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NewtonROMReader

This archive contains the PCB layout and firmware source code for my Apple Newton MessagePad ROM board reader/programmer.

The Newton ROM Reader reads the contents of Apple MessagePad MP2x00 ROM boards. Besides the well known US and German ROM, this programmer can read prototype ROM boards for further research.

Using the alternative Flash ROM Board, the ROM Reader can also program the Flash chips and create new ROM Boards with patched or alternative operating systems.

CAUTION

  • Use an original Arduino Due. Do NOT use a Mega 2560!
  • Never insert or remove the ROM card while the programmer is powered!
  • All operations are final! There is no undo! There is no confirmation.

Reader/Programmer

Assembling the Programmer requires some advanced soldering skills. The pin headers must be soldered around the outside of the board facing down. They must be flush with the PCB on the top, or the ROM board will not fit.

The SD Card connector is soldered to the underside of the board. The top of the connector should be insulated using an ample amount of tape, avoiding a short circuit with header pins on the Arduino. ALternatively, the colliding pins on the Arduino board can be cut off.

The DIMM memory socket is more difficult to solder. The pin pitch is relatively small. To make sure that the soldering is correct, the first tool to run in the Programmer should be the short circuit test.

The last solder part is easy, but must not be forgotten. It's a jumper that sets the power to 3.2V. Connect the two eyes marked with an asterisk (*).

:
:   Lower left corner of the PCB
|
| ooo ooo
| ooo **o
|     ...... ........
+--------------------- - -

The Programmer board should be mounted on an Arduino Due. It MUST NOT be used with an Arduino Mega 1280/2560. The Mega runs at 5V and will likely destroy any ROM, Flash, or SD card inserted into the Programmer. The Due runs at the required 3.2V. If the large USB-A port of the Arduino blocks access to the SD Card slot, you have the wrong board!

The Programmer communicates with the user via USB connection to the Programming port. No extra power connection is required. There is no extra software for the Programmer. Users must use a serial terminal program to connect via the Programming USB port (57600 bps/baud 8N1).

Firmware Source Code

The source code comes as an Arduino sketch .ino file and a number of additional source and header files. The "SdFat" library by Bill Greimann must be installed within the Arduino system Tools > Manage Libraries....

Load the .ino file and set the board to Arduino Due (Programming Port), then choose the right port from the Tools > Port menu.

Open the serial monitor Tools > Serial Monitor and press Ctrl-U to upload the firmware to the Programmer.

PCB Layout

The Programmer PCB was designed with Eagle CAD 7.7.0 Stadard Edition. It's a two layer board with no exeptional requirements.

The SO-DIMM 72 modules are not very common anymore and are somewhat hard to find. The SD Card socket is a standard SMD part. Pin headers should be square shaped to fit the Arduino receptacle well.

Usage

The Programmer writes a 90's style menu over the USB serial port connection. Functions can be selected by typing the command key and Return.

  • h: Check all connectors on the board for short circuits. This tool helps verifying that there are no bridges in the SO DIMM connector soldering. Never run this command with a ROM board or SD Card inserted!
  • 0: Select the ROM area from 0x00000000 to 0x00800000 which corresponds to the regular ROM and Apple system ROM extension (REx).
  • 1: This page can be programmed with an extension block of up to 8MB.
  • 2, 3: Experimental blocks. These should be mapped to 0x10000000 and can contain 8MB extensions each. This however is not yet verified.
  • p: Print the contents of the Flash as a hex dump with ASCII. Pressing return will print the next block. Pressing any other key followed by enter will bring you back to the main menu.
  • c: Check if the Flash memory is empty (all addresses return 0xFFFFFFFF).
  • e: Erase all sectors in the selected Flash area.
  • w: Write the content of a file on SD card or on an USB Drive to the current Flash page. Filenames for pages 0 to 3 are set to "rom.bin", "rex1.bin", "rex2.bin", and "rex3.bin".
  • 'v': Verify the Flash content with the corresponding file on SD Card or USB Drive.

ToDo's

  • the SO DIMM footprint is really hard to solder, the pads are too big and solder tends to short the pins
  • the LED can not be controlled because it is connected to a ROM Board output
  • address and data pins should be connected to 32 bit registers, making the pin-by-pin addressing obsolete and the programmer much faster
  • the SPI port should be connected to a hardware SPI
  • there should be an option for a display and four buttons
  • the SD Card connecter must have pull-ups on most pins, and the Card Detect and Write Protect pins should be connected to some pin