Difference between revisions of "TinyPS2"

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[[File:TinyPS2_P899_cropped-720px.jpg]]
+
See [[TinyPS2 Revs 1-3]] for ATTiny85 based build
 +
 
 +
[[File: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.
 +
 
 +
[[file:Keyboard_PS2_MicrosoftNatural.jpg]]
  
 
== Features ==
 
== Features ==
  
−
* PS/2 keyboard or mouse to TTL Level Serial converter based on [https://www.smbaker.com/ps2-ttlserial-adapter-for-rc2014-and-midi Scott Baker BLOG]
+
* [[QT_Py_(RP2040_based)|QT Py (RP2040 based)]]
−
* [https://www.microchip.com/en-us/product/ATtiny85 ATTiny85 8-bit CPU]
+
** Run at 125 MHz
−
** Run at 8 MHz in this use-case
+
** 2MB of In System Programmable (ISP) flash
−
** 8 KB of In System Programmable (ISP) flash
+
** 264KB of SRAM
−
** 8-MHz internal RC oscillator that can be used as the default clock
+
* 115,200 baud serial
−
** 512 bytes of EEPROM
+
** 57,600-250,000 are build time options
−
** 512 bytes of SRAM
 
−
* 115,200 baud
 
 
* 49x49mm ODAS form factor
 
* 49x49mm ODAS form factor
−
* 4-40 mounting holes
+
* (4) 4-40 mounting holes
 
* 3.3V or 5V operation
 
* 3.3V or 5V operation
 
* Current measurement
 
* Current measurement
−
** 1 mA @ 5V (without keyboard)
+
** TBD @ 5V (without keyboard)
−
** 13 mA @ 5V (including keyboard)
+
** TBD @ 5V (including keyboard)
−
** 8mA @ 3.3V (including keyboard)
+
** TBD @ 3.3V (including keyboard)
−
*** Requires a keyboard that works at 3.3V
+
*** Does not require a keyboard that works at 3.3V
 +
 
 +
=== CPU Connections ===
  
−
=== TinyPS2 Connections ===
+
[[file:TinyPS2_CPU_Rev4_Conns.PNG]]
  
−
[[file:TinyPS2_CPU_Pins.PNG]]
+
<pre>
 +
#define DATAPIN 27
 +
#define IRQPIN  26
 +
</pre>
  
 
== Connectors ==
 
== Connectors ==
Line 28: Line 39:
 
=== J1 - TTL Serial Connector ===
 
=== J1 - TTL Serial Connector ===
  
−
[[file:TinyPS2_J1.PNG]]
+
[[file:TinyPS2_J1_Rev4_Conns.PNG]]
  
−
# VCC (nearest to J1 silkscreem)
+
# VCC (pin nearest to J1 silkscreem)
 
# SERTX
 
# SERTX
 
# N/C
 
# N/C
Line 39: Line 50:
 
* Standard PS/2 Mini-DIN-6 connector
 
* Standard PS/2 Mini-DIN-6 connector
  
−
[[file:TinyPS2_J2_kbd.PNG]]
+
[[file:TinyPS2_J2_Rev4_Conns.PNG]]
−
 
 
−
=== H2 - In-System Programming Header ===
 
−
 
 
−
[[file:ICSP.PNG]]
 
−
 
 
−
* SPI connector to download ATTiny85
 
−
* 2x3 header
 
−
* Program ATTiny85 without PS/2 keyboard attached
 
−
* Pinout
 
−
 
 
−
# KBCLK
 
−
# VCC
 
−
# SERTX
 
−
# KBDAT
 
−
# RST*
 
−
# GND
 
−
 
 
−
== Firmware ==
 
−
 
 
−
* [https://github.com/land-boards/lb-Arduino-Code/tree/master/LBCards/TinyPS2 GitHib Repo for TinyPS2 Firmware]
 
−
 
 
−
[[file:ATtiny45-85.png]]
 
−
 
 
−
=== Scott Baker's build ===
 
−
 
 
−
* [https://www.smbaker.com/ps2-ttlserial-adapter-for-rc2014-and-midi Scott Baker's Build BLOG page]
 
−
 
 
−
<video type="youtube">cSaBCtcUoq4</video>
 
−
 
 
−
* [https://github.com/sbelectronics/ps2-ttlserial Scott's GitHub page]
 
−
** Scott appears to have used [https://obdev.at/products/crosspack/index.html Crosspack] for AVR software development
 
−
* Scott uses two libraries from other projects
 
−
** [https://github.com/thegaragelab/tinytemplate ATTiny85 UART Library] - The Garage Lab
 
−
*** [https://github.com/thegaragelab/tinytemplate/blob/master/firmware/shared/uart_send.c uart_send.c]
 
−
** [http://www.nerdkits.com/videos/interrupts_and_ps2_keyboard/ Interrupts: Interfacing a Microcontroller with a PS/2 Keyboard] - PS/2 Keyboard Library
 
−
* Scott has hex file
 
−
** FUSES = -U lfuse:w:0x62:m -U hfuse:w:0xdf:m -U efuse:w:0xff:m
 
−
** Downloaded using [[TL866ii_Plus_Programmer|TL866i]]
 
−
** Used Fuse bits from  Programmer
 
−
*** Matched lfuse values already
 
  
−
==== Tested Scott's Build ====
+
== Firmware Build Card Rev 4 ==
  
−
* Works really well
+
[[file:asciifull.png]]
−
* 115,200 baud
 
−
* Works at 3.3V or 5V
 
−
** Drops out around 3.15V - may need BOD bit changed?
 
  
−
=== TinyPS2V01 (Arduino UNO) ===
+
=== Arduino ===
  
−
* Tried replacing Scott's code with "standard" Arduino code with a lot of issues
+
* Card rev 4 uses a QTPy or XAIO RP2040 CPU
−
* First cut used libraries
+
* Arduino Library
−
** [https://www.pjrc.com/teensy/td_libs_PS2Keyboard.html PJRC PS/2 library]
+
** [https://github.com/techpaul/PS2KeyAdvanced PS2KeyAdvanced]
−
** [https://github.com/land-boards/lb-Arduino-Code/tree/master/LBCards/TinyPS2/TinyPS2V01 Read PS/2 print to screen]
+
* [https://github.com/land-boards/lb-Arduino-Code/blob/master/LBCards/TinyPS2/TinyPS2_PCB_Rev4_AdvKbd/TinyPS2_PCB_Rev4_AdvKbd.ino TinyPS2_PCB_Rev4_AdvKbd] - code
−
* Resources (Arduino UNO)
 
 
<pre>
 
<pre>
−
Sketch uses 3334 bytes (10%) of program storage space. Maximum is 32256 bytes.
+
#define DATAPIN 27
−
Global variables use 377 bytes (18%) of dynamic memory, leaving 1671 bytes for local variables. Maximum is 2048 bytes.
+
#define IRQPIN  26
 
</pre>
 
</pre>
−
* Issues "likely" due to single interrupt in ATTiny85
 
−
** Can't use Arduino libraries without conflict
 
−
** Both [https://docs.arduino.cc/learn/built-in-libraries/software-serial Arduino SoftSerial] and [https://www.arduino.cc/reference/en/libraries/ps2keyboard/ PS/2 routines] use this same interrupt
 
−
 
−
=== TinyPS2V02 ===
 
−
 
−
* Read PS/2 keyboard, write Serial (9600 baud)
 
−
* [https://www.pjrc.com/teensy/td_libs_PS2Keyboard.html PJRC PS/2 library]
 
−
* [https://docs.arduino.cc/learn/built-in-libraries/software-serial Software Serial library]
 
−
* [https://github.com/land-boards/lb-Arduino-Code/tree/master/LBCards/TinyPS2/TinyPS2V02 Main sketch]
 
−
** Didn't run when first tried
 
−
** Maybe PS2Keyboard library does not work on ATTiny85?
 
−
*** Proper interrupt support for ATTiny85?
 
−
* [https://thewanderingengineer.com/2014/08/11/pin-change-interrupts-on-attiny85/ Pin Change Interrupts on ATtiny85]
 
−
* Verified KBD data, clocks are reaching ATTiny85
 
−
* Code
 
−
<pre>
 
−
#include <SoftwareSerial.h>
 
−
#include <PS2Keyboard.h>
 
−
 
−
const int DataPin = 0;
 
−
const int IRQpin =  1;
 
−
 
−
#define rxPin 3
 
−
#define txPin 2
 
−
 
−
// Set up SoftwareSerial and PS/2 objects
 
−
SoftwareSerial mySerial =  SoftwareSerial(rxPin, txPin);
 
−
PS2Keyboard keyboard;
 
  
−
void setup() {
+
* Example code produces warning
  
−
  pinMode(rxPin, INPUT);
 
−
  pinMode(txPin, OUTPUT);
 
−
  mySerial.begin(9600);
 
−
 
 
−
  keyboard.begin(DataPin, IRQpin);
 
−
}
 
−
 
−
void loop() {
 
−
  if (keyboard.available())
 
−
  {
 
−
   
 
−
    // read the next key
 
−
    char c = keyboard.read();
 
−
    mySerial.write(c);
 
−
  }
 
−
}
 
−
</pre>
 
−
* Resources (ATTiny85)
 
 
<pre>
 
<pre>
−
Sketch uses 3126 bytes (38%) of program storage space. Maximum is 8192 bytes.
+
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).
−
Global variables use 241 bytes (47%) of dynamic memory, leaving 271 bytes for local variables. Maximum is 512 bytes.
+
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.
 
</pre>
 
</pre>
  
−
=== TinyPS2V03 ===
+
* Code works well!
−
 
 
−
* Test routine
 
−
** Sends out A-Z in serial line at 9600 baud (~100uS bit time)
 
−
* [https://docs.arduino.cc/learn/built-in-libraries/software-serial Software Serial library]
 
−
** Verifies SoftwareSerial works
 
−
 
 
−
* Test with [https://github.com/land-boards/lb-Arduino-Code/tree/master/LBCards/TinyPS2/TinyPS2V04 TinyPS04 sketch]
 
−
** 2 mS off/on on serial output pin verifies delay(2)
 
−
*** Caught missing bootloader (sets speed fuses)
 
−
 
 
−
=== TinyPS04 ===
 
  
−
* Test with [https://github.com/land-boards/lb-Arduino-Code/blob/master/LBCards/TinyPS2/TinyPS2V03/TinyPS2V03.ino TinyPS04 sketch]
+
=== C++ ===
−
* Toggle serial output line every 2 mS
 
−
* Verifies delay(2)
 
  
−
=== TinyPS05 ===
+
* [https://github.com/tvlad1234/pico-ps2Driv pico-ps2Driv] - SDK C code
  
−
* Intent: Verify interrupt from keyboard does not conflict with Software Serial
+
=== CircuitPython ===
−
* Toggles serial out line if char comes in
 
−
* Never toggles
 
  
−
== Programming Card ==
+
* CircuitPython support issues
 +
** [https://docs.circuitpython.org/en/latest/shared-bindings/ps2io/index.html PS/2 Library] - Not in Pico core modules
  
−
* [http://highlowtech.org/?p=1695 Programming procedure is taken from here]
 
−
* Add ATTiny Board support to Preferences, Path:
 
 
<pre>
 
<pre>
−
https://raw.githubusercontent.com/damellis/attiny/ide-1.6.x-boards-manager/package_damellis_attiny_index.json
+
>>> import ps2io
−
 
+
Traceback (most recent call last):
 +
  File "<stdin>", line 1, in <module>
 +
ImportError: no module named 'ps2io'
 
</pre>
 
</pre>
−
* Select ATTiny85, 8 Mhz
 
−
* '''Burn bootloader''' - Otherwise clock is way off
 
−
 
−
[[File:Arduino_IDE_ATTiny85.png]]
 
−
 
−
* [[ATProgHead]]
 
−
** Running Arduino as ISP
 
−
 
−
== Other People's Videos ==
 
−
 
−
* [https://www.smbaker.com/ps2-ttlserial-adapter-for-rc2014-and-midi Scott Baker's Build]
 
−
 
−
<video type="youtube">cSaBCtcUoq4</video>
 
−
 
−
<video type="youtube">PmJlDlI-Pb4</video>
 
  
 
== Schematic ==
 
== Schematic ==
Line 207: Line 99:
 
== Issues ==
 
== Issues ==
  
−
* Missing pull-up resistors on PS/2
+
* [[TinyPS2_Revs_1-3|Revs 1-3 are documented here]]
−
** Rev 2 - add pull-up resistors
+
 
−
** (There's pullups in the part so this may not be needed)
+
=== Rev 4 ===
−
* Missing C3 cap in sequence
+
 
−
** Rev 2 - change C4 => C3
+
* 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
  
 
== Assembly Sheet ==
 
== Assembly Sheet ==
  
−
* [[TinyPS2 Assembly Sheet]]
+
* [[TinyPS2 Rev 4 Assembly Sheet]]

Latest revision as of 16:51, 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 

#define DATAPIN 27
#define IRQPIN  26

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

Asciifull.png

Arduino

#define DATAPIN 27
#define IRQPIN  26
  • Example code produces 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.
  • Code works well!

C++

CircuitPython

  • 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

Assembly Sheet

Retrieved from "http://land-boards.com/blwiki/index.php?title=TinyPS2&oldid=18806"