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The C64 Keyboard must be connected to MBHP DOUT (DOUT1: J3(Pin D0 to D7)) and MBHP DIN (DIN1: J3/J4(Pin D0 to D7))
See DOUTX4 ⇒ http://ucapps.de/mbhp/mbhp_doutx4.pdf
See DINX4 ⇒ http://ucapps.de/mbhp/mbhp_dinx4.pdf
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