The Blaustahl USB dongle provides long-term storage for about 8000 characters of text. Simply plug the device into your computer and open any serial communications program that supports VT100 emulation (PuTTY, Tera Term, Minicom, screen, etc.) in order to access the built-in text editor.
This repo contains schematics, firmware and a 3D-printable case.
Find usage instructions and more information on the Blaustahl product page.
The following sections will describe how to connect to Blaustahl on different operating systems. Once you're connected, press CTRL-G to view the on-device help screen.
- Install screen or minicom:
$ sudo apt install screen
$ sudo apt install minicom
- After plugging in Blaustahl, find the device:
$ dmesg | grep ACM
- Connect to the device (for example):
$ screen /dev/ttyACM0
$ minicom -D /dev/ttyACM0
-
Open the Terminal application.
-
After plugging in Blaustahl, find the device:
$ ls /dev/tty.usbmodem*
- Connect to the device (for example):
$ screen /dev/tty.usbmodem1234561
Note: The default firmware isn't currently recognized by Windows, please update your firmware to blaustahl_cdconly.uf2 in order to access Blaustahl from Windows.
After the latest cdconly firmware is installed:
-
Download and install PuTTY.
-
After plugging in Blaustahl, find the device by opening Device Manager and looking under "Ports (COM & LPT)" for "USB Serial Device (COMx)".
-
Open PuTTY and set connection type to Serial. Enter COMx (e.g. COM4) in the serial line box and press the Open button.
Blaustahl includes a built-in text editor with four 80x24 pages of text. The cursor can be moved with the arrow keys. When you'd like to enter or delete text, press CTRL-W to toggle the write mode.
| Keypress | Action |
|---|---|
| CTRL-G | Help |
| CTRL-L | Refresh screen |
| CTRL-W | Toggle write mode |
| CTRL-S | Toggle status bar |
| CTRL-Y | Enter firmware update mode |
| PGUP/DN | Navigate between pages |
| $ | Move to end of line |
| ^ | Move to beginning of line |
The 'bs' utility program can be used to read and write the FRAM data. Note that it's not possible to use this utility with the cdconly firmware.
Build and install:
$ sudo apt install libusb-1.0-0-dev
$ cd sw
$ make
$ sudo make install
$ sudo bs -r my-backup.bin
The firmware can be updated over USB by pressing CTRL-Y in the text editor to enter the UF2 bootloader mode. You can also enter the bootloader by holding the button while plugging in the device.
Once in bootloader mode, you can update the firmware by dragging and dropping a new UF2 file to the device.
There are two firmware images available:
- blaustahl.uf2: USB composite device with USB-CDC and vendor interface
- blaustahl_cdconly.uf2: USB-CDC simple device
The vendor interface allows you to access the 'bs' utility and to develop custom software that interfaces with Blaustahl.
You can build the firmware from source, if you have pico-sdk installed:
$ cd firmware/blaustahl
$ mkdir build
$ cd build
$ cmake ..
$ make
In the event that the USB interface were to become obsolete or the RP2040 were to become non-functional, it should still be possible to recover the FRAM data using a SOP-8 test clip. The FRAM IC is marked "RS64".
One way to achieve this today is to load the Blaustahl firmware onto a Raspberry Pi Pico using the same SPI GPIOs as shown in the schematics, then hold the Blaustahl boot button while attaching a test clip to the FRAM IC. The text editor or 'bs' utility can then be used to recover the FRAM data.
The contents of this repo are released under the Lone Dynamics Open License.