TinyPS2

Features

• PS/2 keyboard or mouse to TTL Level Serial converter
• ATTiny85
  • 8 KB of flash
  • 8-MHz internal RC oscillator that can be used as the default clock
  • 512 bytes of EEPROM
  • 512 bytes of SRAM
• 115,200 baud
• 49x49mm ODAS form factor
• 4-40 mounting holes

Connectors

J1 - TTL Serial Connector

1. 5V
2. SERTX
3. N/C
4. GND

J2 - PS/2

• Standard PS/2 Mini-DIN-6 connector

H2 - In-System Programming Header

• SPI connector to download ATTiny85
• 2x3 header
• Program ATTiny85 without PS/2 keyboard attached
• Pinout

1. KBCLK
2. GND
3. SERTX
4. KBDAT
5. RST*
6. GND

Firmware

• GitHib Repo for TinyPS2 Firmware
• ( Add to Prefernces

https://raw.githubusercontent.com/damellis/attiny/ide-1.6.x-boards-manager/package_damellis_attiny_index.json

TinyPS2V01

• PJRC PS/2 library
• Read PS/2 print to screen
• Resources

Sketch uses 3334 bytes (10%) of program storage space. Maximum is 32256 bytes.
Global variables use 377 bytes (18%) of dynamic memory, leaving 1671 bytes for local variables. Maximum is 2048 bytes.

TinyPS2V02

• PJRC PS/2 library
• Software Serial library
• Resources

Sketch uses 3490 bytes (10%) of program storage space. Maximum is 32256 bytes.
Global variables use 241 bytes (11%) of dynamic memory, leaving 1807 bytes for local variables. Maximum is 2048 bytes.

Schematic

• Schematic

Issues

• Missing pull-up resistors on PS/2
  • Rev 2 - add pull-up resistors
• Missing C3 cap in sequence
  • Rev 2 - change C4 => C3

Assembly Sheet

• TinyPS2 Assembly Sheet