Posted inMod

Started Modifying DR-110

It's been a while since I stopped building things. But it's a new year, I'll try restarting it. For not making things for long, I cannot do anything aggressive yet. I would start with picking up an old DR-110 from my toy box to modify it. This device is half-dead. Upper half of the display is not functioning. Membrane switches are not working well, too. The case is nice looking, so it may be fun to keep it and make it work. But it's an old device and what can be done is pretty limited compared to contemporary feature rich devices. I would go simply with replacing the control by…
Posted inRaspberry Pi tech notes

Building DPDK on Raspberry Pi 3

I'm trying to build DPDK on Raspberry Pi 3 but couldn't do it on Raspbian since it's a 32-bit OS. DPDK uses several assembler instructions for ARM 8 that are only valid on 64-bit OS. So my effort starts with installing a 64-bit OS. I found SUSE has released 64-bit Linux for Raspberry Pi 3:https://en.opensuse.org/HCL:Raspberry_Pi3 I started with this OS image. Choosing the Image Three versions of distributions are avalable for Raspberry Pi 3: openSUSE Leap openSUSE Tumbleweed non-upstream openSUSE Tumbleweed I tried openSUSE Leap first, but could not zypper update. Then I tried openSUSE Tumbleweed. This worked fine. There are four variations of images: JeOS image (Just Enough OS)…
Posted inanalog2.0

Improvement of Analog2.0 LFO

The schematic above represents the latest Analog2.0 LFO circuit. This circuit has a long-existing problem. The oscillation affects the power supply and that causes instability in VCO pitch; You would hear the VCO pitch shifting along with the LFO’s oscillation. I’ve tried eliminating this problem.

Posted inanalog3 BeagleBone CAN

BeagleBone Green: Enable CAN on Startup

Three steps: Enable CAN overlay by configuring cape manager Configure network interface Install startup program 1. Enable CAN overlay Add following line in /etc/default/capemgr CAPE=BB-DCAN1 2. Configure network interface Add following lines in /etc/network/interfaces auto can0 iface can0 inet manual pre-up /sbin/ip link set $IFACE type can bitrate 1000000 listen-only off up /sbin/ifconfig $IFACE up down /sbin/ifconfig $IFACE down 3. Install startup program Setting the CAN interface to /etc/network/interface does not enable the CAN interface on startup for some reason. In order to workaround this problem, I installed a startup program as follows. Following link was helpful: Running a script on Beaglebone Black boot/ startup The startup script to run…
Posted inanalog3 BeagleBone

BeagleBoneGreen: Disabling Wi-Fi Power Management Permanently

The operating system is Debian. This is a dirty solution but it does work anyway. root@beaglebone:~# cat /etc/pm/power.d/wlan0_pm_off #!/bin/bash [ -x /sbin/iwconfig ] || exit 0 [ -n "`/sbin/iwconfig 2>/dev/null | grep wlan0`" ] || exit 0 /sbin/iwconfig wlan0 power off root@beaglebone:~# crontab -l | grep -v "^#" */1 * * * * /etc/pm/power.d/wlan0_pm_off root@beaglebone:~# iwconfig wlan0 wlan0 IEEE 802.11abgn ESSID:"*****" ... Power Management:off ...
Posted inanalog3 BeagleBone CAN

Test CAN connection between BeagleBone and MIDI/CAN converter

1. Enabled CAN at 1Mbps on BeagleBone: Following operations seem to be necessary every BeagleBone boot. TBD to setup auto configuration on startup. root@beaglebone:~# echo BB-DCAN1 > /sys/devices/platform/bone_capemgr/slots root@beaglebone:~# ip link set can0 up type can bitrate 500000 root@beaglebone:~# ip link set can0 up type can bitrate 1000000 root@beaglebone:~# ifconfig can0 can0      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00             UP RUNNING NOARP  MTU:16  Metric:1           RX packets:2 errors:0 dropped:2 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:10            RX bytes:16 (16.0 B)  TX bytes:0 (0.0…
Posted inanalog3 BeagleBone CAN

Enable CAN on the BeagleBone Green

I've tried to enable CAN on my BeagleBone Green board. I had to stop the work before verification, because my logic analyzer is unavailable now. I record what I did in this article to make things reproducible when the logic analyzer is back. There are several helpful links: http://www.embedded-things.com/bbb/enable-canbus-on-the-beaglebone-black/ http://electronics.stackexchange.com/questions/195416/beaglebone-black-can-bus-setup https://groups.google.com/forum/embed/?place=forum/beagleboard&showsearch=true&showpopout=true&showtabs=false&hideforumtitle=true&parenturl=http%3A%2F%2Fbeagleboard.org%2Fdiscuss%23bone_forum_embed#!category-topic/beagleboard/can/SjWwVngIPh8 Readings to understand device tree overlay: Device Tree for Dummies: http://events.linuxfoundation.jp/sites/events/files/slides/petazzoni-device-tree-dummies.pdf Device Tree Overlays (in adafruit) https://learn.adafruit.com/introduction-to-the-beaglebone-black-device-tree/device-tree-overlays Here are what I did: # make a workspace root@beaglebone:~# mkdir can root@beaglebone:~# cd can root@beaglebone:~/can# pwd /root/can # check if CAN is enabled ... no root@beaglebone:~/can# dmesg | grep can # take backup of the original device tree blob file for…
Posted inanalog3 BeagleBone CAN

BeagleBone notes

How to login from MacOS: Connect to the BeagleBone by a USB cable. MacOS restart is necessary for some reason. SSH to 192.168.7.2 WiFi setup: Use connmanctl as described in /etc/network/interfaces. root@beaglebone:~# connmanctl connmanctl> tether wifi disable Error disabling wifi tethering: Already disabled connmanctl> scan wifi Scan completed for wifi connmanctl> services Analog20 wifi_xxxxxxxxxxxxxxxxxxxxxxxxxxx_managed_psk connmanctl> agent on Agent registered connmanctl> connect wifi_xxxxxxxxxxxxxxxxxxxxxxxxxxx_managed_psk ... and so on Following links give useful information: http://xx-prime.hatenablog.com/entry/2016/08/13/012059 (in Japanese) https://www.mail-archive.com/beagleboard@googlegroups.com/msg40785.html The wlan0 device power management can be turned off by # iwconfig wlan0 power off TBD how to turn this off permanently. Take SD backup Insert the SD into the MacBook "diskutil list" to know…
Posted inanalog3 CAN tech notes

MCP2515 beyond 1MHz

For archival purpose: http://can-bus.996267.n3.nabble.com/Anybody-ever-run-an-MCP2515-at-greater-than-1Mbps-td1859.html you are certainly right about 1Mbps being the maximum speed of the official CAN spec. However, some of us like to break the rules :) I do :) I'm using CAN for a purpose different from controlling automobile so my breaking rule would not cause any death.