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by HiassofT
Wed Mar 20, 2019 10:58 am
Forum: Device Tree
Topic: Help needed with I2S device tree overlay
Replies: 3
Views: 76

Re: Help needed with I2S device tree overlay

The dual_soundcard overlay creates a card with two devices, playback on device 0 and record on device 1 card 1: Audio [Sierra Audio], device 1 : bcm2835-i2s-dir-hifi dir-hifi-1 [] So for recording you have to use arecord -D plughw:1 ,1 (or hw:1,1) to select the correct device. You probably also have...
by HiassofT
Fri Mar 15, 2019 7:39 pm
Forum: Troubleshooting
Topic: lirc on Raspberry Pi Zero W with gpio-ir
Replies: 2
Views: 139

Re: lirc on Raspberry Pi Zero W with gpio-ir

I'd recommend looking at the more modern tools, ir-ctl and ir-keytable - lircd and especially irrecord were always a bit troublesome to use. With ir-keytable you can see the decoded scancodes of various ir protocols and configure the in-kernel mapping from IR scancodes to Linux keycodes With ir-ctl ...
by HiassofT
Tue Mar 12, 2019 5:59 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2S Success (at last) !
Replies: 110
Views: 43865

Re: I2S Success (at last) !

I'm not exactly sure what you are trying to achieve, but if you just want some generic driver simply use

Code: Select all

dtoverlay=hifiberry-dac
The overlay / card driver doesn't require any specific hardware to be present.

so long,

Hias
by HiassofT
Tue Feb 26, 2019 7:20 pm
Forum: Raspbian
Topic: GPIO IR remote problem
Replies: 7
Views: 1049

Re: GPIO IR remote problem

You need to create 2 files. First one with your keymap which you store in /storage/.config/rc_keymaps - better don't name that file "rc_maps.cfg" like you are currently using but something like "my_remote". Then create a /storage/.config/rc_maps.cfg file with the mapping between driver, default keym...
by HiassofT
Thu Feb 21, 2019 7:14 pm
Forum: Media centres
Topic: [Guide][Testing] Kodi 18.0 Leia beta versions for Raspbian Stretch! [obsolete and locked]
Replies: 110
Views: 45532

Re: [Guide][Testing] Kodi 18.0 Leia beta versions for Raspbian Stretch!

One thing I noticed, it takes longer for return to video file selection after finishing any video I watched (20 to 40 seconds delay), unlike when it was still 17.6 (usually takes 10 secs or less). is this a known problem? any solution in the horizon? I didn't experience this issue myself yet but it...
by HiassofT
Sun Feb 10, 2019 10:13 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Incorrect bytes received through USB
Replies: 5
Views: 239

Re: Incorrect bytes received through USB

Keep in mind that read() and write() will transfer up to the number of bytes specified in the count argument - see "man 2 read" and "man 2 write" for details.

So always check the return value of these calls, especially in non-blocking mode as typically used with serial devices.

so long,

Hias
by HiassofT
Thu Jan 24, 2019 10:11 pm
Forum: Advanced users
Topic: Analogue audio redux
Replies: 73
Views: 19314

Re: Analogue audio redux

We've had a couple of reports in LibreELEC that playing live TV results in audio crackling when audio_pwm_mode=2. See eg here: https://www.raspberrypi.org/forums/viewtopic.php?f=35&t=231162&p=1415777#p1415724 I haven't checked that myself yet but I'm guessing deinterlacing, DRAM bandwitdh, GPU load ...
by HiassofT
Thu Jan 24, 2019 12:30 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 885
Views: 409708

Re: STICKY: The I2S sound thread.

Why is that left-justified mode more prone to errors than I2S? LRCLK phase problem maybe, PCM DAI cannot detect the first LRCLK edge? It's probably a limitation in the hardware implementation of the I2S block. My guess is the sync logic needs at least one clock cycle between the leading edge of LRC...
by HiassofT
Tue Jan 22, 2019 3:14 pm
Forum: General discussion
Topic: Features for future Pi, voltage/current reporting.
Replies: 49
Views: 1340

Re: Features for future Pi? (suggestion)

jamesh wrote:
Tue Jan 22, 2019 2:01 pm
Unfortunately the ADC's on the particular PMIC we use are non-functional. Apparently, having just spoken to someone who knows.
Ah, what a pity, would have been nice if that could have worked. But thanks a lot for checking into it!

so long,

Hias
by HiassofT
Tue Jan 22, 2019 1:32 pm
Forum: General discussion
Topic: Features for future Pi, voltage/current reporting.
Replies: 49
Views: 1340

Re: Features for future Pi? (suggestion)

The MxL7704 PMIC doesn't report its voltage input, but it does have two unused ADC inputs, one of which could perhaps be used to monitor the voltage input. That might be zero-cost except for the cost of tracking so maybe something to bear in mind for future generations of Pi if they use the same PM...
by HiassofT
Wed Jan 16, 2019 10:03 pm
Forum: Advanced users
Topic: Raspberry PI cold boot attack protected / Zero out RAM after boot?
Replies: 71
Views: 3142

Re: Raspberry PI cold boot attack protected / Zero out RAM after boot?

There are measures to remove the glue, so a second level of security is needed. If you can remove the glue and swap the SD card then doing it in bootcode.bin is too late. If you prevent people swapping the SD card or get access to the RPi itself then you can just clear RAM during the normal Linux b...
by HiassofT
Mon Jan 14, 2019 7:29 pm
Forum: Advanced users
Topic: Raspberry PI cold boot attack protected / Zero out RAM after boot?
Replies: 71
Views: 3142

Re: Raspberry PI cold boot attack protected / Zero out RAM after boot?

So effectively, we would need to update the hardcoded bootcode in the SOC to achieve this. (See 6by9's post above about secure boot as well) Which is not possible without very large sums of money expended. Basically yes, but it still is a very incomplete fix so IMO not worth the hassle. If one is c...
by HiassofT
Mon Jan 14, 2019 5:07 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 885
Views: 409708

Re: STICKY: The I2S sound thread.

The "DAI ... not registered - will retry" messages are harmless, they are caused by deferred probing. The important thing is that you get the "i2s mapping ok" message, this means the driver loaded successfully. I'm not familiar with that codec but I'd recommend checking the alsamixer settings - prob...
by HiassofT
Mon Jan 14, 2019 4:03 pm
Forum: Advanced users
Topic: Raspberry PI cold boot attack protected / Zero out RAM after boot?
Replies: 71
Views: 3142

Re: Raspberry PI cold boot attack protected / Zero out RAM after boot?

OTOH preserving RAM contents across reboots is very helpful when debugging things (eg using ramoops) as is JTAG because it means you can do post-mortem analysis when a system crashed. Yes, I certainly think ramoops is useful and should be enabled by default too. But that could work together fine wi...
by HiassofT
Mon Jan 14, 2019 2:04 pm
Forum: Advanced users
Topic: Raspberry PI cold boot attack protected / Zero out RAM after boot?
Replies: 71
Views: 3142

Re: Raspberry PI cold boot attack protected / Zero out RAM after boot?

Yes, wishlist material. Hmm, thinking about it, that may not work either. Given the fact that in the past when you switched RAM vendor you also released a new bootcode.bin, I am guessing RAM is enabled by that file on SD card, and access to it is still disabled when the on-chip bootrom is run. If y...
by HiassofT
Sun Jan 13, 2019 5:44 pm
Forum: Media centres
Topic: DVB TV HAT sound issues
Replies: 2
Views: 511

Re: DVB TV HAT sound issues

Add audio_pwm_mode=0 (you could also try with 1) to your config.txt.

There were several reports that the new, optimized analog audio code in the firmware causes issues with live TV (probably due to deinterlacing) and 1080p50/60 playback.

so long,

Hias
by HiassofT
Sun Jan 13, 2019 3:05 pm
Forum: Advanced users
Topic: Raspberry PI cold boot attack protected / Zero out RAM after boot?
Replies: 71
Views: 3142

Re: Raspberry PI cold boot attack protected / Zero out RAM after boot?

Has anyone ever tried reading ram after a cold boot or whatever, to see if there is anything in it? Not on the RPi or any semi-modern system / DRAM chip. But it's a very long known fact that DRAM can hold it's contents much longer than expected. The OS ROM of the Atari 8-bit XL/XE computers check f...
by HiassofT
Fri Jan 11, 2019 11:46 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: AtariSIO (Atari 8-bit peripheral emulator) with RPi support
Replies: 0
Views: 352

AtariSIO (Atari 8-bit peripheral emulator) with RPi support

After 3 months of testing and about 17 years after my initial release for x86 PCs I'm glad to announce that I just released the first version of AtariSIO that officially supports the Raspberry Pi: http://www.horus.com/~hias/atari/#atarisio atariserver, an Atari 8-bit peripheral emulator, now works b...
by HiassofT
Wed Jan 09, 2019 1:24 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO-IR with old IR-Receiver from Haupauge-PCI-Card
Replies: 1
Views: 373

Re: GPIO-IR with old IR-Receiver from Haupauge-PCI-Card

If you have a scope probe the signal pin. It should idle at VCC (3.3V) and go to low when an IR burst is received. With an RC6 (MCE) remote it looks like this: rc6.png Depending on the IR remote (protocol) the length of the bursts (low signal) and idle times (high signal) are multiples of roughly 50...
by HiassofT
Mon Dec 24, 2018 12:40 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 885
Views: 409708

Re: STICKY: The I2S sound thread.

How did you measure the frequencies? The 48kHz measurement shows a deviation of approx 40ppm which is about to be expected. A 3.072MHz bclk will be derived from the 500MHz PLL by using a fractional divider. Average frequency should be pretty spot on, but you may see a 2ns jitter when using a rather ...
by HiassofT
Wed Dec 19, 2018 12:52 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 885
Views: 409708

Re: STICKY: The I2S sound thread.

The bcm2835 driver seems to support SND_SOC_DAIFMT_CONT (which should also be controllable via the continuous-clock dai-link property, eg when using simple card) but I have never tested that. SND_SOC_DAIFMT_CONT will keep the clock running during pause, but when you close the audio device it'll be s...
by HiassofT
Mon Dec 10, 2018 9:05 pm
Forum: Advanced users
Topic: Volume Control data over SPI BUS
Replies: 3
Views: 167

Re: Volume Control data over SPI BUS

Look at the kernel docs in Documentation/sound, especially the soc folder. An check the existing drivers in sound/soc/codecs, there a re a lot of examples in there.

so long,

Hias
by HiassofT
Mon Dec 10, 2018 12:56 pm
Forum: Advanced users
Topic: Volume Control data over SPI BUS
Replies: 3
Views: 167

Re: Volume Control data over SPI BUS

If this is in addition to an (I2S) audio card then just create a codec driver that exposes a volume control mixer and add that as an auxiliary device in the card driver (aux_dev list in snd_soc_card or aux-devs DT property in the simple audio card driver). See for example the various amplifier drive...
by HiassofT
Fri Dec 07, 2018 8:55 pm
Forum: General discussion
Topic: Just about to buy Raspberry Pi for Media Centre and would appreciate help
Replies: 30
Views: 1211

Re: Just about to buy Raspberry Pi for Media Centre and would appreciate help

LibreELEC's tagline is "Just enough OS for Kodi". It's a minimal Linux OS with a few essential services and, of course Kodi. You can do most system configuration stuff (like enabling/disabling Samba, configuring network etc) from within Kodi and it's basically plug-and-play. The XBOX DVB-T dongle wo...
by HiassofT
Wed Dec 05, 2018 2:31 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 885
Views: 409708

Re: STICKY: The I2S sound thread.

Which kernel driver are you using? Codec drivers like spdif_rx support 16bit, 24bit (S24_LE) and 32bit (S32_LE, added to spdif-rx in kernel 4.16) and this is working fine - I've used 24bit recording with the Cirrus Logic audio card. Padding via bclk ratio / tdm slot with is a different thing. If you...

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