Hardware build instructions

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Dejvino 2021-03-14 12:54:25 +01:00
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Hardware.md Normal file
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# Video Terminal Hardware
Build instructions for the video-terminal-revival project.
## Bill of Materials
- ESP32 development board
- USB cable (for development)
- 5V power source (may be a 12V step down converter)
- Display with composite input (TV, monitor)
- RCA cable
- RCA socket
- resistors: 2x 1k ohm
- LK201 keyboard
- RJ-11 socket
- MAX2323 TTL-RS232 conversion board
- 12V power source + connector socket
## Build
### Display
Connect the TV via the RCA cable to the RCA socket, then through a voltage divider into the ESP32:
```
ESP32 TV
-------+
GND |-+------------------ Composite (-)
| | ____ 1k ohm
| +-|____|-+ (RCA socket)
| ____ |
pin25 |---|____|-+--------- Composite (+)
-------+ 1k ohm
```
### Keyboard
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:
```
[GND][12V]
[1] | | [2]
| | | |
------------------- MAX2323 ESP32
| " " " " | +-----------+ +--------
| E G 1 L | [1]--| <- - |-----------| GND
| S N 2 K | [2]--| -> + |--[5V] |
| P D V -> | x-| + <- |-----------| pin17
| -> E | [GND]--| - -> |-----------| pin16
| L S | +-----------+ +--------
| K P |
-- --
| |
-- --
| |
-------
Looking into the RJ-11 Socket
on the ESP32-side (i.e. DEC)
```
![LK201 connection](http://www.netbsd.org/docs/Hardware/Machines/DEC/LK201_connector.jpg)
Source: [LK201 Interface](http://www.netbsd.org/docs/Hardware/Machines/DEC/lk201.html)
### TTY
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:
```
ESP32 Serial port
-------+ +---
GND |--------------|GND
pin18 |--------------|TX
pin19 |--------------|RX
-------+ +---
```
### CPU
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.
For development (or at least the first flashing), all that remains is to connect it over USB to a computer with the Arduino IDE.
For production use, connect it to a 5V power source.
### Finishing
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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- [ESP32Lib](https://github.com/bitluni/ESP32Lib/tree/development) for composite video output
## Building
1. Connect up the hardware (TODO).
1. Connect up the hardware. See [Hardware.md](Hardware.md)
2. Get the Arduino IDE, Install ESP32 board package, Install ESP32Lib library.
3. Compile and upload the sketch in `video-terminal/video-terminal.ino`

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Custom ladders can be used by tweaking colorMinValue and colorMaxValue
*/
#define COMPOSITE_VIDEO_PIN 25 // hardcoded, this pin has a HW DAC
#include <ESP32Lib.h>
#include <Ressources/Font6x8.h>
#include <Ressources/CodePage437_8x8.h>
@ -43,7 +45,7 @@
#define FONT CodePage437_8x8
//pin configuration for DAC
const int outputPin = 25;
const int outputPin = COMPOSITE_VIDEO_PIN;
// A) B)
CompositeGrayDAC videodisplay;
// C) D)

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* and modified by Peter Scargill.
*/
#define SERIAL_KBD_BAUDRATE 4800 // hardcoded LK201 baud rate
#define SERIAL_KBD_RX_PIN 16 // hardcoded in Serial2
#define SERIAL_KBD_TX_PIN 17 // hardcoded in Serial2
#define SERIAL_TTY_BAUDRATE 9600 // configurable, depends on the TTY
#define SERIAL_TTY_CONFIG SERIAL_8N1 // configurable, depends on the TTY
#define SERIAL_TTY_RX_PIN 18 // configurable
#define SERIAL_TTY_TX_PIN 19 // configurable
#include <SPI.h>
#include <Adafruit_GFX.h>
@ -110,14 +119,12 @@ void setup() {
Serial.println("Running!");
// TTY host
SerialTty.begin(9600, SERIAL_8N1, 18, 19, false, 100);
SerialTty.begin(SERIAL_TTY_BAUDRATE, SERIAL_TTY_CONFIG, SERIAL_TTY_RX_PIN, SERIAL_TTY_TX_PIN, false, 100);
// LK201 keyboard connected to pins 16 and 17
SerialKbd.begin(4800);
SerialKbd.begin(SERIAL_KBD_BAUDRATE);
display.setup();
//uint16_t tftID = tft.readID();
//tft.begin(tftID);
input_init();