Beaglebone, Beagleboard Black, Green, and Friends

• boot MicroSD card: hold user button while applying power
  • will still boot from MicroSD with a reboot command
• expand MicroSD partition after burning 4GB partition: sudo /opt/scripts/tools/grow_partition.sh

• Throwing Bagels: “modern” implementation of LEDScape
• Geocene: LEDScape that successfully compiles on Linux Kernel 4.19 (Debian Buster? 10)
  • to run you must enable the UIO driver
• open pixel control format
• open pixel control:the real deal with simulator, examples, etc.
  • this code with examples shows how to format everything for LEDScape

• The bone is running a DHCP client so if you run a DHCP server it will get assigned an IP address
• username: `debian` pw: `temppwd`
• The onboard flash is 4GB which makes it too small to do any updates on current OS
• current OS: Linux beaglebone 4.9.78-ti-r94 #1 SMP PREEMPT Fri Jan 26 21:26:24 UTC 2018 armv7l GNU/Linux
• current OS on 32GB MicroSD: Linux beaglebone 4.19.94-ti-r42 #1buster SMP PREEMPT Tue Mar 31 19:38:29 UTC 2020 armv7l GNU/Linux

• video tutorial

1. get jack running and playing audio on both machines
2. receiver will have some command similar to zita-n2j 10.42.0.249 9999 --buff 50
   1. the --buff 50 seems to eliminate distortion which was coming and going. The default is 10
3. receiver:
   1. jack_connect zita-n2j:out_1 system:playback_1
   2. jack_connect zita-n2j:out_2 system:playback_2
4. sender:
   1. sudo jackd -d alsa
   2. sudo zita-j2n 10.42.0.249 9999 --16bit
      1. --16bit might not be necessary but seems prudent to keep network traffic down
   3. testing: sudo mpg123-jack -a zita-j2n:in_1,zita-j2n:in_2 /tmp/file_example_MP3_5MG.mp3
   4. fixme: we need to get rid of the sudos. This is just a test. Fixed my adding: usermod -a -G audio yourUserID as shown here
   5. fixme: distorting. Seems fixed with –buff 50?
   6. fixme: why transmit 2 channels when we only need 1?

using Griffin iMic

• starting: jackd -d alsa -d hw:1,0
• testing: mpg123-jack file_example_MP3_5MG.mp3
• change volume to 75%: amixer -c 1 -- sset PCM Playback 75%

using Amazon special

• amixer -c 1 -- sset Headphone Playback 100%

or

• amixer -c 1 -- sset Speaker 100% (for the one that has no cables)

• ubuntu with shared ethernet connection runs a dhcp server by default on 10.42.x.x and assigns the ethernet card 10.42.0.1.
• so the perhaps incorrect but easy way to get internet with static IP is on the beagle:
  • get name of connection: connmanctl services You'll get a response that will have something like: ethernet_6cecebabbc6a_cable
  • then assign your static IP. This will be a persistent setting. Example:

sudo connmanctl config ethernet_6cecebabbc6a_cable --ipv4 manual 10.42.0.2 255.255.255.0 10.42.0.1 --nameservers 8.8.8.8 1.1.1.1

for the morbidly curious you can find (and maybe edit?) the settings connman is reading/writing at /var/lib/connman

see Connmanctl Cheat Sheet for connecting Wi-Fi card

1. Manually boot from the MicroSD (hold down the user/boot button).
2. run sudo dd if=/dev/zero of=/dev/mmcblk1 bs=1M count=1 to write zeros over the first 1MB of the eMMC
3. run sync
4. run sudo shutdown now
5. disconnect and then reconnect power

source