lostcarpark
Member
I know there's a Teensy PS/2 library. However, I think it's only suitable for connecting PS/2 devices to the Teensy.
How feasible is it to use a Teensy board to connect to retro computer with a PS/2 port but no USB port?
From my understanding of the PS/2 protocol, I would just need to connect the clock and data pins to Teensy pins, and pull low to output keyboard data. The obvious issue is that the PS/2 keyboard runs at 5V rather than 3.3V, so I'd really appreciate some advice before I start.
Some questions:
If the answer to Q1 is yes, then I can probably find out the others experimentally, of course.
If anyone knows of a similar project I can take ideas from, that would be very helpful.
Project background:
I'm working on an interface to convert a keyboard from a 1980s computer to one that will be able to work with more modern computers. The particular computer is a Sinclair QL, but it should be easy to adapt to any keyboard with a matrix pattern.
My original plan was to use it to control a Raspberry Pi running an emulator. However, I would now like to use with a FPGA board. Unfortunately, this only has a PS/2 keyboard connector.
More details of the project on GitHub: https://github.com/lostcarpark/ql_keyboard
How feasible is it to use a Teensy board to connect to retro computer with a PS/2 port but no USB port?
From my understanding of the PS/2 protocol, I would just need to connect the clock and data pins to Teensy pins, and pull low to output keyboard data. The obvious issue is that the PS/2 keyboard runs at 5V rather than 3.3V, so I'd really appreciate some advice before I start.
Some questions:
- Is it safe to connect Teensy pins to a PS/2 at all? I know some models don't have overvolt protection. I'm using the Teensy 4.0, which as far as I understand does.
- Both clock and data pins are normally high when not transmitting. Does the high level come from the computer end or the keyboard end?
- If from the device end, will the Teensy's 3.3V output be sufficient for the computer to recognise, or do I need to step the voltage up to 5V?
- If from the computer end, will the Tensy be able to pull the signal low?
If the answer to Q1 is yes, then I can probably find out the others experimentally, of course.
If anyone knows of a similar project I can take ideas from, that would be very helpful.
Project background:
I'm working on an interface to convert a keyboard from a 1980s computer to one that will be able to work with more modern computers. The particular computer is a Sinclair QL, but it should be easy to adapt to any keyboard with a matrix pattern.
My original plan was to use it to control a Raspberry Pi running an emulator. However, I would now like to use with a FPGA board. Unfortunately, this only has a PS/2 keyboard connector.
More details of the project on GitHub: https://github.com/lostcarpark/ql_keyboard