Friday, October 23, 2015

Downgrading Windows 8.1 Enterprise to Windows 8.1 Professional with a Professional N ISO

If you want to downgrade Windows 8.1 Enterprise to take advantage of the free Windows 10 upgrade then the following sources explain how to do this:

This will work if you have the Professional installation media, however if you want to do this with a Professional N ISO then there are two minor changes:

  • Change ProductName to Windows 8.1 ProfessionalN
  • Change EditionID to ProfessionalN
And then you'll be good to go. Without the 'N' addition you will not get the option to Keep Windows settings, personal files, and apps. It took a few iterations to figure this out so I hope this saves someone some time.


Tuesday, May 5, 2015

Recapping a Sega Game Gear

I got a couple of Sega Game Gears in a auction a while back, sold as not working. This is a fairly common experience as the GG's have terrible caps which tend to leak and go bad. Luckily the fix is a fairly straight forward recapping and then you should be good to go.

I started on this last night, here are a couple of pic for reference for anyone else that wants to take a shot at this. I'll update with more posts as I go.

First off, decapping and cleaning the audio board.

So this is what it looks like:
You can see all the gunk from the leaking caps around the coil.

More horrible leaked electrolyte on the bottom of the board
My process is to snip the caps in half with a very sharp set of clippers making sure that I don't apply pressure to the solder joints.

The target cap is the little guy in the bottom left

Snipped in half

Start by snipping the cap in half. These things stink like bad fish :( nasty...
Once you have half of the cap off you should be able to gently remove the bottom half leaving the two legs exposed.

Most of the cap removed
After that you can gently pry off the base plastic of the cap and then fairly easily de-solder the legs. Use some flux and add solder initially to get the legs off and to get through any build up of electrolyte residue.

Board after de-soldering all the caps

Finish off with a good circuit board cleaning spray or as close to 100% isopropol alcohol as you can get and it comes up fairly nicely:

De-soldered and cleaned


Monday, March 16, 2015

Building the Tapuino R2


The Tapuino has gone through several iterations, this post is a revisit of the build instructions containing these updates.

DISCLAIMER: If you build this and it blows up your C64, sets your house on fire, kidnaps your dog or any other negative occurrence, I take no responsibility for this or accept no liability whatsoever. That said, I will do my best to help troubleshoot any builds (I do take responsibility for all positive occurrences ;)).

I would highly suggest that you read this entire post at least once before building the Tapuino!

Note: code and hardware design files can be found on my GitHub at:

So lets get started. Firstly a bill of materials:

Major components:
  • Arduino Nano V3
  • 16x2 LCD Display with I2C backpack
  • SD Card module with built-in level conversion
  • 40 wire Dupont female-female 'ribbon'
I got all of this from eBay. Here is an example shopping list:

Additional components:
  • Piece of vero board. The one I got was 100mm wide x 200mm long. This is also known as strip board and must be the kind with strips of copper (as opposed to individual 'cells')
  • 32 pin (16x2) WIDE dip socket (this is what the Nano will plug into) or 2x15 female headers
  • 6 pin (3x2) dip socket (for the opto-coupler)
  • A strip of male pin headers
  • A strip of male right-angle pin headers
  • 2 strips of female pin headers (sockets)
  • 1x 430 Ohm resistor
  • 4x Tactile switches (6x6)
  • 1x 4N25 Opto-coupler
  • Some jumper wire (I use single core wire from a piece of telephone cable)
Here are examples of the headers:

Here is a schematic of the board in Fritzing format:
Tapuino V2 schematic

So lets build the main board first. You'll want to put it together like this:
Top view of the main board

Note the minimum dimensions of the board: 29x17. You may wish to make the board larger to allow for mounting holes.

Before you assemble:

The Nano has 2x15 pins and the socket is 2x16 so if you use the socket make sure the extra pins are on the right (in the diagram above after the D12 and D13 pins), or use 2x15 pin female headers.

R1 = 430 Ohm
Green blocks = straight header pins.
Grey blocks = female headers

Break the header pins into appropriate size groups:
2x3 pins
1x6 pins
1x4 pins
and cut the female pin headers to size (mine were 40 pin, so cut down to 8 pins):

Bottom view of the main board

The lighter yellow bits are where the vero board has been cut. It is essential that you check that these tracks are cut properly. Use a multimeter to test for continuity between the tracks once cut. To cut the tracks on my prototype I used a small sharp drill bit that was luckily a perfect fit.
Please take note of the cut track between the two pins of R1 (under the resistor).

I would suggest that you solder in this order:
  1. 32 pin wide socket (or 2x15 pin female headers)
  2. 6 pin dip
  3. 2x3 pin header group next to the 6 pin dip
  4. Remaining pin headers
  5. Jumper wires

Feel free to extend the pin headers to access additional pins on the Nano if you like, I just wanted to keep it simple for wire-up later and expose only the pins necessary.

Next up is the button board, this is the much simpler V2 button board that uses internal pullups on the Nano and so doesn't need any resistors:
Top view of the button board

Note the minimum dimensions of the board: 20 x 13. You may wish to make the board larger to allow for mounting holes.

Green pin headers are right angle.The pinouts of the green pin headers, left to right are as follows: GND, BTN1, BTN2, BTN3, BTN4

Bottom view of the button board

Take careful note of the track to cut: on the 4th track (from the left) to isolate button 3 from button 1
Also note that the jumper wires for the ground lines are soldered through to multiple points. I achieved this by cutting the wires into individual sections:
  • ground line (top most line) there are 4 jumper wires of 4, 6, 6, 6 tracks in length.

Now lets install the components and connect it all up.
Firstly install the 4N25 opto-coupler into the 6 pin socket, noting where pin 1 is according to the vero board schematic. Here is a picture with the correct orientation:

Installing the 4N25 opto-coupler

Note the small dot on the chip, this indicates pin 1. The chip should be oriented such that pin 1 connects through to the 440 Ohm resistor (R1).

Next the Nano:

Installing the Nano

As discussed above, the Nano has 2x15 pins and the socket 2x16 pins. If you chose to use the 32 pin socket, care must be taken to place the Nano correctly. The Nano must be aligned so that the empty socket pins are on the right most pins of the socket as per the image above i.e. the Nano is mounted as close as possible to the opto-coupler.

If you trace out the circuit you will observe that the 2x3 pin headers between the opto and the Nano expose a ground and power rail (left is GND, right is PWR). You will use these rails to provide power to the LCD, SD Card and Button breakout boards.

Connect according to the legend in the main board image, here is a guide:

  • Power and Ground go to the rails described above
  • Nano A5 goes to SCL
  • Nano A4 goes to SDA
SD Card:
  • Power and Ground go to the rails described above
  • Nano D13 goes to SCK
  • Nano D12 goes to MISO
  • Nano D11 goes to MOSI
  • Nano D10 goes to SS
Button Board:
  • Ground go to the rail described above
  • Nano A3 goes to BTN1
  • Nano A2 goes to BTN2
  • Nano A1 goes to BTN3
  • Nano A0 goes to BTN4
Finally the pinout for the C2N connector to the board:
CN2 to Tapuino connector pinout

You will need to break out 8 pins from a pin header.
Solder the C2N connector to the pins in the following manner:

  • GND to PIN 1
  • PWR to PIN 2
  • READ to PIN 3
  • MOTOR to PIN 4
  • SENSE to PIN 5
  • WRITE to PIN 8
I recommend you heat-shrink the pins as above.

Your connector should look like the one above, the colour to pin map in my case is:
  • Black (GND) to PIN 1
  • Green (PWR) to PIN 2
  • White (READ) to PIN 3
  • Red (MOTOR) to PIN 4
  • Blue (SENSE) to PIN 5
  • Brown (WRITE) to PIN8
Should look something like this:
C2N connected to the Tapuino

PIN 1 (GND) is connected to the left-most pin of the female pin header.

Now all that is left to do is flash the sketch to the Nano, disconnect it from USB, insert an SD Card with TAP files, connect the Tapuino to the C64 and enjoy!

The U.I. is controlled as follows:

BTN 2 is ABORT (during a load) or BACK one directory if browsing

If you have directories on your SD card they will be indicated by an arrow in the right-most column of the LCD where the filename is displayed. Long filenames are now supported!

Caution: Do not connect the Nano to both the C64 and PC. Also check all soldering very carefully for shorts before wiring up to your beloved machine!

The astute reader will note that the bus connector has 2 additional pins that are not connected: CTRL1 and CTRL2. These are used in the MUX board to allow switching between the C64 and a real Datasette as a target device and will be covered in a future blog.

Hope you enjoyed this, it was a helluva post to write!


Saturday, January 10, 2015

Arduino Pro Micro Arcade Controller

A bloke at my local Makerspace decided to build himself a table top arcade machine, which came out pretty damn well!

I had had a similar plan a while back, but never got around to it and so had the buttons and controls on hand which I sold to him. With the build complete and the controls installed, he needed a way to hook the controls up to the MAME PC in the cabinet. I'd been playing around with some Arduino Pro Micro boards for a similar purpose (hooking up retro C64 joysticks to my PC) so these seemed like a really good option. At the current price on eBay of $6.60 from my favourite supplier, this was a really cheap option.

As there were 2 joysticks with 8 buttons each, a single Pro Micro wasn't going to be sufficient, so we used 2. The basic vero board layout was:

2 Joystick Vero board layout

Pretty simple, with just some track cutting to separate the two Pro Micro. Once the tracks were cut we soldered in so 24 pin wide DIP sockets, the end result looked like this:

The wiring to the controls for each Pro Micro was:

6Button 1Button 1
7Button 2Button 2
8Button 3Button 3
9Button 4Button 4
10Button 5Button 5
16Button 6Button 6
14Button 7 (Player 1)Button 7 (Player 2)
15Button 8 (Left Paddle or Insert Coin)Button 8 (Right Paddle or Insert Coin)

Once wired up all we needed was some firmware. The Arduino IDE comes with some basic USB HID support for keyboards and mice, but doesn't feature any joystick HID descriptor. To fix this you'll need to change two files in the core Arduino software: HID.cpp and USBAPI.h. These can be found in the hardware\arduino\cores\arduino for the 1.0.6 build and somewhere similar for the newer IDE builds.

NOTE: These files are based on code from this blog:

Add the following class definition to USBAPI.h

// Joystick
//  Implemented in HID.cpp
//  The list of parameters here needs to match the implementation in HID.cpp

typedef struct JoyState
  uint8_t  xAxis;
  uint8_t  yAxis;
  uint8_t  buttons;  // 8 general buttons
} JoyState_t;

class Joystick_

  void setState(JoyState_t *joySt);

extern Joystick_ Joystick;

Then in HID.CPP you'll need to add the Joystick descriptor, look for:


and add:


Then find:

const u8 _hidReportDescriptor[] = {

and add in:


// 8 buttons, X and Y

 0x05, 0x01,   // USAGE_PAGE (Generic Desktop)
 0x09, 0x04,   // USAGE (Joystick)
 0xa1, 0x01,   // COLLECTION (Application)
  0x85, 0x03,   // REPORT_ID (3)  (This is important when HID_SendReport() is called)

  0x05, 0x09,   // USAGE_PAGE (Button)
  0x19, 0x01,   // USAGE_MINIMUM (Button 1)
  0x29, 0x08,   // USAGE_MAXIMUM (Button 8)
  0x15, 0x00,   // LOGICAL_MINIMUM (0)
  0x25, 0x01,   // LOGICAL_MAXIMUM (1)
  0x75, 0x01,   // REPORT_SIZE (1)
  0x95, 0x08,   // REPORT_COUNT (8)
  0x81, 0x02,   // INPUT (Data,Var,Abs)

    0x05, 0x01, // USAGE_PAGE (Generic Desktop)
    0xa1, 0x00, // COLLECTION (Physical)
      // 2 8bit Axis
      0x09, 0x30, // USAGE (X)
      0x09, 0x31, // USAGE (Y)
      0x15, 0x80, // LOGICAL_MINIMUM (-128)
      0x25, 0x7F, // LOGICAL_MAXIMUM (127)
      0x75, 0x08, // REPORT_SIZE (8)
      0x95, 0x02, // REPORT_COUNT (2)
      0x81, 0x02, // INPUT (Data,Var,Abs)
    0xc0, // END_COLLECTION
 0xc0     // END_COLLECTION


Finally you need to add the implementation for the joystick:

// Joystick
//  The report data format must match the one defined in the descriptor exactly
//  or it either won't work, or the pc will make a mess of unpacking the data


#define joyBytes 3   // should be equivalent to sizeof(JoyState_t)

void Joystick_::setState(JoyState_t *joySt)
  uint8_t data[joyBytes];

  data[0] = joySt->buttons;  // Break 32 bit button-state out into 4 bytes, to send over USB
  data[1] = joySt->xAxis;  // X axis
  data[2] = joySt->yAxis;  // Y axis

  //HID_SendReport(Report number, array of values in same order as HID descriptor, length)
  HID_SendReport(3, data, joyBytes);
  // The joystick is specified as using report 3 in the descriptor. That's where the "3" comes from

Now that all the ground work is done, a simple .ino file will handle the joystick interface:

JoyState_t joySt;

#define MAX_AXIS 4
#define Y_MIN  0
#define Y_MAX 1

#define X_MIN  2
#define X_MAX 3

uint8_t joy_axis[MAX_AXIS] = {2,3,4,5};

#define MAX_BUTTONS 8
uint8_t joy_buttons[MAX_BUTTONS] = {6,7,8,9,10,16,14,15};

void setup()
  uint8_t i;
  pinMode(13, OUTPUT);

  for (i = 0; i < MAX_AXIS; i++) {
    pinMode(joy_axis[i], INPUT);
    digitalWrite(joy_axis[i], HIGH);

  for (i = 0; i < MAX_BUTTONS; i++) {
    pinMode(joy_buttons[i], INPUT);
    digitalWrite(joy_buttons[i], HIGH);

  joySt.xAxis = 0;
  joySt.yAxis = 0;
  joySt.buttons = 0;


void update_stick() {
  uint8_t i;

  joySt.xAxis = 0;
  joySt.yAxis = 0;
  if (digitalRead(joy_axis[Y_MIN]) == LOW) {
    joySt.yAxis = 128;
  } else if (digitalRead(joy_axis[Y_MAX]) == LOW) {
    joySt.yAxis = 127;

  if (digitalRead(joy_axis[X_MIN]) == LOW) {
    joySt.xAxis = 128;
  } else if (digitalRead(joy_axis[X_MAX]) == LOW) {
    joySt.xAxis = 127;

  joySt.buttons = 0;

  for (i = 0; i < MAX_BUTTONS; i++) {
    if (digitalRead(joy_buttons[i]) == LOW) {
      joySt.buttons |= 1 << i;


void loop() {

Thes files can be obtained from here: Joystick HID Files but I suggest that you patch the HID.cpp and USBAPI.h files manually to account for any variance between your and my Arduino IDE.

Have fun and keep on hacking!