For another project I'm working on, I made a super cheap and easy to build single chip VT100 terminal. You can find the github here:
https://github.com/profdc9/OneChipTerminal
It uses the Bluepill / STM32F103C8T6 processor which is easy to get from many sources.
A NTSC monitor, PS/2 keyboard, and a serial device are used with it.
This might be useful for those of you making do-it-yourself computers with serial terminal connections.
Dan
That's an interesting little project... I may have to make one of those... or 5...
It would probably also be possible to do something similar with the BPi M2 Zero, since it can do USB keyboard input and has a serial port and HDMI out. That makes it mostly just a software project because you would only need to hook up an RS-232 level converter/DB9 module to the TTL serial port. This might be kind of overkill for a lot of things since the BPi is essentially a complete Linux or Android computer...
I have a Pi Zero terminal for my RC2014; Serial in, HDMI out. USB keyboard support is there but meh. Definitely overkill hardware wise, but nice. Something like this could be much more sensible I would think.
So I ordered boards for this from JLCPCB... and I've got two boards mostly assembled... Waiting for the microcontroller modules... should be here on Monday or Tuesday.
But other than that, two questions related to resistors...
First... R7 is shown on the schematic as 240 Ohms... I don't have any of those and it doesn't seem like a common value... is 220 Ohm close enough or would 300 be better to use?
Second... R9 is shown as "NC" on the schematic... but the pic on the GitHub site shows a resistor there... is this resistor needed? If so, what value should it be? I guess I should look at the pic and decode the colored bands and see...
Anyway, just thought I'd ask about these questions before I solder in the resistors. Not that it would be the end of the world to remove them if I put the wrong thing in on a faulty guess, but better not to have to.
Oh... I always like to have a Bill of materials for a project so I made one for this...
I really hate the formatting on here sometimes... I can never figure out how to set the font to something fixed width and the preformatted tags never work for me.
And I can't seem to find the place on here anymore to attach a file.
Don't put a resistor at R9, it doesn't need it and it will only make it worse.
R7 as 220 ohms should work fine. Most NTSC inputs aren't very picky.
Dan
Thanks! That's what I was looking for!
I should be able to complete at least two on Monday or Tuesday when the microcontrollers and the RCA jacks come in.
I've got all 5 boards assembled... Just trying to program the STM boards... I installed the newest version of the Arduino IDE and the STM support... But when I try to Verify/Compile the code from GitHub I get:
/home/leeh/src/OneChipTerminal/OneChipTerminal/OneChipTerminal.ino:8:10: fatal error: libmaple/libmaple.h: No such file or directory 8 | #include <libmaple/libmaple.h> | ^~~~~~~~~~~~~~~~~~~~~compilation terminated.
exit status 1
Compilation error: libmaple/libmaple.h: No such file or directory
Any ideas? I've tried googling it but I'm not finding much on where to find this library.
did you try github.com/leaflabs/libmaple/ ?
No... for some reason that didn't come up when I searched... but thanks, I will take a look.
I was able to find the github project for libmaple, but I've not yet figured out how to get it imported into Arduino IDE and the project built. This whole thing seemns harder than it should be.
Just been thinking... The Murmulator which I've built a few of would be able to be used similarly to this with the right software, except that it doesn't have an RS-232 serial port. However it does have the advantage of either VGA or HDMI output for video... I'm thinking these two projects could be mashed together to make a one chip terminal with VGA or HDMI video out.
I need to revisit this project and see if I can get the software to build. If I remember right I built seeral of these boards and then got distracted before I got the software compiled and working.
Maybe if someone has it built they can attach it to this thread?