80 column VT100 terminal

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80 column VT100 terminal

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

 

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That's an interesting little

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...

 

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softwarejanitor wrote:That's
softwarejanitor wrote:

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 t

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. 

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So I ordered boards for this

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.

 

 

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Oh...  I always like to have

Oh...  I always like to have a Bill of materials for a project so I made one for this...

 

Bill of Materials

-----------------

 

Qty     Description             Location---     -----------             --------1       PCB1       MAX232                  U11       16 pin DIP socket       (U1)1       LM7805CT                U41       Mini DIN 6              P12       20 pin female header    (P1)1       Barrej Jack             J11       RCA Jack                J21       DE9 Male                J71       6 pin male header       J84       3 pin male header       JP1, JP2, JP3, JP42       2 pin male header       JP5, JP62       10uF capacitor          C1, C85       1uF Capacitor           C2, C3, C4, C5, C72       100nF capacitor         C6, C101       100uF caapacitor        C112       4.7K Ohm resistor       R1, R21       560 Ohm resistor        R61       240 Ohm resistor        R71       NC??? resistor          R9 

 

 

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I really hate the formatting

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.

 

 

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Don't put a resistor at R9,

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

 

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Thanks!  That's what I was

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.

 

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I've got all 5 boards

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.

 

 

 

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?

did you try github.com/leaflabs/libmaple/ ?

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robespierre wrote:did you try
robespierre wrote:

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.

 

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I was able to find the github

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.

 

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