Title: A Modern Terminal Date: 20190812 Tags: hardware retrocomputers ======================================== Well, ratfactor beat me to it[0], but this is a little different. For retrocomputing, a couple of my systems only have serial terminal access. No problem using my laptop with a USB to serial adapter with, in some cases, a serial to TTL adapter. I use cu and xterm to complete the serial terminal emulator setup. The good points of this modern set up are that I can have a window with cu connected to the remote system and have other windows with code, documentation, or references and I can copy and paste and send files with XMODEM, etc. However, it leaves a couple of things to be desired. It's a bit wasteful to use the horsepower and energy of my full laptop just to act as a screen and keyboard for a simple 8-bit machine. I can't use my laptop for something else visual at the same time. It's also not quite as authentic as I'd like. I like to have my laptop on my lap. I haven't sat at a desk at home and my daily drivers have been laptops for some time. So going with a real CRT terminal from the 70's or 80's would be awesome, but not practical to my computing comfort. Small laptops came well after serial terminals were a thing so laptop form-factor terminals didn't come to be. But that's exactly what I want to have. My first thought was to buy a rack mount KVM monitor and keyboard as used in datacenters. Apparently datacenters print money because these units are over $1,000 new. That's laptop computer prices without any of the computer part. Used units that I found were around $600. Next plan. Since this is going to be for text only systems, I don't need a big high resolution display. So I found a nice 10 inch LCD monitor[1] on Amazon that had HDMI, VGA, composite, and USB input. The USB port is of particular importance later. I also bought a cheap mini chiclet keyboard hoping it would be similar to my laptop keyboard. I got one with a USB hub in case I wanted to hang any other USB stuff off of it for something. The hub turned out to be a mistake and I couldn't use the keyboard. But no loss, the keyboard felt awful to type on. So I found a fully mechanical mini keyboard[2] which is a bit wider but worth it. A nice authentic clickity-clack. The last piece of the puzzle was terminal emulation. I was looking at Geoff's ASCII Video Terminal[3] as an option (and may go to it later), but I'd have to source the parts myself and that felt a bit daunting for this project right now. One of my systems I will be using this with is an RC2014[4] which has an add-on card that uses a Raspberry Pi Zero and PiGFX[5] to provide PS/2 keyboard input and composite video out. I decided to go down that road DIY as PiGFX also supports USB keyboards and HDMI output. What it didn't provide, was USB hub support. So my cheap chiclet keyboard wasn't detected. Plan B's Apple keyboard also wasn't detected. So I had to find a keyboard with no USB hub built in. The Pi Zero can run off the USB port on the monitor so there is only one power source needed. Between the keyboard, monitor, and a little bit of circuitry currently on a breadboard (the Pi Zero is 3.3V and RC2014 is 5V so I have to split the voltage), I have a functional prototype serial terminal. I need to make a cable that incorporates the voltage divider and mount everything to a board for lap use. Bonus: The monitor is 12V, for automotive use, so I picked up a 12V battery[6] that includes a 5V USB port on it. So now I can power the terminal from battery AND even power the RC2014 all as one unit. Suddenly this became a Z80 "portable" computer. I might just replace the RC2014 with a smaller single board Z80 based computer and have exactly that. CP/M on the go. [0] gopher://sdf.org:70/0/users/ratfactor/phlog/2019-08-11-portable-computer [1] https://www.amazon.com/gp/product/B073ZBNBWK [2] https://www.amazon.com/gp/product/B01LXD7TP9 [3] http://geoffg.net/terminal.html [4] https://rc2014.co.uk/ [5] https://github.com/fbergama/pigfx [6] https://www.amazon.com/gp/product/B00ME3ZH7C