While I've found many projects for connecting the Sun serial based keyboards to a modern machine via USB, I've never found anything to connect a USB keyboard onto a classical Sun workstation.
This project allows you to connect a USB keyboard and mouse to a Sun workstation, using a Raspberry Pico as a bridge.
I've used two SN74LVC244AN as level shifters, one for 3.3V to 5V (from Pico to Sun), and one for 5V to 3.3V (from Sun to Pico). There are probably smaller shifters than the octal shifter I found, but I couldn't find any.
The Pico board is powered by the Sun workstation's 5V supply.
This project is currently targetting Pico SDK 1.5.1, and the corresponding TinyUSB version.
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Emulate the left keyboard function keys by entering LeftShift+LeftControl and the corresponding key
PC Function F1 Stop F2 Again 1 Props 2 Undo Q Front W Copy A Open S Paste Z Find X Cut Breaking into OpenFirmware would be LeftShift+LeftControl+F1+A
- Keyboard power on. Shorting minidin pin 7 to 5V rail powers on the system, however, the 5V rail is unpowered when the system is off - so the Pico is also unpowered in this state.
- LED indicators (num - caps and scroll lock).
- Switching layouts. PC or Unix layout and international layout (the emulated keyboard responds US for now).
Make sure the Pico SDK has been checked out, as detailed by the Pi foundation.
mkdir build && cd build
PICO_SDK_PATH=../../pico-sdk cmake ..
make
If your flashing with a Raspberry Pi, flash the firmware using
openocd -f interface/raspberrypi-swd.cfg -f target/rp2040.cfg -c "program usb2sun.elf verify reset exit"
Or copy usb2sun.uf2 onto the Pico when it's in flash mode.
Connect a USB mouse and keyboard using the OTG adapter. Wireless combo sets will work best, as they do not require a hub.
The project can be either plugged directly into the keyboard port on the workstation, or daisy-chained to a Sun keyboard. If daisy-chaining to the keyboard, do not connect the UART1 pins (6 and 7), only connect UART0 TX (1) to the Mouse TX pin on the minidin.
- Raspberry Pico
- 8 pin minidin male cable (I used https://no.rs-online.com/web/p/din-cable-assemblies/0463518)
- 2 SN74LVC244AN
- USB OTG adapter
Raspberry Pico
UART0 TX * Pin 1-----|USB|------Pin 40 * 5V
* Pin 2 `‾‾‾´ Pin 39 *
* Pin 3 Pin 38 * GND
* Pin 4 Pin 37 *
* Pin 5 Pin 36 * 3V3
UART1 TX * Pin 6 Pin 35 *
UART1 RX * Pin 7 Pin 34 *
* Pin 8 Pin 33 *
* Pin 9 .--------. Pin 32 *
* Pin 10 | | Pin 31 *
* Pin 11 | RP2040 | Pin 30 *
* Pin 12 `--------´ Pin 29 *
* Pin 13 Pin 28 *
* Pin 14 Pin 27 *
* Pin 15 Pin 26 *
* Pin 16 Pin 25 *
* Pin 17 π Pin 24 *
* Pin 18 Pin 23 *
* Pin 19 Pin 22 *
* Pin 20----------------Pin 21 *
5V to 3V3 level shifter
GND * Pin 1----------------Pin 20 * 3V3
KBD RX * Pin 2 Pin 19 *
* Pin 3 Pin 18 * UART1 RX
* Pin 4 Pin 17 *
* Pin 5 SN74LVC244AN Pin 16 *
* Pin 6 Pin 15 *
* Pin 7 Pin 14 *
* Pin 8 Pin 13 *
* Pin 9 Pin 12 *
GND * Pin 10----------------Pin 11 *
3V3 to 5V level shifter
GND * Pin 1----------------Pin 20 * 5V
UART1 TX * Pin 2 Pin 19 *
* Pin 3 Pin 18 * KBD TX
UART0 TX * Pin 4 Pin 17 *
* Pin 5 SN74LVC244AN Pin 16 * MOUSE TX
* Pin 6 Pin 15 *
* Pin 7 Pin 14 *
* Pin 8 Pin 13 *
* Pin 9 Pin 12 *
GND * Pin 10----------------Pin 11 *
MiniDin-8 plug
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| Pin | Function |
|---|---|
| 1 | GND |
| 2 | GND |
| 3 | 5V |
| 4 | MOUSE TX |
| 5 | KBD RX |
| 6 | KBD TX |
| 8 | 5V |