Monday, November 20, 2017

Some Dreamcatcher Single Board Computer hardware info

The docs are limited...some basic questions are assumed to be common knowledge, I post stuff as I figure it out...

I took a photo of the SBC and ID'd the important parts, and what they are for.

I will say this is a single core Arm7 (Raspberry Pi Zero...or early RPi2) and built in RTL-SDR with 1.5Ghz LNA and +5v bias tee controllable.

The Raspberry Pi3 is MUCH faster and more capable of a computer.   However the RTL-SDR on this board is very accurate and very compatible with all the software I have thrown at it.

It will run everything but SpyServer (Airspy, SDR# folks).  Because it is a slower processor, it doesn't run very hot.   In my opinion still a very useful board...I wonder what it would cost to remake it using the quadcore ARM7 that the RPi3 uses.

Anyway, here are the important connections...


I can't tell if the switch (SW_FACTORY) between the USB ports and the power switch is used for anything...or how it is addressed.

Just up from the power switch, just up from LED11/AGP3 is a solder point marked LIPO_BAT.

The DIP switches above that are labeled PD3 and AUTO_BOOT...mine are in the up position, and it always auto boots when power is applied.

Just behind SW_FACTORY are two pins labeled CHG-IN ...makes you think that goes with the LIPO_BAT connector...and next to that is a CHGLED led.

From the docs, apparently you can hook up a OTG USB cable to the board and plug it into your computer, the DC will boot, and you will have terminal access through a comm port.

There is an unpopulated USB1 at the top of the board.

The populated USB slots at the upper left, start with USB2/WIFI  So apparently the wifi dongle is meant to plug in there.  Next two are labeled USB3 and USB4

To the right, below the RF cans is SPI2 with 5 unpopulated pins labeled

Below that is IC2 interface  TWI2  unpopulated
   GND, 3V3, SCK, SDA

Then UART1   
   GND, RX, TX, 3V3

Just left of the LED9/PWR  is an unpopulated JTAG connector. 
       RESET_N, GND,TD0, TCK, TMS, TO1, 3V3

Finally at bottom right is SPI1 with
       MOSI, MISO, CS0, CLK, GND

Very bottom has GPIO connectors.

Obviously most of the parts are software controllable...if you can find some documentation for it.

Sunday, November 19, 2017

Dreamcatcher SBC inital setup...and image creation.

As I experiment with th RTL portion of this board, I find that some of the software is incompatible with others...

So I spend a lot of time setting up from clean...then I make an image of that basic setup so I don't have to start from scratch...or so I thought.

I found out that my 'basic' image was a later version with a radio app installed.

So I made another fresh one.

Here is my process to make MY basic setup...(I use Windows)


Download Dreamcatcher Armbian image (currently Jessie linux) and write to SD card.  This page has some instructions and documentation...and links to image downloads.

Write to SD card (I use Etcher for this)

Stick in DC (inboard card slot...not the one at the corner 'SD0_OS') and boot. If it doesn't power up when you plug in power, then press and hold the power button at corner.

You will need a USB to Ethernet adapter until your wifi is setup.

I have this one from Anker.

Figure out the IP address to the USB ethernet adapter, and use Putty to login.

At first boot, there are no accounts other than root.

Login is root  and password is 1234

It will welcome you to Outernet and direct you to change the password, then create a user and password (I didn't fill out any of the name etc stuff).

(At this point I recommend logging out, and logging back in with your newly created username for the rest of the install.   Most other install docs assume you are root, but some of the software needs to be installed by a non root my docs assume you are logged in as the non root user.)

First there is a note in the RadioNerds docs that later versions of Armbian can 'brick' the device (doing an update)...I haven't noticed that yet, but here is what they recommend.  (puts the Kernal version on hold)

sudo apt-mark hold linux-dtb-next-sunxi linux-headers-next-sunxi linux-image-next-sunxi linux-firmware-image-next-sunxi

Next I do the updates.

sudo apt-get update
sudo apt-get upgrade

Now I activate and setup the WiFi.

sudo nmtui

It is pretty straight forward, you probably have to run it a few times to get it set need to EDIT and ACTIVATE a connection.

At this point I reboot, with the USB to ethernet dongle disconnected, and make sure the WiFi setup is still there...sometimes it isn't...or maybe I am just impatient...

Now for me, I want a VNC and need a web browser installed (neither are on this barebones image).

For the Browser...(I used Konqueror because I couldn't get Chromium to install)

sudo apt-get install konqueror

For the VNC...

sudo apt-get install task-lxde-desktop
sudo apt-get install xfonts-base
sudo apt-get install tightvncserver

Now set up the VNC


It will tell you to set a password, and shouldn't have any errors.

Now I need the VNC to start every time it boots...this is where I got the info.

Create and edit this file...

sudo sudo /etc/init.d/tightvncserver

add the following to the file (cut and paste).  Note halfway down where you ID the VNCUSER  put in the username you made, or current username on the Dreamcatcher...I only have one user, so I put that one down.

# Provides: tightvncserver
# Required-Start: $syslog
# Required-Stop: $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: vnc server
# Description:
# /etc/init.d/tightvncserver
# Set the VNCUSER variable to the name of the user to start tightvncserver under
case "$1" in
#Change the display number below. The connection port will be 5900 + display #
su $VNCUSER -c '/usr/bin/tightvncserver :1'
echo "Starting TightVNC server for $VNCUSER"
pkill Xtightvnc
echo "Tightvncserver stopped"
echo "Usage: /etc/init.d/tightvncserver {start|stop}"
exit 1
exit 0

And to save out of Nano hold the CTRL key and press o .  To exit, CTRL-x

Now set some permissions...

sudo chmod 755 /etc/init.d/tightvncserver
sudo update-rc.d tightvncserver defaults

Now test that your editing works...of course if you are already running the VNC it will tell you that, but shouldn't have any errors.

sudo /etc/init.d/tightvncserver start

Of course at this point, you should reboot and make sure everything works.

If the VNC won't start...maybe you will see a reason here...(in my case I didn't change the VNCUSER in the file above)

nano /home/{your login}/.vnc/dreamcatcher:1.log

Now I shut down the Dreamcatcher pull the SD card out, and put it in your computer.

Make a copy of the image, I use Win32DiskImager.

If you only have one flash drive plugged in, it will automatically show at the 'Device'.

Click on the folder icon and select the directory and enter name to store the new image.

Once you do that, you will see the 'Read' button is it and in a few minutes you will have a new ready to run image.

Sunday, November 12, 2017

You can skip this, really...

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BTW, the Blogger filter strips all formatting and links from the comment, so that is why the strange characters I guess.

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