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#71
A20 / Re: LIME2 sun4i-codec not work...
Last post by LubOlimex - June 19, 2025, 11:20:10 AMOk here is some empirical info since I tested today with same board T2-OLinuXino-LIME2-IND and LIME2-SHIELD and some wav file. It played just fine (there was also sound on the headphones attached):
Didn't test before updating the image tho. I first ran apt update and apt upgrade to be sure I have the latest image, then rebooted. Didn't change anything in the overlays or settings.
You can find the wav file I used here:
https://ftp.olimex.com/TEMP/MP3test/file_example_WAV_5MG.wav
This means that audio is supported in the LIME2 images and config even tho it has no audio jacks by default. Here are few ideas to try:
1) Try re-writing a fresh image and running apt update and apt upgrade like me and test again. Maybe some configuration via olinuxino-overlay or other change caused the issue.
2) Maybe check if the board is properly recognized at start of boot, like this is what I got at boot:
"U-Boot 2021.04+olimex-1-20250305.102147 (Mar 05 2025 - 10:22:57 +0000) Allwinner Technology
CPU: Allwinner A20 (SUN7I)
ID: T2-OLinuXino-LIME2-IND Rev.N
SN: 00037DXX
MAC: 30:1F:9A:D1:XX:XX
I2C: ready
DRAM: 1 GiB
MMC: mmc@1c0f000: 0
"
You should get revision L, of course.
3) Since you are not using LIME2-SHIELD maybe also check the schematic of LIME2-SHIELD and compare with your hardware setup.
Code Select
root@a20-olinuxino:~# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: sun4icodec [sun4i-codec], device 0: CDC PCM Codec-0 [CDC PCM Codec-0]
Subdevices: 1/1
Subdevice #0: subdevice #0
root@a20-olinuxino:~# aplay file_example_WAV_5MG.wav
Playing WAVE 'file_example_WAV_5MG.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, StereoDidn't test before updating the image tho. I first ran apt update and apt upgrade to be sure I have the latest image, then rebooted. Didn't change anything in the overlays or settings.
You can find the wav file I used here:
https://ftp.olimex.com/TEMP/MP3test/file_example_WAV_5MG.wav
This means that audio is supported in the LIME2 images and config even tho it has no audio jacks by default. Here are few ideas to try:
1) Try re-writing a fresh image and running apt update and apt upgrade like me and test again. Maybe some configuration via olinuxino-overlay or other change caused the issue.
2) Maybe check if the board is properly recognized at start of boot, like this is what I got at boot:
"U-Boot 2021.04+olimex-1-20250305.102147 (Mar 05 2025 - 10:22:57 +0000) Allwinner Technology
CPU: Allwinner A20 (SUN7I)
ID: T2-OLinuXino-LIME2-IND Rev.N
SN: 00037DXX
MAC: 30:1F:9A:D1:XX:XX
I2C: ready
DRAM: 1 GiB
MMC: mmc@1c0f000: 0
"
You should get revision L, of course.
3) Since you are not using LIME2-SHIELD maybe also check the schematic of LIME2-SHIELD and compare with your hardware setup.
#72
A20 / Re: LIME2 sun4i-codec not work...
Last post by LubOlimex - June 19, 2025, 10:01:33 AMSo how is the audio output connected then? Do you have drawing or schematic? Is it similar to what we did in A20-OLinuXino-MICRO?
#73
A20 / Re: LIME2 sun4i-codec not work...
Last post by zeallin - June 19, 2025, 09:08:42 AMThank you very much my friend!
1. I am not using LIME2-SHIELD since we used GPIO-1 with our addon board
2. The overlay of LIME2-SHIELD seems not found in the olinuxino-overlay tool
3. It is the amazing T2-OLinuXino-LIME2-IND, version Rev.L
1. I am not using LIME2-SHIELD since we used GPIO-1 with our addon board
2. The overlay of LIME2-SHIELD seems not found in the olinuxino-overlay tool
3. It is the amazing T2-OLinuXino-LIME2-IND, version Rev.L
#74
JTAG / Re: ARM-USB-TINY-H working / A...
Last post by LubOlimex - June 19, 2025, 08:23:45 AMEven with cabling confirmed working it can be either a problem with this specific JTAG or wiring of this specific board or config for your custom board or OCD JTAG (or both).
My advice is to also test both JTAGs with some simpler and standard STM32 board (like some discovery board or similar) if you can borrow and then we can deduct if it is a problem with this specific JTAG or something related to the wiring or config of the target.
My advice is to also test both JTAGs with some simpler and standard STM32 board (like some discovery board or similar) if you can borrow and then we can deduct if it is a problem with this specific JTAG or something related to the wiring or config of the target.
#75
JTAG / Re: ARM-USB-TINY-H working / A...
Last post by jhersh - June 18, 2025, 05:32:50 PMThe board is self powered. As I mentioned, I used the identical short cable as I used on the TINY which works great. Yes, it is attached directly to the OCD, just like I did with the TINY. I haven't used the OCD device in years, so I'm not sure if it is working for other targets, but I would expect that whatever is going on would also be the same issue on another board.
#76
A20 / Re: LIME2 sun4i-codec not work...
Last post by LubOlimex - June 18, 2025, 02:38:38 PMI am not sure if audio is enabled for the LIME2 since the board has no audio jacks, I think it is not enabled on purpose to have more free GPIOs. Are you using LIME2-SHIELD? Try enabling the overlay for LIME2-SHIELD instead. It might be in olinuxino-overlay. Which variant of the LIME2 board? I will test too.
#77
A20 / Re: LIME2 sun4i-codec not work...
Last post by zeallin - June 18, 2025, 12:20:17 PMYeah I've tried following scenario (olinuxino-reset is executed):
1. run olinuxino-overlay to enable sun4icodec then reset (HDMI plugged) -> same aplay fail
2. based on step 1, use olinuxino-display switch to LCD 10' no TS (HDMI unplugged) -> same aplay fail
3. based on step 1, use olinuxino-display switch to DISABLE, (HDMI unplugged) -> same aplay fail
I found when I enabled the sun4icodec then the sun4ihdmi is gone. but when called olinuxino-reset the sun4ihdmi is backed is this expected?
1. run olinuxino-overlay to enable sun4icodec then reset (HDMI plugged) -> same aplay fail
2. based on step 1, use olinuxino-display switch to LCD 10' no TS (HDMI unplugged) -> same aplay fail
3. based on step 1, use olinuxino-display switch to DISABLE, (HDMI unplugged) -> same aplay fail
I found when I enabled the sun4icodec then the sun4ihdmi is gone. but when called olinuxino-reset the sun4ihdmi is backed is this expected?
#78
JTAG / Re: ARM-USB-TINY-H working / A...
Last post by LubOlimex - June 18, 2025, 09:29:22 AMThese errors usually indicate a problem between the ARM-USB-OCD-H and the target. Either wiring issue or powering issue.
Did you attach the 20-10 adapter directly to the ARM-USB-OCD-H? Keep the wires short else there might be timeouts.
Did you test the ARM-USB-OCD-H with a simple, proven to work board? Does it work well with other targets?
How do you power the target? Is it via the ARM-USB-OCD-H? Try powering from external source.
Did you attach the 20-10 adapter directly to the ARM-USB-OCD-H? Keep the wires short else there might be timeouts.
Did you test the ARM-USB-OCD-H with a simple, proven to work board? Does it work well with other targets?
How do you power the target? Is it via the ARM-USB-OCD-H? Try powering from external source.
#79
Biofeedback - EEG, ECG, EKG / Re: New Windows application fo...
Last post by michaloblastni - June 18, 2025, 08:09:20 AMFinally, I found how to attach the EEG-SMT electrodes: 
Simply buy a white elastic headband. Use a needle and thread to sew EEG-SMT electrodes to the headband from the inside. EEG-SMT electrodes have 4 small holes through which you can sew them. If you have a soldering iron and solder, solder gold-plated pins (or ordinary blunt pins) to the electrodes to make them conduct better.
I also found you can solder an ordinary wire to an EEG-SMT electrode and touch your head with the wire. It works the same. A wire is much smaller.
Simply buy a white elastic headband. Use a needle and thread to sew EEG-SMT electrodes to the headband from the inside. EEG-SMT electrodes have 4 small holes through which you can sew them. If you have a soldering iron and solder, solder gold-plated pins (or ordinary blunt pins) to the electrodes to make them conduct better.
I also found you can solder an ordinary wire to an EEG-SMT electrode and touch your head with the wire. It works the same. A wire is much smaller.
#80
A20 / Re: LIME2 sun4i-codec not work...
Last post by LubOlimex - June 18, 2025, 08:08:26 AMWhat happens if you try the different options in olinuxino-display? E.g. with HDMI output set, with automatic set, with something else selected? Maybe first run olinuxino-reset and reboot to revert any changes configuration you might have done and forgotten about.