Quote:
Originally Posted by Andy Brockway
How would we wire the Stellaris without the Booster Pack?
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First, take a look at the
GPIO Breakout BoosterPack User's Manual. There is a schematic and several tables that will help identify the LaunchPad signals used by the Gamepad Firmware so that you can connect them without the BoosterPack.
Looking at
Table 2-3. Standard BoosterPack Pinout Compatibility you'll see the columns divided into Pin, Breakout Use, and Standard. The Pin and Breakout Use columns will help you translate which gamepad button or analog input is mapped to which LaunchPad header pin. The LaunchPad has these headers labeled as J1, J3, J4, and J2 (from left to right) on the board. Pin one (e.g. J1.1) starts with the top most pin (with the square pad).
Table 2-2. Tiva Port and Pin Mapping may also be useful. You can match the Breakout signals with the ports labeled on the LaunchPad board.
Digital inputs will be wired similarly as described on the
wiki page, but you will connect the switch and ground wires directly to the port and ground pins on the LaunchPad.
Analog inputs will be a little trickier because the ADC on the Stellaris (or Tiva) microcontroller has a maximum source resistance requirement of 500Ω. The BoosterPack provides you with an amplifier that allows you to connect a very wide range of potentiometers rather than the less-than 500Ω range without it. Otherwise, wiring potentiometers is just as similar without the BoosterPack.
If you're just using buttons or other digital signals, then it is almost a toss-up. The BoosterPack makes it a little simpler, provides ESD protection, and has mounting holes that the LaunchPad does not have.
If you're also using analog, I would recommend using the BoosterPack, though it isn't impossible to do without it.
Hope this clears it up a bit.
-David