83 lines
2.6 KiB
Markdown
83 lines
2.6 KiB
Markdown
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# Video Terminal Hardware
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Build instructions for the video-terminal-revival project.
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## Bill of Materials
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- ESP32 development board
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- USB cable (for development)
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- 5V power source (may be a 12V step down converter)
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- Display with composite input (TV, monitor)
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- RCA cable
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- RCA socket
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- resistors: 2x 1k ohm
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- LK201 keyboard
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- RJ-11 socket
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- MAX2323 TTL-RS232 conversion board
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- 12V power source + connector socket
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## Build
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### Display
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Connect the TV via the RCA cable to the RCA socket, then through a voltage divider into the ESP32:
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```
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ESP32 TV
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-------+
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GND |-+------------------ Composite (-)
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| | ____ 1k ohm
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| +-|____|-+ (RCA socket)
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| ____ |
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pin25 |---|____|-+--------- Composite (+)
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-------+ 1k ohm
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```
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### Keyboard
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Connect the keyboard into the RJ-11 socket, hook that into a 12V power source and the RS-232 converter, then to the ESP32's serial port:
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```
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[GND][12V]
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[1] | | [2]
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------------------- MAX2323 ESP32
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| " " " " | +-----------+ +--------
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| E G 1 L | [1]--| <- - |-----------| GND
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| S N 2 K | [2]--| -> + |--[5V] |
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| P D V -> | x-| + <- |-----------| pin17
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| -> E | [GND]--| - -> |-----------| pin16
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| L S | +-----------+ +--------
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| K P |
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-- --
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-- --
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-------
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Looking into the RJ-11 Socket
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on the ESP32-side (i.e. DEC)
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```
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Source: [LK201 Interface](http://www.netbsd.org/docs/Hardware/Machines/DEC/lk201.html)
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### TTY
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This part depends on what serial port you are connecting to. Most SBCs (e.g. Orange Pi) provide pins for TTL serial port, alternatively you can use a USB-Serial dongle. Either way you can connect the ESP32 directly to this:
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```
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ESP32 Serial port
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-------+ +---
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GND |--------------|GND
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pin18 |--------------|TX
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pin19 |--------------|RX
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-------+ +---
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```
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### CPU
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The ESP32 should now be connected to both the keyboard and the display, as well as the "mainframe" (serial port) it will be talking to.
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For development (or at least the first flashing), all that remains is to connect it over USB to a computer with the Arduino IDE.
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For production use, connect it to a 5V power source.
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### Finishing
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For bonus points, place everything on a PCB, solder it, put it into a cool enclosure and go impress your friends!
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