PDDuino

A Tandy Portable Disk Drive emultaor implemented on Arduino, using a micro-sd card for storage.

PDDuino is based on SD2TPDD by Jimmy Petit.

This fork adds:

• TPDD2-style bootstrapper (A way to install a TPDD Client onto the computer)
  
• Power saving sleep mode
  
• Current working directory displayed in TS-DOS
  
• Disk-activity led
  
• Support for Teensy 3.5 and 3.6 SDIO sd-card reader hardware
  
• Support for Adafruit Feather 32u4 Adalogger
  
• Support for Adafruit Feather M0 Adalogger (20200916 broken)
  

Requirements / Setup

Software

See Arduino_IDE_Setup.txt

Hardware

• Arduino-compatible microcontroller board with at least one hardware serial port
• SD card reader
• RS-232 to TTL/CMOS level shifter
• Serial cable
• Battery or usb power source for the microcontroller board

These boards have a small form-factor, and sd-card reader built-in:
Adafruit Feather 32u4 Adalogger
Adafruit Feather M0 Adalogger (20200916 broken)
Teensy 3.5
Teensy 3.6
Teensy 4.1 (not yet tested)

This adapter takes the place of a serial cable, and includes the level-shifter:
MounT

This adapter can power the microcontroller board from the M100:
BCR-USB-Power adapter

The following below are NOT needed if using the MounT adapter.
You would only need these for bread-boarding or building in a box attached by a cable.

RS-232<-->TTL/CMOS level-shifter module:
NulSom
Has a male connector and DTE pinout like a PC
Use the same special null-modem cable as for connecting a "Model T" to a PC.
Solder jumper wires on the back of the 9-pin connector to join pins 1, 4, and 6
DSR-DTR-DCD Wiring, top
DSR-DTR-DCD Wiring, bottom
This short-circuits the DSR/DTR detection, which pacifies TS-DOS so it will run, but means you can't test the bootstrap function except by wiring up a fake DTR/DSR signal using a pulldown resistor to gnd and a momentary button to vcc/3v3 on gpio pin 6.

RS-232 cable:
PCCables 0103
Or Any of these

TODO: find a ttl-serial module that actually supports the dsr/dtr lines.
https://www.pololu.com/product/126 breadboard-friendly single row of pins
https://www.amazon.com/dp/B0190WSINY/ needs jumper wires to a breadboard
Female plug, DCE pinout, needs a different serial cable, or adapters.

Usage:

Bootstrap Procedure

Assuming you are using a MounT adapter to host a Feather or Teensy.
Assuming you are using the BCR-USB adapter to power the MounT.
Assuming the portable is a Model 100.
Assuming you want to install TS-DOS.

1. Start with the Model 100 turned off.
   Plug the MounT and BCR adapters into the Model 100 and connect the micro-usb cable from the BCR adapter to the MounT.
   Eject the SD card.

2. Place an ascii format BASIC loader on the root of the SD card, renamed as LOADER.DO.
   You can use any of the loader files from dlplus.
   Example, take TS-DOS.100, and save it as LOADER.DO on the root of the SD card.
   Note the two associated files TS-DOS.100.pre-install.txt and TS-DOS.100.post-install.txt .

3. Turn on the Model 100 while the SD card is still ejected.
   The Teensy or Feather should now have a steady slow blinking LED, indication it's waiting for an SD card.
   Don't insert the SD card yet.

4. In BASIC, type RUN "COM:98N1E" and press Enter.

5. Insert the SD card.

6. Wait until the LED light goes out, then wait while the loader runs and eventually follow the on-screen directions.

You now have the ram version of TS-DOS installed! You can immediately use it to browse the contents of the SD card.
Exit BASIC and run TS-DOS.BA from the main menu. You can delete the TMP.DO file.

Notes

Ultimate ROM II TS-DOS loader

If you plan on using Ultimate Rom II, it has a "TS-DOS" feature which works by loading TS-DOS into ram on the fly, from a file on disk.
The file must be named DOS100.CO, and be in the root directory of the media.
This file can be downloaded from http://www.club100.org/nads/dos100.co, or,
a modified/updated version can be found here: http://www.club100.org/memfiles/index.php?direction=0&order=&directory=Ken%20Pettit/NewDos

"Model T" serial port control lines

At power-on the Model 100 rs232 port sets all data & control pins to -5v.
On RUN "COM:98N1E", pins 4 and 20 go to +5v.

To-Dos, or merely ideas, not necessarily realistic

• Change "PARENT.<>" to "..<>" if possible
• https://www.arduinolibraries.info/libraries/double-reset-detector_generic
• https://github.com/rocketscream/Low-Power
  simplify the sleep calls, same lib for both avr and samd21
• RTC (Teensy has built-in rtc)
• play & record audio as virtual cassette (Teensy has built-in audio, and enough cpu & ram to use it)
• Battery level (Adalogger has built-in voltage reference and adc, and a built-in lipo charger)
• A command-line that can be accessed from the computer's terminal emulator for quicker file manipulation
• Hayes modem emulation using an ESP8266 (https://www.cbmstuff.com/proddetail.php?prod=WiModem232)
• FTP server/client access using an ESP8266

BUGS/STATUS

• 20200916 Feather M0 isn't working.
  Unknown why. It used to work.

• Works with TS-DOS.

• Doesn't work with TEENY. (hangs)

• File transfers don't work with TpddTool.py .
  Seems to be due to mis-matches in handling the space-padding in the filenames?

• Some kind of working directory initial/default state issue, which affects Ultimate Rom II loading DOS100.CO on the fly. If you have DOS100.CO in ram, then UR-2 works all the time, because it will use that copy if available.
  TS-DOS from rom or ram, not via UR-2, seems to be working pretty well all the time.
  TS-DOS from rom or ram, not via UR-2, can successfully load a file like DOS100.CO from the root dir, but Ultimate Rom 2 usually can not load that same file, but sometimes it can.
  If you try to use TS-DOS from UR2 after a fresh power-cycle of both Arduino and M100, It doesn't work.
  But If you load TS-DOS some other way (for example, use a REX to switch to TS-DOS rom), and use TS-DOS to read the directory listing once, then switch roms back to UR-2, THEN the TS-DOS menu entry in UR-2 works (successfully loads DOS100.CO from the disk).
  Maybe TS-DOS does some kind of initialization that UR-2 isn't doing?
  UR-2 works fine with a real TPDD/TPDD2 and other emulators like dlplus and LaddieAlpha, so maybe there is some sort of default condition that we should be resetting to?

• If you use UR-2 to load TS-DOS in ram, and switch to a subdirectory like /Games while in TS-DOS, then exit TS-DOS, then you can't use TS-DOS any more, because the next time UR-2 tries to load DOS100.CO from disk, SD2TPDD looks for /Games/DOS100.CO, which does not exist.

• When UR-2 loads DOS100.CO, sucessfully or not, the LED doesn't shut off after.

• Sometimes displays the "PARENT.<>" directory entry even when you are already in the root dir.
  Goes away if you try to open PARENT.<> again when you're already in root.

Change-log

20200819 b.kenyon.w@gmail.com

• Moved PCB to its own repo
• Added TPDD2-style bootstrap function

20200817 b.kenyon.w@gmail.com

• Added PCB adapter "PDDuino_Feather".
  Takes the place of the serial cable and ttl-rs232 module.
  Supports Adafruit Feather 32u4 Adalogger and Adafruit Feather M0 Adalogger.

20191025 b.kenyon.w@gmail.com

• Support Adafruit Feather M0 Adalogger
  needs "compiler.cpp.extra_flags=-fpermissive" in ~/.arduino15/packages/adafruit/hardware/samd/1.5.4/platform.local.txt
• Combine all boards supported into the same code
  Time to break this out into a config.h file?

20180921 b.kenyon.w@gmail.com

• Support Teensy 3.5/3.6
• Support Adafruit Feather 32u4 Adalogger
• Macro-ify all serial port access, debug and tpdd client
• sleepNow() powersaving, idles at 3ma
• dmeLabel[] & setLabel() TS-DOS shows current working dir in top-right corner
• disk-activity led

---

v0.2 (7/27/2018)

• Added DME support
• Corrected some file name padding bugs

v0.1 (7/21/2018)

• Initial testing release with basic TPDD1 emulation