Adafruit Retrogame GPIO expansion - MCP23017 #2
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Interrupts coming from MCP23017 are handled using GPIO inputs. Once an interrupt is received, the driver check both interrupts states: this avoids losing interrupts signals.
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This rules! I was about to try writing this exact thing. Thanks vdownemail! |
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I may be missing something, but it looks like your 6 buttons per player includes the START and COIN buttons. So, for example, you still couldn't play Defender, which needs 5 buttons, or the Street Fighter series, which needs 6 buttons per player (not including START or COIN). |
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Thank you monkeywidget ! MCP23017 can expand to 8 inputs per player (total 16 inputs) and this include 4 directions + 4 buttons. However there are other GPIOs on the raspberry you can use. I mapped only 2 GPIO in order to process MCP23017 interrupts; in addition 3 more GPIOs are used for SCL/SDA communication. The remaining GPIOs are all free. I haven't tested with 2 MCPs but I think that if you need an ultra-dense button configuration you can use a second chip changing (of course) the chip address of the second MCP. See ya |
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PS: you can find other info here http://www.raspberrypi.org/forums/viewtopic.php?f=78&t=74702 |
Adafruit Retrogame modified in order to expand GPIO inputs. The configuration supports 2 player game: every player can use 6 buttons. There are also 2 buttons that controls ESC and PAUSE.