https://github.com/bjoernQ/ps2keyboard-esp32c3

ESP32-C3 interfacing to a PS/2 Keyboard (bare-metal Rust)
https://github.com/bjoernQ/ps2keyboard-esp32c3

Last synced: about 1 month ago
JSON representation

ESP32-C3 interfacing to a PS/2 Keyboard (bare-metal Rust)

• Host: GitHub
• URL: https://github.com/bjoernQ/ps2keyboard-esp32c3
• Owner: bjoernQ
• License: apache-2.0
• Created: 2022-06-02T09:26:16.000Z (over 2 years ago)
• Default Branch: main
• Last Pushed: 2023-12-21T12:58:17.000Z (12 months ago)
• Last Synced: 2024-10-30T20:54:02.080Z (about 1 month ago)
• Language: Rust
• Size: 145 KB
• Stars: 9
• Watchers: 2
• Forks: 4
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE-APACHE

Awesome Lists containing this project

• awesome-esp-rust - ps2keyboard-esp32c3 - PS/2 keyboard implementation for ESP32-C3. (Projects / `no_std`)

README

        
# ESP32-C3 interfacing to a PS/2 Keyboard (bare-metal Rust)

The example of connecting a PS/2 keyboard and USB keyboard with PS/2 COMBO mode support to ESP32-C3.

You need to build it with the release profile (i.e. `cargo run --release`) since otherwise the interrupt latency is too slow.

![Screenshot](docs/screenshot.png "Screenshot")

## Circuit

- 2 x 2.2kΩ resitors

- 2 x 120Ω resitors

```

    Keyboard                                    ESP32-C3

    5V      ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━  5V

    GND     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━  GND

                                        ┏━━━━━┓

    DATA    ━━━━━━━━━━━━━━━━━━━━━┳━━━━━━┫ 120 ┣━━━  IO1

                                 ┃      ┗━━━━━┛

                                ┏┻┓

                                ┃2┃

                                ┃.┃

                                ┃2┃

                                ┃k┃

                                ┗┳┛

                                 ┃

                                 ┣━━━━━━━━━━━━━━━━  3V3

                                 ┃

                                ┏┻┓

                                ┃2┃

                                ┃.┃

                                ┃2┃

                                ┃k┃

                                ┗┳┛

                                 ┃      ┏━━━━━┓

    CLK     ━━━━━━━━━━━━━━━━━━━━━┻━━━━━━┫ 120 ┣━━━  IO2

                                        ┗━━━━━┛

```

### Wiring to PS/2 connector

The pinout of PS/2 connector is available at [Wikipedia](https://en.wikipedia.org/wiki/PS/2_port).

Hint 1: use [wire wrapping](https://youtu.be/L-463vchW0o?si=MtQrXpbTJznikXSJ) to connect wires to PS/2 connector

Hint 2: make sure to flip the [PS/2 pinout](https://en.wikipedia.org/wiki/PS/2_port#/media/File:PS-2_Y-cable_pinout_female.gif) if connecting to the male part the connector or to the back part of the connector.

### Wiring to USB connector

The same circuit works with USB keyboards with PS/2 COMBO mode support.

It's sufficient to replace PS/2 connector with USB connector according

the schematics [USB to PS2 schematics](https://www.instructables.com/USB-to-PS2-convertor/).

## Examples

### Keyboard to serial converter

The example converts keyboard to serial which can be then consumed by other board.

The receiver board can use [pc-keyboard crate](https://crates.io/crates/pc-keyboard) to decode signals. The following connection is used in [RustZX-ESP32](https://github.com/georgik/rustzx-esp32/tree/main/m5stack-cores3) project.

```

  ESP32-C3 Converter                         ESP32-S3 Receiver

     RX IO4 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ TX IO17

     TX IO5 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ RX IO18

     GND    ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ GND

```

Run: `cargo run --release --example keyboard_to_serial`

### Keyboard to serial converter - Embassy

Async implementation of the converter with Embassy.

Note: CPU must be clocked at 160MHz to decode values properly,

the frequency 80 MHz is not sufficient.

Run: `cargo run --release --example embassy_keyboard_to_serial --features embassy`