Difference between revisions of "TinyPS2"

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ImportError: no module named 'ps2io'
 
ImportError: no module named 'ps2io'
 
</pre>
 
</pre>
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== Firmware Builds Card Revs 1-3 (ATTiny85) ==
 
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Two software builds:
 
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* Scott Baker's build
 
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* Arduino IDE port
 
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=== Scott Baker's Software Build ===
 
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* [https://www.smbaker.com/ps2-ttlserial-adapter-for-rc2014-and-midi Scott Baker's Build BLOG page]
 
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* Scott's demo video
 
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<video type="youtube">cSaBCtcUoq4</video>
 
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* [https://github.com/sbelectronics/ps2-ttlserial Scott's GitHub page]
 
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** Scott appears to have used [https://obdev.at/products/crosspack/index.html Crosspack] for AVR software development
 
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* Scott uses two libraries from other projects
 
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** [https://github.com/thegaragelab/tinytemplate ATTiny85 UART Library] - The Garage Lab
 
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*** [https://github.com/thegaragelab/tinytemplate/blob/master/firmware/shared/uart_send.c uart_send.c]
 
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** [http://www.nerdkits.com/videos/interrupts_and_ps2_keyboard/ Interrupts: Interfacing a Microcontroller with a PS/2 Keyboard] - PS/2 Keyboard Library
 
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==== Programming Scott's Build ====
 
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* Used [[TL866ii Plus Programmer]]
 
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* Scott has [https://github.com/land-boards/lb-Arduino-Code/blob/master/LBCards/TinyPS2/ScottBakerCode/serkey.hex serkey.hex file]
 
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** FUSES = -U lfuse:w:0x62:m -U hfuse:w:0xdf:m -U efuse:w:0xff:m
 
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** Used Fuse bits from  Programmer
 
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*** Matched lfuse values already
 
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==== Tested Scott's Build ====
 
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* Works really well
 
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* 115,200 baud
 
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* Works at 3.3V or 5V
 
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** Drops out around 3.15V - may need BOD bit changed?
 
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=== TinyPS2 Software Build Using Arduino IDE ===
 
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* Converted Scott Baker's build to the Arduino IDE
 
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** Move main init code to setup()
 
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** Move main inner loop to loop()
 
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* Compiled fairly easily
 
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* [https://github.com/land-boards/lb-Arduino-Code/tree/master/LBCards/TinyPS2/TinyPS2 GitHub Software Repo]
 
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* Resources (Arduino UNO)
 
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<pre>
 
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Sketch uses 850 bytes (10%) of program storage space. Maximum is 8192 bytes.
 
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Global variables use 15 bytes (2%) of dynamic memory, leaving 497 bytes for local variables. Maximum is 512 bytes.
 
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</pre>
 
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==== Setting Baud Rate ====
 
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* The implementation is optimized for higher baud rates - please don't use anything below 57600 on an 8MHz clock
 
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* It does work at up to 250000 baud but you may experience a small amount of dropped packets at that speed.
 
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* Set in TinyPS2.ino file
 
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<pre>
 
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#define BAUD_RATE 115200
 
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</pre>
 
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==== Arduino IDE Setup for ATTiny85 ====
 
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* [http://highlowtech.org/?p=1695 Programming procedure is taken from here]
 
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* Add ATTiny Board support to Preferences, Path:
 
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<pre>
 
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https://raw.githubusercontent.com/damellis/attiny/ide-1.6.x-boards-manager/package_damellis_attiny_index.json
 
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</pre>
 
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==== Programming Card (Arduino IDE) ====
 
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* Select ATTiny85, 8 Mhz
 
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* '''Burn bootloader''' - Otherwise clock is way off
 
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[[File:Arduino_IDE_ATTiny85.png]]
 
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* [[ATProgHead]]
 
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** Running Arduino as ISP
 
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* Can program from an Arduino UNO like this:
 
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[[file:ProgramFromArduinoUNO.jpg]]
 
  
 
== Schematic ==
 
== Schematic ==

Revision as of 09:31, 15 August 2022

See TinyPS2 Revs 1-3 for ATTiny85 based build

TinyPS2 Front Rev4 3D.png

Introduction

It is getting difficult to find ASCII serial keyboards for use in Retro-Computer projects. This card fills that need. The card is a PS/2 keyboard to TTL Level Serial adapter. PS/2 keyboards are still widely available.

Keyboard PS2 MicrosoftNatural.jpg

Features

  • QT Py (RP2040 based)
    • Run at 125 MHz
    • 2MB of In System Programmable (ISP) flash
    • 264KB of SRAM
  • 115,200 baud serial
    • 57,600-250,000 are build time options
  • 49x49mm ODAS form factor
  • (4) 4-40 mounting holes
  • 3.3V or 5V operation
  • Current measurement
    • TBD @ 5V (without keyboard)
    • TBD @ 5V (including keyboard)
    • TBD @ 3.3V (including keyboard)
      • Does not require a keyboard that works at 3.3V

CPU Connections

TinyPS2 CPU Rev4 Conns.PNG

Connectors

J1 - TTL Serial Connector

TinyPS2 J1 Rev4 Conns.PNG

  1. VCC (pin nearest to J1 silkscreem)
  2. SERTX
  3. N/C
  4. GND

J2 - PS/2

  • Standard PS/2 Mini-DIN-6 connector

TinyPS2 J2 Rev4 Conns.PNG

Firmware Build Card Rev 4

  • Card rev 4 uses a QTPy or XAIO RP2040 CPU
  • Arduino Library
  • Example code built with warning
WARNING: library PS2KeyAdvanced claims to run on avr, sam, samd1, stm32, esp32 architecture(s) and may be incompatible with your current board which runs on rp2040 architecture(s).
Sketch uses 82336 bytes (0%) of program storage space. Maximum is 16777216 bytes.
Global variables use 43096 bytes (15%) of dynamic memory, leaving 227240 bytes for local variables. Maximum is 270336 bytes.
  • CircuitPython support issues 
>>> import ps2io
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: no module named 'ps2io'

Schematic

Issues

Rev 4

  • Changed CPU
    • Was 8 MHz ATTiny85
    • Changed to QT PY or XAIO
  • Changed pin usage
  • Uses Hardware Transmitter in CPU
  • Keyboard runs at 5V
  • CPU runs at 3.3VV
  • 3.3V to 5V level shifter

Rev 3

  • Added D3 to J1 connector
  • Change from SMT parts to through hole parts
  • Silkscreen cleanups
    • Added ISP VCC/GND to silkscreen
    • Added silkscreen to J1 pins

TinyPS2 Rev3 3D.png

Rev 2

  • Fixed issues below

Rev 1

  • Missing pull-up resistors on PS/2
    • Rev 2 - add pull-up resistors
    • (There's pullups in the part so this may not be needed)
  • Missing C3 cap in sequence
    • Rev 2 - change C4 => C3

Assembly Sheet

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