn't seem to be working on RPi. With the "normal" I mean the one most often used: ret = snd_pcm_lib_preallocate_pages(substream, SNDRV_DMA_TYPE_CONTINUOUS, snd_dma_continuous_data(GFP_KERNEL), 16*4096,16*4096); (or snd_pcm_lib_preallocate_pages_...
by mhelin
Thu Aug 27, 2015 4:17 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 868
Views: 368018

Re: I2S sound: Anyone got it running? (answer is yes!)

I have been playing with the philpoole's Pi I2S driver (https://github.com/philpoole/snd_pi_i2s/blob/master/snd_pcm_pi_i2s.c), trying to make it use DMA (just for learning the ALSA, the ASoC driver works perfectly). However, I can't get it produce anything but the sound of a broken CD-player. It see...
by mhelin
Tue Feb 24, 2015 8:29 pm
Forum: HATs and other add-ons
Topic: CY8CKIT-044 PSoC® 4 M-Series Pioneer Kit
Replies: 1
Views: 614

CY8CKIT-044 PSoC® 4 M-Series Pioneer Kit

http://www.cypress.com/?rID=108008

Oddly it's got only the old 26-pin header for Raspberry Pi even though the product is all new.
by mhelin
Sun Feb 22, 2015 11:17 am
Forum: Raspbian
Topic: Windows XP on RPi2 for just one app
Replies: 12
Views: 3112

Re: Windows XP on RPi2 for just one app

If you cannot afford buying new Windows workstations check those Win 8.1 Intel Atom Mini PC's/Set Top Boxes (STB) first. For an example Pipo X7: http://www.aliexpress.com/store/product/PIPO-X7-Windows-8-1-with-Bing-OS-TV-Box-Smart-Mini-PC-Intel-Atom-Z3736F/323423_32263167112.html http://www.alibaba....
by mhelin
Sun Feb 22, 2015 11:10 am
Forum: Off topic discussion
Topic: RPiSoC Development Board Based on Cypress PSoC 5LP
Replies: 4
Views: 1576

Re: RPiSoC Development Board Based on Cypress PSoC 5LP

Too bad they didn't succeed with the Kickstarter, however, they have a new design coming through Kickstarter so they haven't given up which is good.

http://www.embeditelectronics.com/blog/ ... n-schools/
by mhelin
Wed Feb 11, 2015 3:49 pm
Forum: Troubleshooting
Topic: RPi 2 Model B Locking Up
Replies: 37
Views: 13885

Re: RPi 2 Model B Locking Up

Another cable solved the problem. Samsung U6 cable confirmed working.
by mhelin
Wed Feb 11, 2015 7:27 am
Forum: Troubleshooting
Topic: RPi 2 Model B Locking Up
Replies: 37
Views: 13885

Re: RPi 2 Model B Locking Up

I'm able to run without any problems Jessie with x-windows and XFCE installed on top of the distro @ http://sjoerd.luon.net/posts/2015/02/debian-jessie-on-rpi2/ but for some reason with the official (raspberrypi.org/downloads version 2015-01-31) Raspbian I'm getting kernel panic quite soon (without ...
by mhelin
Fri Mar 21, 2014 7:04 am
Forum: Graphics, sound and multimedia
Topic: Wolfson Pi Audio Card
Replies: 6
Views: 4568

Re: Wolfson Pi Audio Card

Anyone got the Wolfson card yet? They have patches for the drivers online.
by mhelin
Wed Mar 12, 2014 7:52 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 868
Views: 368018

Re: I2S: Anyone got it running? (answer is yes!)

Anyone got the Wolfson Audio Card yet?
http://www.element14.com/community/comm ... wolfson_pi

The drivers seem to be heavily patched, see http://downloads.element14.com/wolfson/ ... nAudioCard
by mhelin
Wed Mar 12, 2014 1:04 pm
Forum: Graphics, sound and multimedia
Topic: Analog audio acquisition
Replies: 2
Views: 1279

Re: Analog audio acquisition

You might want to try the Wolfson Audio Card:
http://www.element14.com/community/comm ... ry-wolfson

Funny the price is expressed as 25€ but the real price in my country is 44,64€. That's really bad marketing.
by mhelin
Thu Feb 27, 2014 8:03 pm
Forum: General discussion
Topic: Are ARM based computers the future?
Replies: 77
Views: 11097

Re: Are ARM based computers the future?

This CISC vs. RISC doesn't have much to do with the power consumption. RISC is hardwired controlled where CISC use microcode to implement the more complex instruction set. So CISC is kind of wrapper of multiple RISC instructions. Regarding power comsumption only the needed power/gate/speed is what m...
by mhelin
Mon Feb 24, 2014 12:46 pm
Forum: General discussion
Topic: RaspBerry Pi(e) Model C (imaginations & wants)
Replies: 431
Views: 142959

Re: RaspBerry Pi(e) Model C (imaginations & wants)

Could the next Pi be based to the BCM7445 SoC then? UltraHD resolution is not yet popular though, but the quad core ARMv7 Brahma 15 CPU would be nice to have. The SD could be replaced by 4G flash rom. Isn't it possible to run programs (like Linux kernel) straight from the flash (mapped to processors...
by mhelin
Wed Jan 22, 2014 4:13 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Reading 100k Potentiometer
Replies: 25
Views: 12593

Re: Reading 100k Potentiometer

Easy way to measure resistance of potentiometer is to use to GPIO pins, first outputs voltage (3v3) to pot and the pot sweeper connected via cap to ground charges and outputs a logical "1" to GPIO input pin. The faster it charges the more open the potentiometer is, so you just calculate the time bet...
by mhelin
Fri Jan 17, 2014 7:26 pm
Forum: Camera board
Topic: Any plans for a lensless version?
Replies: 8
Views: 1199

Re: Any plans for a lensless version?

gordon77 wrote:
Why ? I removed the lens so I could attach the camera to my telescope, works OK :D
So you have just some eyepiece and the bare sensor mounted on top of it?
by mhelin
Wed Jan 15, 2014 6:36 pm
Forum: Camera board
Topic: Camera module from ebay , are they genuine?
Replies: 19
Views: 5987

Re: Camera module from ebay , are they genuine?

Not all people undestand English. Anyway, cloning doesn't get support here either. Maybe Foundation should rename the official camera to something else, the name "Raspberry Pi Camera" (or was it Camera Board, or just camera?) is too general, and it's meaning is almost the same as "a compatible came...

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