Midify Installation: Game Boy SP

Here is a step-by-step example of how to install Midify into a Game Boy Advance SP.

SP with MIDI Jack

What you need

  • Game Boy Advance SP
  • Midify + Accessories
  • Tri-Wing Screwdriver
  • Small Phillips Screwdriver
  • Low-Wattage Soldering Iron with Fine Tip
  • Solder
  • Wire Cutters
  • Wire Strippers for 30AWG Wire
  • Utility Knife and/or Dremel Tool

Disassemble the SP

Use a small Phillips screwdriver to remove the battery cover.

Remove Battery Cover

Remove the battery

Remove Battery

Use a tri-wing screwdriver to remove the screws that hold the case together.

Remove Screws

Lift the back of the case off and set it aside.

Remove Rear Cover

Use a Phillips screwdriver to remove the three screws that hold the circuit board in place.

Remove PCB Screws

Tip the board up to reveal the ribbon connector for the LCD.

Lift PCB to reveal ribbon cable

Slide the brown part of the ribbon connector as shown to release the LCD ribbon cable.

Slide to unlatch ribbon cable

Remove the board from the case and set the case aside.

Remove PCB from case

Install Midify Board

Gather all the parts that came with your Midify kit.

Parts included in Midify kit

Use the double-sided tape to stick the Midify board to the SP board.

Put double-sided tape on back of Midify board

Stick Midify to SP board as shown

The labels on the Midify board are kind of hard to read. Here is a diagram showing what they are:

Midify Pinout


Connect the two Midify power supply (+ and -) pads to the SP board. + connects to pin 1 of the SP cartridge connector and – connects to pin 32. There isn’t much room inside the Game Boy so make sure you trim off any excess wire and re-strip the end. It’s best to run the wires around the chip on the Midify board instead of on top of it.

Midify Pad
Cartridge Connector Pin

Midify PS Connection Diagram

First, solder wires to the power supply pads

Next cut and strip the wires. Solder them to the connector pins.

A note about soldering with only two hands: The easiest way to make connections to the solder pads on the Midify and the SP boards is to first put a little blob of solder on the pad, then melt the blob as you set the end of the wire down into it.

Now it’s time to start making all the connections to the opposite side of the board. Start with the LED wire. Solder it to DL2 as shown.

Solder wire to DL2

Route the wire so that it doesn’t interfere with the LEDs or the buttons. As a general rule try to keep wires out of the white areas on the board.

Bend the wire around the edge of the board and to the other side.

Bend LED wire around board as shown

Flip the board back over. Route the wire below the battery connector and above the variable resistor (round gold-looking thing). Trim off any excess length, strip the end and solder the wire to the Midify LED pad.

Solder LED wire to Midify board

Some SP boards look slightly different than the one shown here. That’s okay; the connections are the same. You’ll just need to route the wires between the battery connector and the round coil that is below it if you have one of those boards.

Now start connecting Midify’s numbered outputs to the solder pads for the SP’s various buttons. The exact way you’d do this will vary depending on what you are using your Midified SP for. Just remember- if you change your mind about which note you want mapped to which button later it’s easy to reconfigure it without taking the SP back apart.

Here is a chart which shows which SP solder pad (TP) corresponds to which button so you can work out a custom map if you’d like:

Button Solder Pad List
TP0- A
TP1- B
TP2- Select
TP3- Start
TP4- Right
TP5- Left
TP6- Up
TP7- Down
TP8- R
TP9- L

SP Button Solder Points

For this tutorial we’ll assume that you are modding your SP for use with a synth cartridge that can play 8 notes. We’ll make the following connections (L and R aren’t used by the cartridge in our example but you can hook them up so that you can map them later if you’d like):

Midify Output
SP Connection
Button Name

Connect the wires and route them from the back of the board to the front just like you did with the LED wire.

Connect all button wires

Once again be careful to route the wires so that they don’t interfere with any buttons, LEDs, the variable resistor or any tall components. Keep them out of the white areas. Also note that the Midify board is very close to the large IC on the SP board. Make sure no wires or solder blobs protrude past the edge of the board where they could make contact with the IC pins.

Modify Case

Once you have connected all the button wires it’s time to modify the SP case. Start by clipping the + shaped standoff from the back half of the case with your wire cutters.

Remove plus-shaped standoff

Plus-shaped standoff removed

Use a knife or Dremel to completely remove the screw hole / standoff as shown.

Remove screw standoff

Screw standoff removed

Now remove the other half of the screw hole / standoff from the front half of the case.

Clip screw standoff

Screw standoff clipped

Use a knife or Dremel to shave the square-shaped standoff from the back half of the case (next to the battery connector hole) so that it is flush with the back of the battery compartment.

Trim the square flange around the variable resistor hole so that it is flush with the back of the battery compartment.

Remove two square standoffs

Now it’s time to drill some holes. Here is a PDF to help you drill them in the right spot:

Click to download drill guide

When you print it out make sure you disable any kind of scaling / reduction; it must print actual size.

Start with the hole in the battery compartment (this is needed so that one of the chips on the Midify board can protrude through a little and the case can close). Cut out the larger of the two templates from the PDF file and place it in the compartment.

Use an awl, center punch or something pointy to mark the center of the hole.

Mark center of hole with something pointy

Remove the template.

Use a small bit to drill a pilot hole where you marked. Keep drilling bigger and bigger holes until you reach 13/64″.

If you try to jump right to the 13/64″ hole you run the risk of cracking the case or not getting the hole right on your mark.

Drill consecutively larger holes until you get to 13/64

Battery compartment hole after drilling

Now repeat the process with the smaller template and the hole for the MIDI jack. Place the template as shown. Make sure the marked corner is lined up with the corner of the case.

Line marked corner of jack hole template with corner of case

Mark the center of the hole with your pointy tool of choice.

Mark jack hole with something pointy

Drill the hole, once again starting small and working your way up to 13/64″.
Drill jack hole

Jack hole after drilling

Once you are all done, the back half of the case should look like this:

Holes drilled and standoffs removed

Install MIDI Jack

Set the case aside and find the 2.5mm jack. Solder two wires to it as shown. Use two different colors so you can get the polarity right (in this picture the black goes to the sleeve and the yellow goes to the tip).

Connect wires to jack

MIDI Jack Pinout

Install the jack into the hole you drilled into the side of the SP case. It’s easiest to do this if you orient the connector so that the solder tabs are pointing up as shown.

Insert jack into hole with solder tabs up

Rotate the jack so that the tip contacts and all the solder tabs are down (you don’t want anything protruding above the edge of the case).

Rotate jack so solder tabs are down

Install the washer and nut to hold the jack in place. You can tighten it down with a 9/32″ socket or pliers (be careful not to scratch your SP case)

Tighten nut onto jack

Connect the two jack wires to the Midify board.

Midify Input
Jack Connection

Connect jack wires to Midify board

Reassemble SP

Temporarily set the SP board in the back half of the case.

Set board in back half of case

Reconnect the ribbon cable for the LCD by inserting the cable into the connector and sliding the brown tabs back into position. You should be able to tug on the cable a little bit without it coming out if it is locked in properly.

Reconnect ribbon cable

Now fold the SP board back into the front half of the case. Fold the back half out of the way and reinstall the screws that hold the SP board in place. One of the screws is now located under the Midify board so it may be easier just to leave that one out.

Replace 2 of the 3 PCB screws

Make sure the L & R buttons as well as the plastic caps for the power and volume controls are in place.

Reinstall the back cover. Make sure the wires that go to the MIDI jack don’t interfere with anything. You will feel some pressure from all the wires you just installed, but a little bit won’t hurt anything. If you have to press very hard, however, pull the cover back off and look for anything that might be pinching.

You may need to slide the Midify board around a little bit so that the chip lines up with the hole you drilled in the battery compartment.

Line up chip in hole

Replace all the back cover screws (except the one by the MIDI jack).

Replace all screws except one by jack

Reinstall the battery and battery cover.

Reinstall battery

Reinstall battery cover

Configure Midify

Use the included cable to connect your SP to a MIDI keyboard.

Connect to MIDI keyboard

Insert your synth cartridge and power on the SP.

The default key mapping for Midify is for each note in the octave starting at Middle C to correspond to one of the 12 outputs. Since this example assumes you are using a synth cartridge that only uses the first 8 outputs and that they need to be mapped to an octave’s worth of white keys only, we will use the keyboard to select the “Default 8-Note Map” option.

Configure Midify for Default 8-Note Map

Hold down the 5 config keys on the MIDI keyboard (note numbers 48-52; C, C#, D, D# and E below Middle C). The LED on the SP will start to flash slowly (it may flash on/off or red/green).

Press and release note number 54 (F# below Middle C). The LED will flash a few times quickly to let you know that it has performed the requested action.

Release the 5 configuration keys. The LED will stop flashing and you are ready to start playing some music!