# interface1

A serial attached Arduino interface using the National Semiconductor DP8340 and DP8341.

## Schematic

![Schematic](hardware/schematic.svg)

## Materials

This interface requires an [Arduino Mega](https://store.arduino.cc/usa/mega-2560-r3).

 Item | Quantity | Description                   | Reference | Part Number                   | Source
:----:|---------:|-------------------------------|-----------|-------------------------------|----------------
1     | 1        | IBM 3270 Protocol Transmitter | U1        | National Semiconductor DP8340 | eBay - Obsolete
2     | 1        | IBM 3270 Protocol Receiver    | U2        | National Semiconductor DP8341 | eBay - Obsolete
3     | 1        | Quad RS-422 Line Driver       | U3        | Texas Instruments DS3487      | eBay - Obsolete
4     | 1        | Pulse Transformer - 1:1:1     | T1        | Pulse PE-5762                 | eBay - Obsolete
5     | 1        | Crystal - 18.867 MHz          | Y1        | IQD LFXTAL057125 *            | [Mouser](https://www.mouser.com/ProductDetail/IQD/LFXTAL057125Bulk?qs=%2Fha2pyFaduieSzBxw7UAJRZlCXjBZuIKPyofrMyYW7wVunrhuBMeiQd4MCF50LLz)
6     | 2        | Resistor - 33 ohm             | R2, R4    |                               | [Mouser](https://www.mouser.com/ProductDetail/Xicon/271-33-RC?qs=sGAEpiMZZMu61qfTUdNhGzoeXLT9qgk%252BV159XfY8c4Q%3D)
7     | 1        | Resistor - 120 ohm            | R6        |                               | [Mouser](https://www.mouser.com/ProductDetail/Xicon/271-120-RC?qs=sGAEpiMZZMu61qfTUdNhG7Of23Pr6gu8rRE5UXBJoDw%3D)
8     | 2        | Resistor - 150 ohm            | R1, R5    |                               | [Mouser](https://www.mouser.com/ProductDetail/Xicon/271-150-RC?qs=sGAEpiMZZMu61qfTUdNhG2ZzrN2CiS9nBcPQNrtAXYk%3D)
9     | 1        | Resistor - 500 ohm            | R7        |                               | [Mouser](https://www.mouser.com/ProductDetail/Xicon/271-499-RC?qs=sGAEpiMZZMu61qfTUdNhG6lpw21m8SOsvE2iEnaSg1s%3D)
10    | 1        | Resistor - 510 ohm            | R3        |                               | [Mouser](https://www.mouser.com/ProductDetail/Xicon/271-510-RC?qs=sGAEpiMZZMu61qfTUdNhG9RrhBeDi8B8FBVTnOgGHiw%3D)
11    | 1        | Capacitor - 30pF              | C1        |                               | [Mouser](https://www.mouser.com/ProductDetail/Vishay-Cera-Mite/561R10TCCQ30?qs=sGAEpiMZZMt1mVBmZSXTPNbSVgF1iSv4q4pBhPBLwuM%3D)
12    | 1        | Coax Connector                | J1        |                               |

\* - SMD

## Firmware

The firmware currently provides the ability to send commands and receive responses - it is designed to be used to implement a terminal controller, not to emulate a terminal.