Preparing the Cape

Before you build this section

You are going to need some form of:

  • Beaglebone Proto Cape
  • Male 0.1" header
  • Small gauge wire
  • 16-conductor ribbon cable

Assembling the Cape

Start by assembling the cape itself. Your cape should at least come with male headers, or possibly male-female headers that allow stacking. I prefer the stacking connectors, as they allow you to shove jumper wires in to test a connection here or there.

There are two connectors, each with two rows of 23 pins each. That means you must make 92 solder joints, while keeping all of the pins perfectly vertical. If you have the male-female stacking connectors, the best way is to insert both connectors into the proto cape, and lie it upside down and work from the bottom. If you have the non-stacking connectors, insert the connectors and solder from the top.

Once you are done, check continuity between the holes where the connectors are inserted, and the pads where the signals are available to you. I had a couple of spots that I missed and skipping this created some troubleshooting headaches for me.

If all the solder joints are good and the signals are arriving on the proto cape, carefully test fit the cape onto the BeagleBone Black. There is a fine line between "enough force to make 96 pins fit in" and "enough force to break one or both boards". Work carefully, and you should be able to verify that all the pins are in alignment. Separate the boards again.

Constructing the LED connector

 

Find a free spot on your proto cape, and install two rows of 0.1" header. Take your narrow-gauge wire, and make the following connections. I used 26 AWG, solid core wire, but I did not have a very easy time making these connections. Any technique that works for working on protoboard will work fine here, as there are no electronics involved, just some electrical connections.

 

  • Led Connector
  • Row 1, Left Pin
  • Row 1, Right Pin
  • Row 2, Left Pin
  • Row 2, Right Pin
  • Row 3, Left Pin
  • Row 3, Right Pin
  • Row 4, Left Pin
  • Row 4, Right Pin
  • Row 5, Left Pin
  • Row 5, Right Pin
  • Row 6, Left Pin
  • Row 6, Right Pin
  • Row 7, Left Pin
  • Row 7, Right Pin
  • Row 8, Left Pin
  • Row 8, Right Pin
  • BBB cape
  • P8-7
  • P8-9
  • P8-8
  • GND
  • P8-13
  • P8-14
  • P8-10
  • GND
  • P8-12
  • P8-11
  • P8-16
  • P8-15
  • P9-16
  • P9-12
  • P8-26
  • GND
  • Signal meaning
  • Red 1
  • Blue 1
  • Green 1
  • Ground
  • Red 2
  • Blue 2
  • Green 2
  • Ground
  • Select A
  • Select B
  • Select C
  • Select D
  • Clock
  • Latch
  • Output Enable
  • Ground
  • BBB signal
  • Gpio2[2]
  • Gpio2[5]
  • Gpio2[3]
  • Ground
  • Gpio0[23]
  • Gpio0[26]
  • Gpio2[4]
  • Ground
  • Gpio1[12]
  • Gpio1[13]
  • Gpio1[14]
  • Gpio1[15]
  • Gpio1[19]
  • Gpio1[28]
  • Gpio1[29]

This is an area where you must proceed slowly. Not all LED matrixes are the same. There is a good article on the number of combinations you may find. I wired my panels for the green/blue swap that article describes, as they seemed to need it.

Wiring the controls

Ideally, you should do similarly to the above, and wire up two male headers, one for each player, and then attach the player controls. After burning my fingertips too many times, and making other errors while assembling the LED connector, I got lazy and soldered wires directly to the cape. The wire ordering is a little odd, as I went from "a little lazy" to "I'm finishing this today at whatever the cost." Everything can be fixed in software.

 

Do not hook anything to the other end of these wires yet. The control panels come in a later step. You may wish to mark the wires with labels, or pieces of heat shrink tubing, so that you don't have to trace the wires again later. Also, attach two lengths of wire to the GND pads. This will form the 'other end' of the controls.

  • Player 1
  • Up
  • Down
  • Left
  • Right
  • Action - Primary
  • Action - Secondary
  • Start - 1 Player
  • Start - 2 Players
  • Beaglebone Black Pin
  • P8 - 38
  • P8 - 44
  • P8 - 41
  • P8 - 42
  • P8 - 39
  • P8 - 40
  • P8 - 45
  • P8 - 46
  • Beaglebone Black Signal
  • Gpio2[15]
  • Gpio2[9]
  • Gpio2[10]
  • Gpio2[11]
  • Gpio2[12]
  • Gpio2[13]
  • Gpio2[6]
  • Gpio2[7]
  • Software Gpio
  • 79
  • 73
  • 74
  • 75
  • 76
  • 77
  • 70
  • 71
  • Player 2
  • Up
  • Down
  • Left
  • Right
  • Action - Primary
  • Action - Secondary
  • BeagleBone Black Pin
  • P8 - 35
  • P8 - 31
  • P8 - 33
  • P8 - 34
  • P8 - 32
  • P8 - 36
  • BeagleBone Black Signal
  • Gpio0[8]
  • Gpio0[10]
  • Gpio0[9]
  • Gpio2[17]
  • Gpio0[11]
  • Gpio2[16]

 

  • Software Gpio
  • 8
  • 10
  • 9
  • 81
  • 11
  • 80
These pin assignments reuse pins that have other uses on the BeagleBone Black. The HDMI display must be disabled. Also, the controls will affect the state of the SYSBOOT pins, possibly causing bootup issues.

Wiring the Audio

Luckily, this part is easy. Simply attach a wire to the +5V pads, and a wire to the GND pads. Make sure that the other end is insulated so that you don't short anything out later.

This guide was first published on May 04, 2015. It was last updated on Sep 20, 2018. This page (Preparing the Cape) was last updated on May 04, 2015.